Lead Poisoning

Environmental MONDO:0018019 Pathograph 17 heavy metal poisoning

Lead poisoning is a toxic condition caused by acute or chronic exposure to lead, a non-essential heavy metal encountered through deteriorating lead-based paint, contaminated drinking water, battery manufacture and recycling, mining and smelting, electronic waste, and other occupational or environmental sources. Children are especially vulnerable because lead disrupts nervous system development even at relatively low blood lead concentrations. Lead toxicity reflects calcium mimicry, inhibition of heme biosynthesis, oxidative stress, mitochondrial dysfunction, and chronic accumulation in bone and kidney. Clinical manifestations include abdominal pain, constipation, anemia, cognitive impairment, peripheral neuropathy, nephropathy, and hypertension.

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Mappings
2
Definitions
0
Inheritance
12
Pathophysiology
2
Histopathology
12
Phenotypes
17
Pathograph
0
Genes
4
Treatments
2
Subtypes
2
Differentials
2
Datasets
3
Trials
0
Models
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Mappings

MONDO
MONDO:0018019 lead poisoning
skos:exactMatch MONDO
Primary MONDO disease identifier for this lead poisoning entry.
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Definitions

2
Clinical multisystem toxicity case definition for lead poisoning
Lead poisoning is a toxic disorder caused by exposure to the non-essential heavy metal lead, with multisystem adverse effects and no safe exposure threshold identified.
CASE_DEFINITION Disease-level clinical framing across acute and chronic lead exposure
Show evidence (2 references)
PMID:40981357 SUPPORT Other
"Lead (Pb) is a non-essential, toxic heavy metal with no known biological function that has caused widespread environmental contamination throughout human history."
Supports the core disease framing as toxic illness caused by exposure to a non-essential heavy metal.
PMID:40981357 SUPPORT Other
"Pb toxicity represents one of the most persistent environmental health challenges, with no safe exposure threshold identified."
Supports inclusion of the no-safe-threshold concept in the disease-level definition.
Practical diagnostic definition for clinically significant lead exposure
Clinical definition of lead poisoning relies on demonstration of elevated venous blood lead concentration in the relevant clinical context, with body-burden assessment needed when chronic lead nephropathy is suspected.
DIAGNOSTIC_CRITERIA Clinical diagnosis and complication-focused workup in exposed patients
Show evidence (2 references)
PMID:37478813 SUPPORT Human Clinical
"Consequently, in 2021, the Centers for Disease Control and Prevention (CDC) reduced its blood lead reference value from 5 µg/dL to 3.5 µg/dL in pediatric patients, 1 to 5 years old."
Supports venous blood lead concentration as the central contemporary clinical benchmark for defining significant pediatric lead exposure.
PMID:8475950 SUPPORT Other
"Only evaluation of body lead stores by either the EDTA lead mobilization test or by x-ray fluorescence is helpful in diagnosing lead nephropathy."
Supports refinement of the clinical definition in chronic nephropathy, where blood lead alone may not capture retained body burden.
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Subtypes

2
Acute Lead Poisoning
Acute lead poisoning follows high-dose ingestion or inhalation and may present with severe abdominal pain, vomiting, encephalopathy, hemolysis, acute kidney injury, and rapidly rising blood lead concentrations.
Show evidence (1 reference)
PMID:3103564 SUPPORT Human Clinical
"A prospective study of an epidemic outbreak of acute lead poisoning characterized by unusual clinical and analytic manifestations was carried out."
Directly supports acute lead poisoning as a clinically recognizable subtype.
Chronic Lead Poisoning
Chronic lead poisoning results from sustained lower-level exposure with progressive neurocognitive effects, constipation, anemia, peripheral neuropathy, chronic kidney disease, and hypertension. Bone stores become a long-term endogenous reservoir for recurrent lead release.
Show evidence (1 reference)
PMID:1030853 SUPPORT Human Clinical
"Clinical, biochemical, haematological and erythrokinetic studies were performed on 63 adult males with prolonged lead exposure."
Supports chronic lead poisoning as a distinct syndrome of prolonged exposure with multisystem clinical findings.
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Pathophysiology

12
Lead absorption
Lead enters the body through gastrointestinal and respiratory absorption.
transmembrane transport link ⚠ ABNORMAL
Show evidence (1 reference)
PMID:40981357 SUPPORT Other
"Pb enters organisms through multiple pathways and causes severe health impacts across all biological systems, with particularly devastating neurodevelopmental and bone effects in children and cardiovascular and reproductive consequences in adults."
Supports lead entry through multiple exposure pathways and its capacity to reach multiple organ systems.
Systemic lead distribution
Absorbed lead circulates systemically and persists in biologic tissues, allowing redistribution into bone, erythroid tissues, neurons, and kidney.
Show evidence (1 reference)
PMID:40981357 SUPPORT Other
"The metal demonstrates remarkable persistence in biological systems, with approximately 90% of it stored in bone tissue for decades, mimicking calcium due to its similar ionic properties."
Supports systemic persistence and redistribution of lead into long-lived tissue reservoirs.
Bone sequestration of lead
Most retained lead is deposited in bone, where it replaces calcium within mineralized tissue and serves as a long-term endogenous source of ongoing exposure during bone turnover.
osteoblast link
calcium ion homeostasis link ⚠ ABNORMAL
Show evidence (2 references)
PMID:40981357 SUPPORT Other
"The metal demonstrates remarkable persistence in biological systems, with approximately 90% of it stored in bone tissue for decades, mimicking calcium due to its similar ionic properties."
Supports bone sequestration as a defining kinetic feature of lead poisoning.
PMID:20643234 SUPPORT Model Organism
"These data show that lead increases bone turnover resulting in weaker cortical bone in adult female mice and suggest that lead may exacerbate bone loss and osteoporosis in the elderly."
Mouse data support direct adverse skeletal consequences of chronic bone lead deposition.
Inhibition of delta-aminolevulinic acid dehydratase
Lead inhibits delta-aminolevulinic acid dehydratase (ALAD), a zinc-dependent heme biosynthetic enzyme. This is an early and sensitive biochemical lesion of lead exposure and contributes to defective heme production.
erythrocyte link
heme biosynthetic process link ↓ DECREASED
Show evidence (1 reference)
PMID:3442386 SUPPORT Human Clinical
"ALAD is a zinc metalloenzyme whose inhibition by lead is the first and most sensitive indicator of lead exposure and whose decreased activity has been implicated in the pathogenesis of lead poisoning."
Directly supports ALAD inhibition as a central biochemical mechanism in lead toxicity.
Erythrocyte pyrimidine 5'-nucleotidase deficiency
Lead intoxication causes an acquired erythrocyte pyrimidine 5'-nucleotidase deficiency, leading to abnormal pyrimidine nucleotide handling and basophilic stippling.
erythrocyte link
pyrimidine-containing compound biosynthetic process link ⚠ ABNORMAL
Show evidence (1 reference)
PMID:965496 SUPPORT Human Clinical
"Lead intoxication is accompanied by an acquired deficiency of erythrocyte pryimidine-specific, 5'-nucleotidase."
Supports lead-induced erythrocyte enzymatic injury as a mechanism of hematologic toxicity.
Hemolytic erythrocyte injury
Lead-associated erythrocyte injury increases hemolysis and contributes to clinically significant anemia.
erythrocyte link
Show evidence (1 reference)
PMID:965496 SUPPORT Human Clinical
"The findings indicate that the hemolytic anemia and increased basophilic stippling characteristic of certain cases of lead intoxication may share a common etiology with essentially identical features of the genetically determined disorder."
Supports hemolytic erythrocyte injury as a distinct hematologic event in lead intoxication.
Calcium mimicry in neuronal signaling
Lead acts as a calcium substitute in intracellular signaling, perturbing calcium-dependent neuronal regulatory pathways.
neuron link
calcium ion homeostasis link ⚠ ABNORMAL
Show evidence (1 reference)
PMID:8247416 SUPPORT Other
"Our investigations of the ability of lead to substitute for calcium in several intracellular regulatory events are reviewed in the context of the neurotoxicity produced by this heavy metal."
Supports calcium mimicry as a distinct upstream mechanism of lead neurotoxicity.
Protein kinase C dysregulation
Lead-induced disturbance of second-messenger signaling alters protein kinase C activation and other calcium-regulated neuronal signaling outputs.
neuron link
Show evidence (1 reference)
PMID:8247416 SUPPORT Other
"Taken together these studies implicate second messenger metabolism and protein kinase activation as potential sites for the disruptive action of lead upon nervous system function."
Supports protein kinase activation dysregulation as a distinct downstream neuronal signaling event in lead toxicity.
Mitochondrial dysfunction
Lead poisoning perturbs mitochondrial function across multiple organ systems, contributing to cellular energy failure and tissue injury.
mitochondrion organization link ⚠ ABNORMAL
Show evidence (1 reference)
PMID:40981357 SUPPORT Other
"On a molecular level, Pb disrupts cellular processes through ion mimicry, replacing essential metals in enzymes and proteins and leading to mitochondrial dysfunction, oxidative stress, DNA damage, and epigenetic modifications."
Supports mitochondrial dysfunction as a distinct downstream mechanism of lead toxicity.
Oxidative stress response
Lead exposure increases oxidative stress signaling and contributes to multisystem cellular injury.
response to oxidative stress link ↑ INCREASED
Show evidence (1 reference)
PMID:40981357 SUPPORT Other
"On a molecular level, Pb disrupts cellular processes through ion mimicry, replacing essential metals in enzymes and proteins and leading to mitochondrial dysfunction, oxidative stress, DNA damage, and epigenetic modifications."
Supports oxidative stress as a distinct downstream mechanism of lead toxicity.
Proximal tubular lead accumulation
Lead accumulates in proximal renal tubular cells, where it forms inclusion bodies and produces potentially reversible proximal tubular dysfunction in acute toxicity.
proximal tubule cell link
renal absorption link ⚠ ABNORMAL
Show evidence (2 references)
PMID:2650022 SUPPORT Other
"Exposure to lead results in accumulation in proximal renal tubular lining cells in the form of morphologically discernible inclusion bodies which are lead-protein complexes."
Supports proximal tubular accumulation as the initial renal lesion of lead nephrotoxicity.
PMID:2650022 SUPPORT Other
"Acute nephrotoxicity consists of proximal tubular dysfunction and can be reversed by treatment with chelating agents."
Supports proximal tubular dysfunction as the dominant acute renal consequence of lead accumulation.
Chronic tubulointerstitial nephropathy
Chronic lead nephrotoxicity is a tubulointerstitial renal disease marked by interstitial fibrosis, progressive nephron loss, and associated hyperuricemia, gout, and hypertension.
proximal tubule cell link
Show evidence (2 references)
PMID:2650022 SUPPORT Other
"Chronic lead nephrotoxicity consists of interstitial fibrosis and progressive nephron loss, azotaemia and renal failure. Potential complications of lead nephropathy include gout and hypertension."
Supports the chronic fibrosing renal phenotype and its hypertensive complication.
PMID:8475950 SUPPORT Other
"Renal function and biopsy studies showed that lead nephropathy is a chronic tubulointerstitial renal disease with modest proteinuria which frequently presents with hyperuricemia, gout and hypertension."
Confirms the clinical pattern of chronic tubulointerstitial nephropathy in lead poisoning.
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Histopathology

2
Basophilic stippling of erythrocytes
Peripheral blood smear may show basophilic stippling of red blood cells due to aggregated ribosomes in lead intoxication. This is a classic but nonspecific microscopic finding.
Show evidence (2 references)
PMID:6202140 SUPPORT Human Clinical
"Basophilic stippling of red blood cells (BSC) has been noted in lead intoxication since 1899 and has been considered a classic laboratory sign of lead poisoning since that time."
Supports basophilic stippling as the classic hematologic microscopic finding in lead poisoning.
PMID:1030853 SUPPORT Human Clinical
"Other associated findings were: higher reticulocyte counts and more basophilic stippling of the RBCs, more sideroblasts and greater erythroid hyperplasia of the bone marrow"
Supports basophilic stippling as an observed microscopic feature in chronically lead-exposed patients.
Proximal tubular nuclear inclusion bodies
Early lead nephropathy is characterized by proximal tubular nuclear inclusion bodies formed by lead-protein complexes, alongside chronic tubulointerstitial disease and fibrosis.
Show evidence (2 references)
PMID:2650022 SUPPORT Other
"Exposure to lead results in accumulation in proximal renal tubular lining cells in the form of morphologically discernible inclusion bodies which are lead-protein complexes."
Supports proximal tubular nuclear inclusion bodies as a characteristic microscopic renal lesion in lead nephrotoxicity.
PMID:19106433 SUPPORT Other
"both entities are characterized by tubulointerstitial disease and fibrosis, but only early lead nephropathy is characterized by the presence of proximal tubule nuclear inclusion bodies, due to the combination of lead with a lead binding-protein."
Distinguishes lead nephropathy histopathology from cadmium nephropathy by the presence of proximal tubular nuclear inclusion bodies.
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Pathograph

Use the checkboxes to hide or show graph categories. Hover nodes for evidence and cross-linked metadata.
Pathograph: causal mechanism network for Lead Poisoning Interactive directed graph showing how pathophysiology mechanisms, phenotypes, genetic factors and variants, experimental models, environmental triggers, and treatments relate through causal and linked edges.
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Phenotypes

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Blood 1
Anemia FREQUENT Anemia (HP:0001903)
Show evidence (2 references)
PMID:37478813 SUPPORT Human Clinical
"Exposure to lead may cause severe adverse effects such as anemia, neurologic damage, developmental disorders, and reproductive disorders."
Supports anemia as a major adverse clinical effect of lead exposure.
PMID:965496 SUPPORT Human Clinical
"The findings indicate that the hemolytic anemia and increased basophilic stippling characteristic of certain cases of lead intoxication may share a common etiology with essentially identical features of the genetically determined disorder."
Supports hemolytic anemia as a clinically important hematologic manifestation of lead intoxication.
Cardiovascular 1
Hypertension OCCASIONAL Hypertension (HP:0000822)
Show evidence (1 reference)
PMID:8475950 SUPPORT Other
"Renal function and biopsy studies showed that lead nephropathy is a chronic tubulointerstitial renal disease with modest proteinuria which frequently presents with hyperuricemia, gout and hypertension."
Supports hypertension as a common complication of chronic lead nephropathy.
Digestive 1
Constipation FREQUENT Constipation (HP:0002019)
Show evidence (1 reference)
PMID:29531415 SUPPORT Human Clinical
"In February 2016, we noticed a steep increase in the numbers of oral opium users referred to our poison treatment centre with abdominal pain, anaemia and constipation."
Outbreak data provide direct human clinical support for constipation as a common presenting feature of lead poisoning.
Genitourinary 1
Chronic kidney disease OCCASIONAL Chronic kidney disease (HP:0012622)
Show evidence (1 reference)
PMID:9300927 SUPPORT Other
"Chronic occupational exposure to lead, or consumption of illicit alcohol adulterated with lead, has also been linked to a high incidence of renal dysfunction, which is characterized by glomerular and tubulointerstitial changes resulting in chronic renal failure, hypertension, hyperuricemia, and gout."
Supports chronic kidney disease as a clinically important manifestation of chronic lead nephrotoxicity.
Head and Neck 1
Gingival lead line OCCASIONAL Abnormality of the gingiva (HP:0000168)
Show evidence (1 reference)
PMID:6943483 SUPPORT Human Clinical
"A diagnosis of chronic lead poisoning in a mentally retarded adult with pica was initially proposed because of the presence of a "lead line" on the patient's gingiva."
Direct human clinical evidence supports Burton-line gingival changes as a classic physical finding in chronic lead poisoning.
Musculoskeletal 1
Gout OCCASIONAL Gout (HP:0001997)
Show evidence (1 reference)
PMID:8475950 SUPPORT Other
"Renal function and biopsy studies showed that lead nephropathy is a chronic tubulointerstitial renal disease with modest proteinuria which frequently presents with hyperuricemia, gout and hypertension."
Supports gout as a recognized metabolic complication of chronic lead nephropathy.
Nervous System 5
Encephalopathy OCCASIONAL Encephalopathy (HP:0001298)
Show evidence (1 reference)
PMID:29523605 SUPPORT Human Clinical
"A 2-year-old boy with a history of pica was admitted with vomiting and treated overnight for viral tonsillitis. A week later, he presented with a prolonged afebrile seizure and required intubation and ventilation."
Direct human case evidence supports severe childhood lead encephalopathy with seizure and critical neurologic deterioration.
Cognitive impairment FREQUENT Cognitive impairment (HP:0100543)
Show evidence (1 reference)
PMID:28889260 SUPPORT Other
"In utero and early life exposures to lead have been associated with lower IQ, antisocial and delinquent behaviors, and attention-deficit hyperactivity disorder."
Supports cognitive and neurobehavioral impairment as a major consequence of developmental lead exposure.
Developmental delay FREQUENT Global developmental delay (HP:0001263)
Show evidence (1 reference)
PMID:37478813 SUPPORT Human Clinical
"Exposure to lead may cause severe adverse effects such as anemia, neurologic damage, developmental disorders, and reproductive disorders."
Supports developmental delay and related developmental disorders as major pediatric consequences of lead exposure.
Behavioral changes OCCASIONAL Atypical behavior (HP:0000708)
Show evidence (1 reference)
PMID:28889260 SUPPORT Other
"In utero and early life exposures to lead have been associated with lower IQ, antisocial and delinquent behaviors, and attention-deficit hyperactivity disorder."
Supports behaviorally abnormal neurodevelopmental outcomes as a clinically important consequence of developmental lead exposure.
Peripheral neuropathy OCCASIONAL Peripheral neuropathy (HP:0009830)
Show evidence (2 references)
PMID:17405745 SUPPORT Human Clinical
"We describe a 47-year-old patient with chronic anaemia with basophilic stippling of erythrocytes, recurrent abdominal colics, discoloration of gums, sensitive polyneuropathy to the four limbs, hyperuricaemia, hepatosteatosis with raised transaminases, and a long ignored history of lead exposure..."
Direct human case evidence supports peripheral polyneuropathy as a neurologic manifestation of lead toxicity.
PMID:20142857 SUPPORT Human Clinical
"Neuropathy is one complication of lead poisoning."
Supports lead neuropathy, including occupational radial neuropathy, as a recognized complication of lead poisoning.
Constitutional 1
Abdominal pain FREQUENT Abdominal pain (HP:0002027)
Show evidence (1 reference)
PMID:17405745 SUPPORT Human Clinical
"We describe a 47-year-old patient with chronic anaemia with basophilic stippling of erythrocytes, recurrent abdominal colics, discoloration of gums, sensitive polyneuropathy to the four limbs, hyperuricaemia, hepatosteatosis with raised transaminases, and a long ignored history of lead exposure..."
Direct human case evidence supports recurrent abdominal colic as a characteristic manifestation of lead poisoning.
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Treatments

4
Exposure cessation and source control
Action: supportive care MAXO:0000950
The first intervention is removal from the lead source and prevention of ongoing exposure.
Mechanism Target:
INHIBITS Lead absorption — Source control prevents continued lead entry and lowers ongoing systemic burden.
Show evidence (1 reference)
PMID:8475950 SUPPORT Other
"While chelation therapy is safe and helpful in reversing early lead nephropathy, the best treatment is prevention."
Supports exposure prevention as the primary intervention that blocks continued toxic lead burden.
Show evidence (1 reference)
PMID:8475950 SUPPORT Other
"While chelation therapy is safe and helpful in reversing early lead nephropathy, the best treatment is prevention."
Supports exposure prevention and source removal as the foundational management strategy.
Succimer chelation
Action: chelator agent therapy MAXO:0001223
Oral succimer is used as a lead chelator, particularly in children with elevated blood lead concentrations.
Mechanism Target:
INHIBITS Systemic lead distribution — Succimer lowers circulating and soft-tissue lead burden by forming excretable complexes with lead.
Show evidence (1 reference)
PMID:1663439 SUPPORT Other
"Succimer is an orally active, heavy-metal chelating agent that forms stable, water-soluble complexes with lead; it also chelates other toxic heavy metals, such as arsenic and mercury."
Directly supports chelation of systemic lead as the proximate treatment mechanism of succimer.
Show evidence (1 reference)
PMID:1663439 SUPPORT Other
"It is a designated orphan drug that is indicated for the treatment of lead poisoning, specifically in children with blood lead concentrations higher than 45 micrograms/dL."
Directly supports succimer as an indicated chelation therapy for pediatric lead poisoning.
Calcium disodium edetate chelation
Action: chelator agent therapy MAXO:0001223
Calcium disodium EDTA chelation is used in selected patients with significant body lead burden, particularly when nephropathy is present.
Show evidence (1 reference)
PMID:8475950 SUPPORT Other
"While chelation therapy is safe and helpful in reversing early lead nephropathy, the best treatment is prevention."
Supports chelation therapy, including EDTA-based approaches discussed in lead nephropathy, as helpful in early disease.
Dimercaprol chelation
Action: chelator agent therapy MAXO:0001223
Dimercaprol is used with calcium disodium EDTA in more severely intoxicated patients, including severe acute lead poisoning and lead encephalopathy.
Show evidence (1 reference)
PMID:3540517 SUPPORT Other
"Treatment of patients with positive chelation tests involves symptomatic treatment and a course of chelation therapy utilising calcium disodium edetate in doses similar to those used for testing, and in the more severely intoxicated patient, the addition of dimercaprol in doses of 75 mg/m2 every..."
Supports dimercaprol as an established adjunct chelator for severe lead intoxication.
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Environmental Factors

10
Lead-based paint
exposure to lead link lead paint link
Deteriorating lead-based paint remains a major pediatric exposure source, especially where older housing stock is present.
Show evidence (1 reference)
PMID:28889260 SUPPORT Other
"Environmental exposures to lead, predominantly from contaminated water or lead paint chips, account for the majority of exposures to children."
Supports lead paint as a major pediatric exposure source.
Household dust
exposure to lead link household dust link
Contaminated household dust is an important secondary exposure source for children, especially in homes with legacy lead contamination.
Show evidence (1 reference)
PMID:32651990 SUPPORT Human Clinical
"Thus, house dust is an important source of lead exposure in Pakistani children."
Direct human exposure data support contaminated household dust as a meaningful pediatric lead source.
Contaminated drinking water
exposure to lead in water via ingestion link drinking water link
Lead in drinking water from aging infrastructure remains an important source of environmental exposure.
Show evidence (1 reference)
PMID:28889260 SUPPORT Other
"Environmental exposures to lead, predominantly from contaminated water or lead paint chips, account for the majority of exposures to children."
Supports contaminated water as a major exposure source.
Contaminated spices and turmeric
exposure to lead link
Lead-contaminated food products, especially locally sourced spices and turmeric, can materially increase blood lead levels in children.
Show evidence (1 reference)
PMID:36962532 SUPPORT Human Clinical
"Children in Patna, Bihar, India are exposed to multiple sources of lead, with lead levels in house dust and loose, locally sourced spices the most likely to increase blood lead levels."
Direct pediatric exposure data support contaminated spices as a foodborne source of lead exposure.
Lead-soldered food and drink cans
exposure to lead link
Historically, lead-soldered food and drink cans were an important dietary exposure source before population-level control efforts reduced this route.
Show evidence (1 reference)
PMID:9799191 SUPPORT Human Clinical
"Public health efforts have been successful in removing lead from population-wide sources such as gasoline and lead-soldered food and drink cans, but new efforts must address the difficult problem of leaded paint, especially in older houses, as well as lead in dust and soil."
Supports lead-soldered food and drink cans as a recognized historical food-related source of lead exposure.
Battery manufacture
exposure to lead link
Occupational and para-occupational lead exposure occurs in battery manufacture and related industrial handling.
Show evidence (1 reference)
PMID:40981357 SUPPORT Other
"Contemporary contamination primarily stems from mining activities, battery manufacturing, electronic waste recycling, and deteriorating infrastructure."
Supports battery manufacturing as a contemporary industrial exposure source for lead poisoning.
Mining
exposure to lead link
Mining activities remain an important occupational and community source of lead contamination and exposure.
Show evidence (1 reference)
PMID:40981357 SUPPORT Other
"Contemporary contamination primarily stems from mining activities, battery manufacturing, electronic waste recycling, and deteriorating infrastructure."
Supports mining activities as a contemporary source of lead exposure.
E-waste recycling
exposure to lead link electronic waste material link
Electronic waste recycling is an important contemporary source of lead exposure through handling and processing of contaminated materials.
Show evidence (1 reference)
PMID:40981357 SUPPORT Other
"Contemporary contamination primarily stems from mining activities, battery manufacturing, electronic waste recycling, and deteriorating infrastructure."
Supports electronic waste recycling as a contemporary source of lead exposure.
Lead-adulterated oral opium
exposure to lead link
Illicit oral opium contaminated with lead can cause major community outbreaks of lead poisoning, especially with chronic use.
Show evidence (2 references)
PMID:29531415 SUPPORT Human Clinical
"Lead-contaminated opium and heroin that has transited through the Iranian markets is a global risk and highlights a need for better monitoring of illegal drug supplies."
Supports adulterated oral opium as a documented non-occupational source of lead poisoning.
PMID:29531415 SUPPORT Human Clinical
"Analysis of an illegal opium sample showed 3.55 mg lead in 1 g opium."
Directly demonstrates lead contamination of illicit opium as the proximate exposure source in a large outbreak.
Lead-adulterated heroin
exposure to lead link
Illicit heroin contaminated with lead is a documented non-occupational exposure source that can contribute to community lead poisoning.
Show evidence (1 reference)
PMID:29531415 SUPPORT Human Clinical
"Lead-contaminated opium and heroin that has transited through the Iranian markets is a global risk and highlights a need for better monitoring of illegal drug supplies."
Supports adulterated heroin as a documented non-occupational source of lead poisoning.
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Biochemical Markers

2
Blood Lead Level (INCREASED)
Show evidence (1 reference)
PMID:37478813 SUPPORT Human Clinical
"Consequently, in 2021, the Centers for Disease Control and Prevention (CDC) reduced its blood lead reference value from 5 µg/dL to 3.5 µg/dL in pediatric patients, 1 to 5 years old."
Supports blood lead concentration as the central biomarker for diagnosis and public-health intervention.
Zinc Protoporphyrin (INCREASED)
Show evidence (1 reference)
PMID:6202140 SUPPORT Human Clinical
"Furthermore, BSC has been replaced by blood lead (since the 1940s) and zinc protoporphyrin (since the 1970s) levels for biologic monitoring of lead-exposed workers."
Supports zinc protoporphyrin as a laboratory biomarker used in monitoring lead exposure.
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Differential Diagnoses

2

Conditions with similar clinical presentations that must be differentiated from Lead Poisoning:

Cadmium Poisoning MONDO:0043523
Overlapping Features Cadmium poisoning overlaps with lead toxicity through chronic occupational exposure and proximal tubular nephrotoxicity, but the renal phenotype and associated laboratory findings differ.
Distinguishing Features
  • Cadmium causes Fanconi syndrome with low-molecular-weight proteinuria and beta2-microglobulinuria
  • Lead nephropathy instead is associated with hyperuricemia, gout, and hypertension
  • Proximal tubule nuclear inclusion bodies are characteristic of early lead nephropathy
Show evidence (2 references)
PMID:19106433 SUPPORT Other
"Cadmium in sufficient cumulative dosage leads to the production of the Fanconi syndrome, a generalized proximal tubular reabsorptive defect thought to be related to inhibition of both ATP production and Na-K-ATPase activity. On the other hand, lead accumulation in the proximal tubule leads to..."
Directly contrasts cadmium and lead nephrotoxicity, supporting cadmium poisoning as a major differential diagnosis.
PMID:19106433 SUPPORT Other
"Beta2-microglobulinuria is not found in lead nephropathy."
Supports beta2-microglobulinuria as a distinguishing feature favoring cadmium over lead toxicity.
Arsenic Poisoning
Overlapping Features Arsenic poisoning can overlap with lead poisoning through gastrointestinal symptoms and neuropathy, but chronic arsenic exposure more strongly features characteristic skin findings and carcinogenic sequelae.
Distinguishing Features
  • Chronic arsenic exposure causes hyperpigmentation and palmoplantar keratoses
  • Arsenic exposure is strongly associated with skin, lung, and bladder cancer
  • Lead poisoning more characteristically shows basophilic stippling, lead-line gingival changes, and ALAD inhibition
Show evidence (2 references)
PMID:28005215 SUPPORT Other
"It is proven fact that uptake of inorganic As for a long period can lead to chronic As poisoning and a variety of adverse health effects such as skin, lung and bladder cancer, in addition to cardiovascular diseases, diabetes and gastrointestinal symptoms."
Supports the chronic dermatologic and carcinogenic profile that distinguishes arsenic poisoning from lead toxicity.
PMID:17405745 SUPPORT Human Clinical
"We describe a 47-year-old patient with chronic anaemia with basophilic stippling of erythrocytes, recurrent abdominal colics, discoloration of gums, sensitive polyneuropathy to the four limbs, hyperuricaemia, hepatosteatosis with raised transaminases, and a long ignored history of lead exposure..."
Supports the lead-specific constellation of basophilic stippling, abdominal colic, and occupational exposure history.
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Related Datasets

2
Methodoligies for identifying lead toxicity geo:GSE37567
Human PBMC transcriptomic dataset used to quantify the impact of lead on cytokine production and gene expression in peripheral blood mononuclear cells.
human MICROARRAY n=102
peripheral blood mononuclear cells link
Conditions: lead-associated PBMC cytokine and gene-expression profiling
Show evidence (1 reference)
GEO:GSE37567 SUPPORT In Vitro
"Quantifying impact of lead on cytokine production and gene expression in PBMCs"
Supports this dataset as a lead-relevant PBMC transcriptomic resource.
Early life Lead exposure causes distinct gender specific changes in the DNA methylation profile of DNA extracted from dried blood spots geo:GSE60598
Human methylation dataset from dried blood spots in a Detroit pediatric cohort, profiling sex-specific epigenomic effects of early-life lead exposure.
human METHYLATION n=43
dried blood spots
Conditions: early-life lead exposure pediatric blood-spot methylation profiling
Exposures: lead exposure link
Show evidence (1 reference)
GEO:GSE60598 SUPPORT Human Clinical
"Study of influence of gender and Lead(Pb) exposure on DNA methylation for whole blood measured in dried blood spots for a Detroit cohort of child between the age of 3 months to 5years"
Supports this dataset as a pediatric human epigenomic resource for lead exposure effects.
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Clinical Trials

3
NCT00342849 PHASE_III COMPLETED
Treatment of Lead-Exposed Children (TLC) was a randomized, double-blind, placebo-controlled multicenter trial comparing succimer chelation with placebo in lead-exposed children, with follow-up focused on IQ, neuropsychological function, behavior, growth, and blood pressure.
Target Phenotypes: cognitive impairment ↗
Show evidence (2 references)
clinicaltrials:NCT00342849 SUPPORT Human Clinical
"The Treatment of Lead-Exposed Children (TLC) clinical trial compared the effect of lead chelation with succimer to placebo therapy."
Supports a definitive randomized therapeutic trial of succimer in lead-exposed children.
clinicaltrials:NCT00342849 SUPPORT Human Clinical
"The study was designed to test outcomes in IQ, neuropsychological function, behavior, physical growth and blood pressure three years after initiation of treatment."
Supports neurocognitive and physiologic outcome assessment relevant to lead toxicity.
NCT01573013 NOT_APPLICABLE COMPLETED
Interventional study in Morocco evaluating whether iron fortification, with or without NaFeEDTA, can reduce blood lead levels and improve growth, motor performance, cognition, and iron status in lead-exposed children.
Target Phenotypes: anemia ↗ cognitive impairment ↗
Show evidence (2 references)
clinicaltrials:NCT01573013 SUPPORT Human Clinical
"In a follow-on intervention study, the effect of iron fortification with and without NaEDTA on blood lead levels in lead-exposed children will be evaluated; and the relative impact of these two strategies on child growth, motor and cognitive test performance will be compared."
Supports an interventional trial targeting both lead burden and functional outcomes in exposed children.
clinicaltrials:NCT01573013 SUPPORT Human Clinical
"This study will investigate the potential use of iron fortification to not only combat anemia but also reduce body lead burden in lead-exposed populations; it specifically investigates whether iron fortification with NaFeEDTA could have additional beneficial effects to iron alone."
Supports anemia-focused nutritional intervention as part of lead poisoning management research.
NCT05507021 NOT_APPLICABLE COMPLETED
Randomized, placebo-controlled pilot trial evaluating Lactobacillus plantarum DSM 33464 as a biologic intervention to reduce blood lead levels in young women of child-bearing age.
Target Phenotypes: anemia ↗ cognitive impairment ↗
Show evidence (2 references)
clinicaltrials:NCT05507021 SUPPORT Human Clinical
"We hypothesize that Lactobacillus Plantarum DSM 33464 reduce lead levels."
Supports a completed pilot interventional study aimed at lowering blood lead burden.
clinicaltrials:NCT05507021 SUPPORT Human Clinical
"From that pool of subjects, 40 healthy women aged 18 to 40 years will participate in this randomized, placebo controlled pilot clinical trial."
Supports the interventional randomized design of this lead-reduction trial.
{ }

Source YAML

click to show 
name: Lead Poisoning
creation_date: "2026-03-10T20:45:26Z"
updated_date: "2026-03-10T23:12:33Z"
category: Environmental
categories:
- Toxic Exposure Disorder
- Heavy Metal Poisoning
- Environmental Health Disorder
synonyms:
- plumbism
- saturnism
description: >-
  Lead poisoning is a toxic condition caused by acute or chronic exposure to
  lead, a non-essential heavy metal encountered through deteriorating lead-based
  paint, contaminated drinking water, battery manufacture and recycling,
  mining and smelting, electronic waste, and other occupational or environmental
  sources. Children are especially vulnerable because lead disrupts nervous
  system development even at relatively low blood lead concentrations. Lead
  toxicity reflects calcium mimicry, inhibition of heme biosynthesis, oxidative
  stress, mitochondrial dysfunction, and chronic accumulation in bone and kidney.
  Clinical manifestations include abdominal pain, constipation, anemia,
  cognitive impairment, peripheral neuropathy, nephropathy, and hypertension.
disease_term:
  preferred_term: lead poisoning
  term:
    id: MONDO:0018019
    label: lead poisoning
mappings:
  mondo_mappings:
  - term:
      id: MONDO:0018019
      label: lead poisoning
    mapping_predicate: skos:exactMatch
    mapping_source: MONDO
    mapping_justification: Primary MONDO disease identifier for this lead poisoning entry.
definitions:
- name: Clinical multisystem toxicity case definition for lead poisoning
  definition_type: CASE_DEFINITION
  description: >-
    Lead poisoning is a toxic disorder caused by exposure to the non-essential
    heavy metal lead, with multisystem adverse effects and no safe exposure
    threshold identified.
  scope: Disease-level clinical framing across acute and chronic lead exposure
  evidence:
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Lead (Pb) is a non-essential, toxic heavy metal with no known biological function that has caused widespread environmental contamination throughout human history."
    explanation: Supports the core disease framing as toxic illness caused by exposure to a non-essential heavy metal.
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Pb toxicity represents one of the most persistent environmental health challenges, with no safe exposure threshold identified."
    explanation: Supports inclusion of the no-safe-threshold concept in the disease-level definition.
- name: Practical diagnostic definition for clinically significant lead exposure
  definition_type: DIAGNOSTIC_CRITERIA
  description: >-
    Clinical definition of lead poisoning relies on demonstration of elevated
    venous blood lead concentration in the relevant clinical context, with
    body-burden assessment needed when chronic lead nephropathy is suspected.
  scope: Clinical diagnosis and complication-focused workup in exposed patients
  evidence:
  - reference: PMID:37478813
    reference_title: "Trends in Blood Lead Levels Quantified by ICP-MS: A Reference Laboratory Retrospective Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Consequently, in 2021, the Centers for Disease Control and Prevention (CDC) reduced its blood lead reference value from 5 µg/dL to 3.5 µg/dL in pediatric patients, 1 to 5 years old."
    explanation: Supports venous blood lead concentration as the central contemporary clinical benchmark for defining significant pediatric lead exposure.
  - reference: PMID:8475950
    reference_title: "Lead nephropathy, gout, and hypertension."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Only evaluation of body lead stores by either the EDTA lead mobilization test or by x-ray fluorescence is helpful in diagnosing lead nephropathy."
    explanation: Supports refinement of the clinical definition in chronic nephropathy, where blood lead alone may not capture retained body burden.
parents:
- heavy metal poisoning
has_subtypes:
- name: Acute Lead Poisoning
  description: >-
    Acute lead poisoning follows high-dose ingestion or inhalation and may
    present with severe abdominal pain, vomiting, encephalopathy, hemolysis,
    acute kidney injury, and rapidly rising blood lead concentrations.
  evidence:
  - reference: PMID:3103564
    reference_title: "Acute-subacute lead poisoning. Clinical findings and comparative study of diagnostic tests."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A prospective study of an epidemic outbreak of acute lead poisoning characterized by unusual clinical and analytic manifestations was carried out."
    explanation: Directly supports acute lead poisoning as a clinically recognizable subtype.
- name: Chronic Lead Poisoning
  description: >-
    Chronic lead poisoning results from sustained lower-level exposure with
    progressive neurocognitive effects, constipation, anemia, peripheral
    neuropathy, chronic kidney disease, and hypertension. Bone stores become a
    long-term endogenous reservoir for recurrent lead release.
  evidence:
  - reference: PMID:1030853
    reference_title: "Chronic industrial exposure to lead in 63 subjects. I. Clinical and erythrokinetic findings."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Clinical, biochemical, haematological and erythrokinetic studies were performed on 63 adult males with prolonged lead exposure."
    explanation: Supports chronic lead poisoning as a distinct syndrome of prolonged exposure with multisystem clinical findings.
pathophysiology:
- name: Lead absorption
  description: >-
    Lead enters the body through gastrointestinal and respiratory absorption.
  biological_processes:
  - preferred_term: transmembrane transport
    modifier: ABNORMAL
    term:
      id: GO:0055085
      label: transmembrane transport
  downstream:
  - target: Systemic lead distribution
    description: Absorbed lead enters the bloodstream and is distributed to soft tissues and bone.
    evidence:
    - reference: PMID:40981357
      reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Pb enters organisms through multiple pathways and causes severe health impacts across all biological systems, with particularly devastating neurodevelopmental and bone effects in children and cardiovascular and reproductive consequences in adults."
      explanation: Supports transition from lead entry into the body to systemic tissue exposure.
  evidence:
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Pb enters organisms through multiple pathways and causes severe health impacts across all biological systems, with particularly devastating neurodevelopmental and bone effects in children and cardiovascular and reproductive consequences in adults."
    explanation: Supports lead entry through multiple exposure pathways and its capacity to reach multiple organ systems.
- name: Systemic lead distribution
  description: >-
    Absorbed lead circulates systemically and persists in biologic tissues,
    allowing redistribution into bone, erythroid tissues, neurons, and kidney.
  downstream:
  - target: Bone sequestration of lead
    description: Systemically absorbed lead is progressively redistributed into bone stores.
    evidence:
    - reference: PMID:40981357
      reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "The metal demonstrates remarkable persistence in biological systems, with approximately 90% of it stored in bone tissue for decades, mimicking calcium due to its similar ionic properties."
      explanation: Supports redistribution of absorbed lead into long-lived bone stores.
  - target: Inhibition of delta-aminolevulinic acid dehydratase
    description: Circulating lead reaches erythroid tissues and inhibits a key heme biosynthetic enzyme.
    evidence:
    - reference: PMID:3442386
      reference_title: "delta-Aminolevulinic acid dehydratase isozymes and lead toxicity."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "ALAD is a zinc metalloenzyme whose inhibition by lead is the first and most sensitive indicator of lead exposure and whose decreased activity has been implicated in the pathogenesis of lead poisoning."
      explanation: Supports direct inhibition of ALAD after lead exposure.
  - target: Calcium mimicry in neuronal signaling
    description: Lead acts as an ionic mimic of calcium in intracellular signaling pathways.
    evidence:
    - reference: PMID:8247416
      reference_title: "Evidence that lead acts as a calcium substitute in second messenger metabolism."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Our investigations of the ability of lead to substitute for calcium in several intracellular regulatory events are reviewed in the context of the neurotoxicity produced by this heavy metal."
      explanation: Supports the transition from lead exposure to calcium-mimicry-mediated signaling disruption.
  - target: Proximal tubular lead accumulation
    description: Chronic systemic exposure leads to progressive renal cortical accumulation.
    evidence:
    - reference: PMID:2650022
      reference_title: "Mechanisms of lead and cadmium nephrotoxicity."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Exposure to lead results in accumulation in proximal renal tubular lining cells in the form of morphologically discernible inclusion bodies which are lead-protein complexes."
      explanation: Supports proximal tubular accumulation as a direct downstream consequence of lead exposure.
  evidence:
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The metal demonstrates remarkable persistence in biological systems, with approximately 90% of it stored in bone tissue for decades, mimicking calcium due to its similar ionic properties."
    explanation: Supports systemic persistence and redistribution of lead into long-lived tissue reservoirs.
- name: Bone sequestration of lead
  description: >-
    Most retained lead is deposited in bone, where it replaces calcium within
    mineralized tissue and serves as a long-term endogenous source of ongoing
    exposure during bone turnover.
  cell_types:
  - preferred_term: osteoblast
    term:
      id: CL:0000062
      label: osteoblast
  biological_processes:
  - preferred_term: calcium ion homeostasis
    modifier: ABNORMAL
    term:
      id: GO:0055074
      label: calcium ion homeostasis
  evidence:
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "The metal demonstrates remarkable persistence in biological systems, with approximately 90% of it stored in bone tissue for decades, mimicking calcium due to its similar ionic properties."
    explanation: Supports bone sequestration as a defining kinetic feature of lead poisoning.
  - reference: PMID:20643234
    reference_title: "The effect of lead on bone mineral properties from female adult C57/BL6 mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "These data show that lead increases bone turnover resulting in weaker cortical bone in adult female mice and suggest that lead may exacerbate bone loss and osteoporosis in the elderly."
    explanation: Mouse data support direct adverse skeletal consequences of chronic bone lead deposition.
- name: Inhibition of delta-aminolevulinic acid dehydratase
  description: >-
    Lead inhibits delta-aminolevulinic acid dehydratase (ALAD), a zinc-dependent
    heme biosynthetic enzyme. This is an early and sensitive biochemical lesion
    of lead exposure and contributes to defective heme production.
  cell_types:
  - preferred_term: erythrocyte
    term:
      id: CL:0000232
      label: erythrocyte
  biological_processes:
  - preferred_term: heme biosynthetic process
    modifier: DECREASED
    term:
      id: GO:0006783
      label: heme biosynthetic process
  downstream:
  - target: Anemia
    description: Impaired heme synthesis contributes to reduced erythrocyte function and clinical anemia.
    evidence:
    - reference: PMID:3442386
      reference_title: "delta-Aminolevulinic acid dehydratase isozymes and lead toxicity."
      supports: PARTIAL
      evidence_source: HUMAN_CLINICAL
      snippet: "ALAD is a zinc metalloenzyme whose inhibition by lead is the first and most sensitive indicator of lead exposure and whose decreased activity has been implicated in the pathogenesis of lead poisoning."
      explanation: Supports defective heme biosynthesis as a core pathogenic lesion that contributes to lead-associated anemia.
    - reference: PMID:33505133
      reference_title: "Activated Carbon Fabric Mask Reduces Lead Absorption and Improves the Heme Biosynthesis and Hematological Parameters of Battery Manufacturing Workers."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "Two months using ACF mask reduces the blood lead level and improves the δ-ALDH activity and hematological parameters, decreases the urinary excretion of δ-ALA, PBG of battery manufacturing workers."
      explanation: Human worker data support a downstream relationship between recovery of ALAD-linked heme biosynthesis and improvement in hematologic parameters, consistent with ALAD inhibition contributing to anemia.
  evidence:
  - reference: PMID:3442386
    reference_title: "delta-Aminolevulinic acid dehydratase isozymes and lead toxicity."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "ALAD is a zinc metalloenzyme whose inhibition by lead is the first and most sensitive indicator of lead exposure and whose decreased activity has been implicated in the pathogenesis of lead poisoning."
    explanation: Directly supports ALAD inhibition as a central biochemical mechanism in lead toxicity.
- name: Erythrocyte pyrimidine 5'-nucleotidase deficiency
  description: >-
    Lead intoxication causes an acquired erythrocyte pyrimidine 5'-nucleotidase
    deficiency, leading to abnormal pyrimidine nucleotide handling and
    basophilic stippling.
  cell_types:
  - preferred_term: erythrocyte
    term:
      id: CL:0000232
      label: erythrocyte
  biological_processes:
  - preferred_term: pyrimidine-containing compound biosynthetic process
    modifier: ABNORMAL
    term:
      id: GO:0072528
      label: pyrimidine-containing compound biosynthetic process
  downstream:
  - target: Hemolytic erythrocyte injury
    description: Lead-induced erythrocyte enzyme dysfunction contributes to downstream hemolytic injury.
    evidence:
    - reference: PMID:965496
      reference_title: "Lead poisoning: association with hemolytic anemia, basophilic stippling, erythrocyte pyrimidine 5'-nucleotidase deficiency, and intraerythrocytic accumulation of pyrimidines."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The findings indicate that the hemolytic anemia and increased basophilic stippling characteristic of certain cases of lead intoxication may share a common etiology with essentially identical features of the genetically determined disorder."
      explanation: Supports a downstream relationship between pyrimidine 5'-nucleotidase deficiency and hemolytic erythrocyte injury.
  evidence:
  - reference: PMID:965496
    reference_title: "Lead poisoning: association with hemolytic anemia, basophilic stippling, erythrocyte pyrimidine 5'-nucleotidase deficiency, and intraerythrocytic accumulation of pyrimidines."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lead intoxication is accompanied by an acquired deficiency of erythrocyte pryimidine-specific, 5'-nucleotidase."
    explanation: Supports lead-induced erythrocyte enzymatic injury as a mechanism of hematologic toxicity.
- name: Hemolytic erythrocyte injury
  description: >-
    Lead-associated erythrocyte injury increases hemolysis and contributes to
    clinically significant anemia.
  cell_types:
  - preferred_term: erythrocyte
    term:
      id: CL:0000232
      label: erythrocyte
  downstream:
  - target: Anemia
    description: Hemolytic erythrocyte injury contributes to hemolytic anemia in lead intoxication.
    evidence:
    - reference: PMID:965496
      reference_title: "Lead poisoning: association with hemolytic anemia, basophilic stippling, erythrocyte pyrimidine 5'-nucleotidase deficiency, and intraerythrocytic accumulation of pyrimidines."
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: "The findings indicate that the hemolytic anemia and increased basophilic stippling characteristic of certain cases of lead intoxication may share a common etiology with essentially identical features of the genetically determined disorder."
      explanation: Directly supports hemolytic erythrocyte injury as a downstream cause of anemia in lead intoxication.
  evidence:
  - reference: PMID:965496
    reference_title: "Lead poisoning: association with hemolytic anemia, basophilic stippling, erythrocyte pyrimidine 5'-nucleotidase deficiency, and intraerythrocytic accumulation of pyrimidines."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The findings indicate that the hemolytic anemia and increased basophilic stippling characteristic of certain cases of lead intoxication may share a common etiology with essentially identical features of the genetically determined disorder."
    explanation: Supports hemolytic erythrocyte injury as a distinct hematologic event in lead intoxication.
- name: Calcium mimicry in neuronal signaling
  description: >-
    Lead acts as a calcium substitute in intracellular signaling, perturbing
    calcium-dependent neuronal regulatory pathways.
  cell_types:
  - preferred_term: neuron
    term:
      id: CL:0000540
      label: neuron
  biological_processes:
  - preferred_term: calcium ion homeostasis
    modifier: ABNORMAL
    term:
      id: GO:0055074
      label: calcium ion homeostasis
  downstream:
  - target: Protein kinase C dysregulation
    description: Lead substitution for calcium perturbs second-messenger signaling and promotes downstream protein kinase C dysregulation.
    evidence:
    - reference: PMID:8247416
      reference_title: "Evidence that lead acts as a calcium substitute in second messenger metabolism."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Taken together these studies implicate second messenger metabolism and protein kinase activation as potential sites for the disruptive action of lead upon nervous system function."
      explanation: Supports downstream protein kinase C dysregulation after lead-induced disturbance of calcium-dependent intracellular signaling.
  evidence:
  - reference: PMID:8247416
    reference_title: "Evidence that lead acts as a calcium substitute in second messenger metabolism."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Our investigations of the ability of lead to substitute for calcium in several intracellular regulatory events are reviewed in the context of the neurotoxicity produced by this heavy metal."
    explanation: Supports calcium mimicry as a distinct upstream mechanism of lead neurotoxicity.
- name: Protein kinase C dysregulation
  description: >-
    Lead-induced disturbance of second-messenger signaling alters protein
    kinase C activation and other calcium-regulated neuronal signaling outputs.
  cell_types:
  - preferred_term: neuron
    term:
      id: CL:0000540
      label: neuron
  downstream:
  - target: Cognitive impairment
    description: Dysregulated neuronal signaling contributes to impaired cognition and neurodevelopment.
    evidence:
    - reference: PMID:28889260
      reference_title: "Developmental Neurotoxicity of Lead."
      supports: PARTIAL
      evidence_source: OTHER
      snippet: "In utero and early life exposures to lead have been associated with lower IQ, antisocial and delinquent behaviors, and attention-deficit hyperactivity disorder."
      explanation: Supports cognitive impairment as a downstream clinical manifestation of lead neurotoxicity, although the abstract does not isolate protein kinase C signaling specifically.
    - reference: PMID:10215516
      reference_title: "Protein kinase C in rat brain is altered by developmental lead exposure."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "The absence of learning-related redistribution of hippocampal protein kinase C (PKC) has been correlated with impairment of learning performance induced by developmental lead (Pb) exposure."
      explanation: Rat data directly support a downstream link between lead-induced PKC dysregulation and impaired learning performance.
    - reference: PMID:9559103
      reference_title: "Developmental lead exposure alters the distribution of protein kinase C activity in the rat hippocampus."
      supports: SUPPORT
      evidence_source: MODEL_ORGANISM
      snippet: "This study indicates that chronic Pb exposure during development influences hippocampal PKC activity and distribution. These changes may be involved in the subclinical neurotoxicity of chronic Pb exposure in young children."
      explanation: Independent developmental rat data support abnormal hippocampal PKC signaling as a mechanism contributing to downstream neurocognitive toxicity.
  evidence:
  - reference: PMID:8247416
    reference_title: "Evidence that lead acts as a calcium substitute in second messenger metabolism."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Taken together these studies implicate second messenger metabolism and protein kinase activation as potential sites for the disruptive action of lead upon nervous system function."
    explanation: Supports protein kinase activation dysregulation as a distinct downstream neuronal signaling event in lead toxicity.
- name: Mitochondrial dysfunction
  description: >-
    Lead poisoning perturbs mitochondrial function across multiple organ
    systems, contributing to cellular energy failure and tissue injury.
  biological_processes:
  - preferred_term: mitochondrion organization
    modifier: ABNORMAL
    term:
      id: GO:0007005
      label: mitochondrion organization
  evidence:
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "On a molecular level, Pb disrupts cellular processes through ion mimicry, replacing essential metals in enzymes and proteins and leading to mitochondrial dysfunction, oxidative stress, DNA damage, and epigenetic modifications."
    explanation: Supports mitochondrial dysfunction as a distinct downstream mechanism of lead toxicity.
- name: Oxidative stress response
  description: >-
    Lead exposure increases oxidative stress signaling and contributes to
    multisystem cellular injury.
  biological_processes:
  - preferred_term: response to oxidative stress
    modifier: INCREASED
    term:
      id: GO:0006979
      label: response to oxidative stress
  evidence:
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "On a molecular level, Pb disrupts cellular processes through ion mimicry, replacing essential metals in enzymes and proteins and leading to mitochondrial dysfunction, oxidative stress, DNA damage, and epigenetic modifications."
    explanation: Supports oxidative stress as a distinct downstream mechanism of lead toxicity.
- name: Proximal tubular lead accumulation
  description: >-
    Lead accumulates in proximal renal tubular cells, where it forms inclusion
    bodies and produces potentially reversible proximal tubular dysfunction in
    acute toxicity.
  cell_types:
  - preferred_term: proximal tubule cell
    term:
      id: CL:0002306
      label: epithelial cell of proximal tubule
  biological_processes:
  - preferred_term: renal absorption
    modifier: ABNORMAL
    term:
      id: GO:0070293
      label: renal absorption
  downstream:
  - target: Chronic tubulointerstitial nephropathy
    description: Persistent proximal tubular lead injury progresses to chronic tubulointerstitial renal disease.
    evidence:
    - reference: PMID:9300927
      reference_title: "Renal effects of environmental and occupational lead exposure."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Chronic occupational exposure to lead, or consumption of illicit alcohol adulterated with lead, has also been linked to a high incidence of renal dysfunction, which is characterized by glomerular and tubulointerstitial changes resulting in chronic renal failure, hypertension, hyperuricemia, and gout."
      explanation: Supports chronic tubulointerstitial renal disease as a downstream outcome of persistent lead-related renal injury.
  evidence:
  - reference: PMID:2650022
    reference_title: "Mechanisms of lead and cadmium nephrotoxicity."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Exposure to lead results in accumulation in proximal renal tubular lining cells in the form of morphologically discernible inclusion bodies which are lead-protein complexes."
    explanation: Supports proximal tubular accumulation as the initial renal lesion of lead nephrotoxicity.
  - reference: PMID:2650022
    reference_title: "Mechanisms of lead and cadmium nephrotoxicity."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Acute nephrotoxicity consists of proximal tubular dysfunction and can be reversed by treatment with chelating agents."
    explanation: Supports proximal tubular dysfunction as the dominant acute renal consequence of lead accumulation.
- name: Chronic tubulointerstitial nephropathy
  description: >-
    Chronic lead nephrotoxicity is a tubulointerstitial renal disease marked by
    interstitial fibrosis, progressive nephron loss, and associated
    hyperuricemia, gout, and hypertension.
  cell_types:
  - preferred_term: proximal tubule cell
    term:
      id: CL:0002306
      label: epithelial cell of proximal tubule
  downstream:
  - target: Chronic kidney disease
    description: Progressive nephron loss in chronic lead nephropathy produces persistent chronic kidney disease.
    evidence:
    - reference: PMID:9300927
      reference_title: "Renal effects of environmental and occupational lead exposure."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Chronic occupational exposure to lead, or consumption of illicit alcohol adulterated with lead, has also been linked to a high incidence of renal dysfunction, which is characterized by glomerular and tubulointerstitial changes resulting in chronic renal failure, hypertension, hyperuricemia, and gout."
      explanation: Supports chronic kidney disease as a downstream consequence of chronic lead nephropathy.
  - target: Gout
    description: Lead-related renal dysfunction promotes hyperuricemia and gout.
    evidence:
    - reference: PMID:8475950
      reference_title: "Lead nephropathy, gout, and hypertension."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Renal function and biopsy studies showed that lead nephropathy is a chronic tubulointerstitial renal disease with modest proteinuria which frequently presents with hyperuricemia, gout and hypertension."
      explanation: Directly supports gout as a downstream clinical consequence of chronic lead nephropathy.
  - target: Hypertension
    description: Chronic lead nephropathy frequently presents with hypertension.
    evidence:
    - reference: PMID:8475950
      reference_title: "Lead nephropathy, gout, and hypertension."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Renal function and biopsy studies showed that lead nephropathy is a chronic tubulointerstitial renal disease with modest proteinuria which frequently presents with hyperuricemia, gout and hypertension."
      explanation: Directly supports hypertension as a downstream clinical consequence of chronic lead nephropathy.
  evidence:
  - reference: PMID:2650022
    reference_title: "Mechanisms of lead and cadmium nephrotoxicity."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Chronic lead nephrotoxicity consists of interstitial fibrosis and progressive nephron loss, azotaemia and renal failure. Potential complications of lead nephropathy include gout and hypertension."
    explanation: Supports the chronic fibrosing renal phenotype and its hypertensive complication.
  - reference: PMID:8475950
    reference_title: "Lead nephropathy, gout, and hypertension."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Renal function and biopsy studies showed that lead nephropathy is a chronic tubulointerstitial renal disease with modest proteinuria which frequently presents with hyperuricemia, gout and hypertension."
    explanation: Confirms the clinical pattern of chronic tubulointerstitial nephropathy in lead poisoning.
phenotypes:
- category: Gastrointestinal
  name: Abdominal pain
  frequency: FREQUENT
  description: >-
    Cramping abdominal pain or lead colic, particularly in more symptomatic
    acute or chronic intoxication.
  phenotype_term:
    preferred_term: abdominal pain
    term:
      id: HP:0002027
      label: Abdominal pain
  evidence:
  - reference: PMID:17405745
    reference_title: "Anaemia and abdominal pain due to occupational lead poisoning."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We describe a 47-year-old patient with chronic anaemia with basophilic stippling of erythrocytes, recurrent abdominal colics, discoloration of gums, sensitive polyneuropathy to the four limbs, hyperuricaemia, hepatosteatosis with raised transaminases, and a long ignored history of lead exposure in a battery recycling plant."
    explanation: Direct human case evidence supports recurrent abdominal colic as a characteristic manifestation of lead poisoning.
- category: Gastrointestinal
  name: Constipation
  frequency: FREQUENT
  description: >-
    Reduced bowel motility and constipation are common gastrointestinal
    manifestations of lead toxicity.
  phenotype_term:
    preferred_term: constipation
    term:
      id: HP:0002019
      label: Constipation
  evidence:
  - reference: PMID:29531415
    reference_title: "Lead poisoning outbreak among opium users in the Islamic Republic of Iran, 2016-2017."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In February 2016, we noticed a steep increase in the numbers of oral opium users referred to our poison treatment centre with abdominal pain, anaemia and constipation."
    explanation: Outbreak data provide direct human clinical support for constipation as a common presenting feature of lead poisoning.
- category: Hematologic
  name: Anemia
  frequency: FREQUENT
  description: >-
    Lead poisoning causes anemia through impaired heme synthesis and, in some
    cases, hemolytic injury.
  phenotype_term:
    preferred_term: anemia
    term:
      id: HP:0001903
      label: Anemia
  evidence:
  - reference: PMID:37478813
    reference_title: "Trends in Blood Lead Levels Quantified by ICP-MS: A Reference Laboratory Retrospective Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Exposure to lead may cause severe adverse effects such as anemia, neurologic damage, developmental disorders, and reproductive disorders."
    explanation: Supports anemia as a major adverse clinical effect of lead exposure.
  - reference: PMID:965496
    reference_title: "Lead poisoning: association with hemolytic anemia, basophilic stippling, erythrocyte pyrimidine 5'-nucleotidase deficiency, and intraerythrocytic accumulation of pyrimidines."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The findings indicate that the hemolytic anemia and increased basophilic stippling characteristic of certain cases of lead intoxication may share a common etiology with essentially identical features of the genetically determined disorder."
    explanation: Supports hemolytic anemia as a clinically important hematologic manifestation of lead intoxication.
- category: Nervous System
  name: Encephalopathy
  frequency: OCCASIONAL
  description: >-
    Severe acute lead poisoning, especially in children, can cause life-
    threatening lead encephalopathy with seizures, altered mental status, and
    raised intracranial pressure.
  phenotype_term:
    preferred_term: encephalopathy
    term:
      id: HP:0001298
      label: Encephalopathy
  evidence:
  - reference: PMID:29523605
    reference_title: "Lead in a case of encephalopathy."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A 2-year-old boy with a history of pica was admitted with vomiting and treated overnight for viral tonsillitis. A week later, he presented with a prolonged afebrile seizure and required intubation and ventilation."
    explanation: Direct human case evidence supports severe childhood lead encephalopathy with seizure and critical neurologic deterioration.
- category: Nervous System
  name: Cognitive impairment
  frequency: FREQUENT
  description: >-
    Lead exposure, especially during development, is associated with lasting
    impairment in cognition and intellectual function.
  phenotype_term:
    preferred_term: cognitive impairment
    term:
      id: HP:0100543
      label: Cognitive impairment
  evidence:
  - reference: PMID:28889260
    reference_title: "Developmental Neurotoxicity of Lead."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "In utero and early life exposures to lead have been associated with lower IQ, antisocial and delinquent behaviors, and attention-deficit hyperactivity disorder."
    explanation: Supports cognitive and neurobehavioral impairment as a major consequence of developmental lead exposure.
- category: Nervous System
  name: Developmental delay
  frequency: FREQUENT
  description: >-
    Early-life lead exposure disrupts neurodevelopment and is associated with
    developmental delay and broader developmental disorders in children.
  phenotype_term:
    preferred_term: developmental delay
    term:
      id: HP:0001263
      label: Global developmental delay
  evidence:
  - reference: PMID:37478813
    reference_title: "Trends in Blood Lead Levels Quantified by ICP-MS: A Reference Laboratory Retrospective Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Exposure to lead may cause severe adverse effects such as anemia, neurologic damage, developmental disorders, and reproductive disorders."
    explanation: Supports developmental delay and related developmental disorders as major pediatric consequences of lead exposure.
- category: Nervous System
  name: Behavioral changes
  frequency: OCCASIONAL
  description: >-
    Developmental lead exposure is associated with behavioral abnormalities,
    including attention-related and antisocial behavioral changes.
  phenotype_term:
    preferred_term: behavioral changes
    term:
      id: HP:0000708
      label: Atypical behavior
  evidence:
  - reference: PMID:28889260
    reference_title: "Developmental Neurotoxicity of Lead."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "In utero and early life exposures to lead have been associated with lower IQ, antisocial and delinquent behaviors, and attention-deficit hyperactivity disorder."
    explanation: Supports behaviorally abnormal neurodevelopmental outcomes as a clinically important consequence of developmental lead exposure.
- category: Nervous System
  name: Peripheral neuropathy
  frequency: OCCASIONAL
  description: >-
    Lead neuropathy is classically motor-predominant and may present with wrist
    drop or radial palsy.
  phenotype_term:
    preferred_term: peripheral neuropathy
    term:
      id: HP:0009830
      label: Peripheral neuropathy
  evidence:
  - reference: PMID:17405745
    reference_title: "Anaemia and abdominal pain due to occupational lead poisoning."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We describe a 47-year-old patient with chronic anaemia with basophilic stippling of erythrocytes, recurrent abdominal colics, discoloration of gums, sensitive polyneuropathy to the four limbs, hyperuricaemia, hepatosteatosis with raised transaminases, and a long ignored history of lead exposure in a battery recycling plant."
    explanation: Direct human case evidence supports peripheral polyneuropathy as a neurologic manifestation of lead toxicity.
  - reference: PMID:20142857
    reference_title: "Radial neuropathy due to occupational lead exposure: Phenotypic and electrophysiological characteristics of five patients."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Neuropathy is one complication of lead poisoning."
    explanation: Supports lead neuropathy, including occupational radial neuropathy, as a recognized complication of lead poisoning.
- category: Cardiovascular
  name: Hypertension
  frequency: OCCASIONAL
  description: >-
    Chronic lead nephropathy and persistent lead burden are associated with
    systemic hypertension.
  phenotype_term:
    preferred_term: hypertension
    term:
      id: HP:0000822
      label: Hypertension
  evidence:
  - reference: PMID:8475950
    reference_title: "Lead nephropathy, gout, and hypertension."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Renal function and biopsy studies showed that lead nephropathy is a chronic tubulointerstitial renal disease with modest proteinuria which frequently presents with hyperuricemia, gout and hypertension."
    explanation: Supports hypertension as a common complication of chronic lead nephropathy.
- category: Renal
  name: Chronic kidney disease
  frequency: OCCASIONAL
  description: >-
    Chronic occupational or environmental lead exposure can produce
    progressive chronic kidney disease through tubulointerstitial nephropathy.
  phenotype_term:
    preferred_term: chronic kidney disease
    term:
      id: HP:0012622
      label: Chronic kidney disease
  evidence:
  - reference: PMID:9300927
    reference_title: "Renal effects of environmental and occupational lead exposure."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Chronic occupational exposure to lead, or consumption of illicit alcohol adulterated with lead, has also been linked to a high incidence of renal dysfunction, which is characterized by glomerular and tubulointerstitial changes resulting in chronic renal failure, hypertension, hyperuricemia, and gout."
    explanation: Supports chronic kidney disease as a clinically important manifestation of chronic lead nephrotoxicity.
- category: Metabolic
  name: Gout
  frequency: OCCASIONAL
  description: >-
    Chronic lead nephropathy can impair urate handling and contribute to gout.
  phenotype_term:
    preferred_term: gout
    term:
      id: HP:0001997
      label: Gout
  evidence:
  - reference: PMID:8475950
    reference_title: "Lead nephropathy, gout, and hypertension."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Renal function and biopsy studies showed that lead nephropathy is a chronic tubulointerstitial renal disease with modest proteinuria which frequently presents with hyperuricemia, gout and hypertension."
    explanation: Supports gout as a recognized metabolic complication of chronic lead nephropathy.
- category: Oral
  name: Gingival lead line
  frequency: OCCASIONAL
  description: >-
    Burton line or lead-line gingival discoloration is a classic oral finding
    in chronic lead poisoning.
  phenotype_term:
    preferred_term: gingival lead line
    term:
      id: HP:0000168
      label: Abnormality of the gingiva
  evidence:
  - reference: PMID:6943483
    reference_title: "Gingival pigmentation as the sole presenting sign of chronic lead poisoning in a mentally retarded adult."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "A diagnosis of chronic lead poisoning in a mentally retarded adult with pica was initially proposed because of the presence of a \"lead line\" on the patient's gingiva."
    explanation: Direct human clinical evidence supports Burton-line gingival changes as a classic physical finding in chronic lead poisoning.
histopathology:
- name: Basophilic stippling of erythrocytes
  description: >-
    Peripheral blood smear may show basophilic stippling of red blood cells
    due to aggregated ribosomes in lead intoxication. This is a classic but
    nonspecific microscopic finding.
  context: Peripheral blood smear in lead intoxication
  diagnostic: false
  evidence:
  - reference: PMID:6202140
    reference_title: "Basophilic stippling of red blood cells: a nonspecific finding of multiple etiology."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Basophilic stippling of red blood cells (BSC) has been noted in lead intoxication since 1899 and has been considered a classic laboratory sign of lead poisoning since that time."
    explanation: Supports basophilic stippling as the classic hematologic microscopic finding in lead poisoning.
  - reference: PMID:1030853
    reference_title: "Chronic industrial exposure to lead in 63 subjects. I. Clinical and erythrokinetic findings."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Other associated findings were: higher reticulocyte counts and more basophilic stippling of the RBCs, more sideroblasts and greater erythroid hyperplasia of the bone marrow"
    explanation: Supports basophilic stippling as an observed microscopic feature in chronically lead-exposed patients.
  notes: Basophilic stippling is supportive but not specific for lead poisoning.
- name: Proximal tubular nuclear inclusion bodies
  description: >-
    Early lead nephropathy is characterized by proximal tubular nuclear
    inclusion bodies formed by lead-protein complexes, alongside chronic
    tubulointerstitial disease and fibrosis.
  context: Renal biopsy in lead nephropathy
  diagnostic: true
  evidence:
  - reference: PMID:2650022
    reference_title: "Mechanisms of lead and cadmium nephrotoxicity."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Exposure to lead results in accumulation in proximal renal tubular lining cells in the form of morphologically discernible inclusion bodies which are lead-protein complexes."
    explanation: Supports proximal tubular nuclear inclusion bodies as a characteristic microscopic renal lesion in lead nephrotoxicity.
  - reference: PMID:19106433
    reference_title: "Nephrotoxicity of cadmium & lead."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "both entities are characterized by tubulointerstitial disease and fibrosis, but only early lead nephropathy is characterized by the presence of proximal tubule nuclear inclusion bodies, due to the combination of lead with a lead binding-protein."
    explanation: Distinguishes lead nephropathy histopathology from cadmium nephropathy by the presence of proximal tubular nuclear inclusion bodies.
biochemical:
- name: Blood Lead Level
  presence: INCREASED
  notes: >-
    Venous whole-blood lead measurement is the primary laboratory test for
    confirming exposure and guiding intervention thresholds.
  evidence:
  - reference: PMID:37478813
    reference_title: "Trends in Blood Lead Levels Quantified by ICP-MS: A Reference Laboratory Retrospective Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Consequently, in 2021, the Centers for Disease Control and Prevention (CDC) reduced its blood lead reference value from 5 µg/dL to 3.5 µg/dL in pediatric patients, 1 to 5 years old."
    explanation: Supports blood lead concentration as the central biomarker for diagnosis and public-health intervention.
- name: Zinc Protoporphyrin
  presence: INCREASED
  notes: >-
    Zinc protoporphyrin is an adjunct biomarker of disrupted heme synthesis and
    has been used for biologic monitoring of lead exposure.
  evidence:
  - reference: PMID:6202140
    reference_title: "Basophilic stippling of red blood cells: a nonspecific finding of multiple etiology."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Furthermore, BSC has been replaced by blood lead (since the 1940s) and zinc protoporphyrin (since the 1970s) levels for biologic monitoring of lead-exposed workers."
    explanation: Supports zinc protoporphyrin as a laboratory biomarker used in monitoring lead exposure.
environmental:
- name: Lead-based paint
  exposure_term:
    preferred_term: exposure to lead
    term:
      id: ECTO:9000945
      label: exposure to lead
  environment_context:
    preferred_term: lead paint
    term:
      id: ENVO:02000124
      label: lead paint
  description: >-
    Deteriorating lead-based paint remains a major pediatric exposure source,
    especially where older housing stock is present.
  evidence:
  - reference: PMID:28889260
    reference_title: "Developmental Neurotoxicity of Lead."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Environmental exposures to lead, predominantly from contaminated water or lead paint chips, account for the majority of exposures to children."
    explanation: Supports lead paint as a major pediatric exposure source.
- name: Household dust
  exposure_term:
    preferred_term: exposure to lead
    term:
      id: ECTO:9000945
      label: exposure to lead
  environment_context:
    preferred_term: household dust
    term:
      id: ENVO:00002008
      label: dust
  description: >-
    Contaminated household dust is an important secondary exposure source for
    children, especially in homes with legacy lead contamination.
  evidence:
  - reference: PMID:32651990
    reference_title: "Contribution of house dust contamination towards lead exposure among children in Karachi, Pakistan."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Thus, house dust is an important source of lead exposure in Pakistani children."
    explanation: Direct human exposure data support contaminated household dust as a meaningful pediatric lead source.
- name: Contaminated drinking water
  exposure_term:
    preferred_term: exposure to lead in water via ingestion
    term:
      id: ECTO:0080003
      label: exposure to lead in water via ingestion
  environment_context:
    preferred_term: drinking water
    term:
      id: ENVO:00003064
      label: drinking water
  description: >-
    Lead in drinking water from aging infrastructure remains an important source
    of environmental exposure.
  evidence:
  - reference: PMID:28889260
    reference_title: "Developmental Neurotoxicity of Lead."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Environmental exposures to lead, predominantly from contaminated water or lead paint chips, account for the majority of exposures to children."
    explanation: Supports contaminated water as a major exposure source.
- name: Contaminated spices and turmeric
  exposure_term:
    preferred_term: exposure to lead
    term:
      id: ECTO:9000945
      label: exposure to lead
  description: >-
    Lead-contaminated food products, especially locally sourced spices and
    turmeric, can materially increase blood lead levels in children.
  evidence:
  - reference: PMID:36962532
    reference_title: "Prevalence of elevated blood lead levels and risk factors among children living in Patna, Bihar, India 2020."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Children in Patna, Bihar, India are exposed to multiple sources of lead, with lead levels in house dust and loose, locally sourced spices the most likely to increase blood lead levels."
    explanation: Direct pediatric exposure data support contaminated spices as a foodborne source of lead exposure.
- name: Lead-soldered food and drink cans
  exposure_term:
    preferred_term: exposure to lead
    term:
      id: ECTO:9000945
      label: exposure to lead
  description: >-
    Historically, lead-soldered food and drink cans were an important dietary
    exposure source before population-level control efforts reduced this route.
  evidence:
  - reference: PMID:9799191
    reference_title: "Exposure of the U.S. population to lead, 1991-1994."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Public health efforts have been successful in removing lead from population-wide sources such as gasoline and lead-soldered food and drink cans, but new efforts must address the difficult problem of leaded paint, especially in older houses, as well as lead in dust and soil."
    explanation: Supports lead-soldered food and drink cans as a recognized historical food-related source of lead exposure.
- name: Battery manufacture
  exposure_term:
    preferred_term: exposure to lead
    term:
      id: ECTO:9000945
      label: exposure to lead
  description: >-
    Occupational and para-occupational lead exposure occurs in battery
    manufacture and related industrial handling.
  evidence:
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Contemporary contamination primarily stems from mining activities, battery manufacturing, electronic waste recycling, and deteriorating infrastructure."
    explanation: Supports battery manufacturing as a contemporary industrial exposure source for lead poisoning.
- name: Mining
  exposure_term:
    preferred_term: exposure to lead
    term:
      id: ECTO:9000945
      label: exposure to lead
  description: >-
    Mining activities remain an important occupational and community source of
    lead contamination and exposure.
  evidence:
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Contemporary contamination primarily stems from mining activities, battery manufacturing, electronic waste recycling, and deteriorating infrastructure."
    explanation: Supports mining activities as a contemporary source of lead exposure.
- name: E-waste recycling
  exposure_term:
    preferred_term: exposure to lead
    term:
      id: ECTO:9000945
      label: exposure to lead
  environment_context:
    preferred_term: electronic waste material
    term:
      id: ENVO:00002264
      label: waste material
  description: >-
    Electronic waste recycling is an important contemporary source of lead
    exposure through handling and processing of contaminated materials.
  evidence:
  - reference: PMID:40981357
    reference_title: "The Mechanisms of Lead Toxicity in Living Organisms."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Contemporary contamination primarily stems from mining activities, battery manufacturing, electronic waste recycling, and deteriorating infrastructure."
    explanation: Supports electronic waste recycling as a contemporary source of lead exposure.
- name: Lead-adulterated oral opium
  exposure_term:
    preferred_term: exposure to lead
    term:
      id: ECTO:9000945
      label: exposure to lead
  description: >-
    Illicit oral opium contaminated with lead can cause major community
    outbreaks of lead poisoning, especially with chronic use.
  evidence:
  - reference: PMID:29531415
    reference_title: "Lead poisoning outbreak among opium users in the Islamic Republic of Iran, 2016-2017."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lead-contaminated opium and heroin that has transited through the Iranian markets is a global risk and highlights a need for better monitoring of illegal drug supplies."
    explanation: Supports adulterated oral opium as a documented non-occupational source of lead poisoning.
  - reference: PMID:29531415
    reference_title: "Lead poisoning outbreak among opium users in the Islamic Republic of Iran, 2016-2017."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Analysis of an illegal opium sample showed 3.55 mg lead in 1 g opium."
    explanation: Directly demonstrates lead contamination of illicit opium as the proximate exposure source in a large outbreak.
- name: Lead-adulterated heroin
  exposure_term:
    preferred_term: exposure to lead
    term:
      id: ECTO:9000945
      label: exposure to lead
  description: >-
    Illicit heroin contaminated with lead is a documented non-occupational
    exposure source that can contribute to community lead poisoning.
  evidence:
  - reference: PMID:29531415
    reference_title: "Lead poisoning outbreak among opium users in the Islamic Republic of Iran, 2016-2017."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Lead-contaminated opium and heroin that has transited through the Iranian markets is a global risk and highlights a need for better monitoring of illegal drug supplies."
    explanation: Supports adulterated heroin as a documented non-occupational source of lead poisoning.
treatments:
- name: Exposure cessation and source control
  description: >-
    The first intervention is removal from the lead source and prevention of
    ongoing exposure.
  treatment_term:
    preferred_term: supportive care
    term:
      id: MAXO:0000950
      label: supportive care
  target_mechanisms:
  - target: Lead absorption
    treatment_effect: INHIBITS
    description: Source control prevents continued lead entry and lowers ongoing systemic burden.
    evidence:
    - reference: PMID:8475950
      reference_title: "Lead nephropathy, gout, and hypertension."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "While chelation therapy is safe and helpful in reversing early lead nephropathy, the best treatment is prevention."
      explanation: Supports exposure prevention as the primary intervention that blocks continued toxic lead burden.
  evidence:
  - reference: PMID:8475950
    reference_title: "Lead nephropathy, gout, and hypertension."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "While chelation therapy is safe and helpful in reversing early lead nephropathy, the best treatment is prevention."
    explanation: Supports exposure prevention and source removal as the foundational management strategy.
- name: Succimer chelation
  description: >-
    Oral succimer is used as a lead chelator, particularly in children with
    elevated blood lead concentrations.
  treatment_term:
    preferred_term: chelator agent therapy
    term:
      id: MAXO:0001223
      label: chelator agent therapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: succimer
        term:
          id: CHEBI:63623
          label: succimer
  target_mechanisms:
  - target: Systemic lead distribution
    treatment_effect: INHIBITS
    description: Succimer lowers circulating and soft-tissue lead burden by forming excretable complexes with lead.
    evidence:
    - reference: PMID:1663439
      reference_title: "Succimer, an oral lead chelator."
      supports: SUPPORT
      evidence_source: OTHER
      snippet: "Succimer is an orally active, heavy-metal chelating agent that forms stable, water-soluble complexes with lead; it also chelates other toxic heavy metals, such as arsenic and mercury."
      explanation: Directly supports chelation of systemic lead as the proximate treatment mechanism of succimer.
  evidence:
  - reference: PMID:1663439
    reference_title: "Succimer, an oral lead chelator."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "It is a designated orphan drug that is indicated for the treatment of lead poisoning, specifically in children with blood lead concentrations higher than 45 micrograms/dL."
    explanation: Directly supports succimer as an indicated chelation therapy for pediatric lead poisoning.
- name: Calcium disodium edetate chelation
  description: >-
    Calcium disodium EDTA chelation is used in selected patients with
    significant body lead burden, particularly when nephropathy is present.
  treatment_term:
    preferred_term: chelator agent therapy
    term:
      id: MAXO:0001223
      label: chelator agent therapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: edetic acid
        term:
          id: NCIT:C61742
          label: Edetic Acid
  evidence:
  - reference: PMID:8475950
    reference_title: "Lead nephropathy, gout, and hypertension."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "While chelation therapy is safe and helpful in reversing early lead nephropathy, the best treatment is prevention."
    explanation: Supports chelation therapy, including EDTA-based approaches discussed in lead nephropathy, as helpful in early disease.
- name: Dimercaprol chelation
  description: >-
    Dimercaprol is used with calcium disodium EDTA in more severely intoxicated
    patients, including severe acute lead poisoning and lead encephalopathy.
  treatment_term:
    preferred_term: chelator agent therapy
    term:
      id: MAXO:0001223
      label: chelator agent therapy
    qualifiers:
    - predicate:
        preferred_term: therapeutic agent
        term:
          id: NCIT:C2259
          label: Therapeutic Agent
      value:
        preferred_term: dimercaprol
        term:
          id: CHEBI:29045
          label: dimercaprol
  evidence:
  - reference: PMID:3540517
    reference_title: "Lead intoxication."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Treatment of patients with positive chelation tests involves symptomatic treatment and a course of chelation therapy utilising calcium disodium edetate in doses similar to those used for testing, and in the more severely intoxicated patient, the addition of dimercaprol in doses of 75 mg/m2 every 4 hours to a total of 300 mg/m2/day."
    explanation: Supports dimercaprol as an established adjunct chelator for severe lead intoxication.
diagnosis:
- name: Blood lead level measurement
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: MAXO:0000003
      label: diagnostic procedure
    qualifiers:
    - predicate:
        preferred_term: diagnostic procedure
        term:
          id: NCIT:C18020
          label: Diagnostic Procedure
      value:
        preferred_term: laboratory procedure
        term:
          id: NCIT:C25294
          label: Laboratory Procedure
  description: >-
    Venous whole-blood lead measurement is the primary laboratory method for
    confirming lead exposure and determining intervention thresholds.
  markers: Blood lead concentration in venous whole blood
  results: >-
    Elevated blood lead concentration; CDC pediatric blood lead reference value
    cited here is 3.5 microgram/dL.
  evidence:
  - reference: PMID:37478813
    reference_title: "Trends in Blood Lead Levels Quantified by ICP-MS: A Reference Laboratory Retrospective Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Consequently, in 2021, the Centers for Disease Control and Prevention (CDC) reduced its blood lead reference value from 5 µg/dL to 3.5 µg/dL in pediatric patients, 1 to 5 years old."
    explanation: Supports blood lead concentration as the core diagnostic and screening measure.
- name: Zinc protoporphyrin testing
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: MAXO:0000003
      label: diagnostic procedure
    qualifiers:
    - predicate:
        preferred_term: diagnostic procedure
        term:
          id: NCIT:C18020
          label: Diagnostic Procedure
      value:
        preferred_term: laboratory procedure
        term:
          id: NCIT:C25294
          label: Laboratory Procedure
  description: >-
    Zinc protoporphyrin measurement is an adjunct laboratory test reflecting
    disturbed heme synthesis in lead exposure.
  markers: Zinc protoporphyrin
  results: Elevated zinc protoporphyrin supports disrupted heme synthesis in lead exposure.
  evidence:
  - reference: PMID:6202140
    reference_title: "Basophilic stippling of red blood cells: a nonspecific finding of multiple etiology."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Furthermore, BSC has been replaced by blood lead (since the 1940s) and zinc protoporphyrin (since the 1970s) levels for biologic monitoring of lead-exposed workers."
    explanation: Supports zinc protoporphyrin as an adjunct biomarker in evaluation of lead exposure.
- name: EDTA lead mobilization testing
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: MAXO:0000003
      label: diagnostic procedure
    qualifiers:
    - predicate:
        preferred_term: diagnostic procedure
        term:
          id: NCIT:C18020
          label: Diagnostic Procedure
      value:
        preferred_term: laboratory procedure
        term:
          id: NCIT:C25294
          label: Laboratory Procedure
  description: >-
    In suspected chronic lead nephropathy, EDTA lead mobilization testing can
    help estimate retained body lead burden when blood lead concentration alone
    is insufficient.
  markers: Mobilizable body lead burden after EDTA challenge
  results: Detects increased mobilizable body lead burden in suspected chronic lead nephropathy.
  evidence:
  - reference: PMID:8475950
    reference_title: "Lead nephropathy, gout, and hypertension."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Only evaluation of body lead stores by either the EDTA lead mobilization test or by x-ray fluorescence is helpful in diagnosing lead nephropathy."
    explanation: Supports EDTA lead mobilization testing as a diagnostic approach for retained body lead burden in chronic lead nephropathy.
- name: X-ray fluorescence body burden assessment
  diagnosis_term:
    preferred_term: diagnostic procedure
    term:
      id: MAXO:0000003
      label: diagnostic procedure
    qualifiers:
    - predicate:
        preferred_term: diagnostic procedure
        term:
          id: NCIT:C18020
          label: Diagnostic Procedure
      value:
        preferred_term: X-Ray imaging
        term:
          id: NCIT:C38101
          label: X-Ray Imaging
  description: >-
    X-ray fluorescence can noninvasively assess retained body lead burden in
    patients with suspected chronic lead nephropathy.
  markers: Bone or body lead burden by X-ray fluorescence
  results: Detects increased retained body lead stores in suspected chronic lead nephropathy.
  evidence:
  - reference: PMID:8475950
    reference_title: "Lead nephropathy, gout, and hypertension."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Only evaluation of body lead stores by either the EDTA lead mobilization test or by x-ray fluorescence is helpful in diagnosing lead nephropathy."
    explanation: Supports X-ray fluorescence as a diagnostic method for retained body lead burden in chronic lead nephropathy.
epidemiology:
- name: Pediatric vulnerability
  description: >-
    Children remain the most vulnerable population for lead poisoning because
    common environmental sources intersect with sensitive neurodevelopmental
    windows.
  evidence:
  - reference: PMID:28889260
    reference_title: "Developmental Neurotoxicity of Lead."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Lead exposure is a major concern for the developing nervous system."
    explanation: Supports the special epidemiologic importance of pediatric lead exposure.
- name: Lower pediatric blood lead intervention threshold
  description: >-
    Public-health thresholds for pediatric blood lead intervention have been
    lowered as evidence has accumulated that there is no safe lead exposure
    level.
  evidence:
  - reference: PMID:37478813
    reference_title: "Trends in Blood Lead Levels Quantified by ICP-MS: A Reference Laboratory Retrospective Study."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Consequently, in 2021, the Centers for Disease Control and Prevention (CDC) reduced its blood lead reference value from 5 µg/dL to 3.5 µg/dL in pediatric patients, 1 to 5 years old."
    explanation: Supports contemporary epidemiologic concern about lower-level pediatric lead exposure.
prevalence:
- population: United States population aged 1 year and older, 1991-1994
  percentage: 2.2
  notes: >-
    Historical NHANES III estimate using the then-current threshold of blood
    lead >=10 microgram/dL. This reflects elevated blood lead prevalence rather
    than a modern case definition of clinical lead poisoning.
  evidence:
  - reference: PMID:9799191
    reference_title: "Exposure of the U.S. population to lead, 1991-1994."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The overall mean blood lead level for the U.S. population aged 1 year and older was 2.3 microgram/dl, with 2.2% of the population having levels >=10 microgram/dl, the level of health concern for children."
    explanation: Provides a population-based historical prevalence estimate for elevated blood lead levels in the United States.
- population: Children living in Patna, Bihar, India, 2020
  percentage: 87
  notes: >-
    Local pediatric prevalence estimate for blood lead levels >=5 microgram/dL
    in a high-exposure setting. This is not a general-population prevalence
    estimate for lead poisoning.
  evidence:
  - reference: PMID:36962532
    reference_title: "Prevalence of elevated blood lead levels and risk factors among children living in Patna, Bihar, India 2020."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "About 87% children, 56 Proximal and 62 Distal had BLLs ≥5 μg/dl."
    explanation: Supports a contemporary high-burden pediatric prevalence estimate from a defined environmental exposure setting.
differential_diagnoses:
- name: Cadmium Poisoning
  description: >-
    Cadmium poisoning overlaps with lead toxicity through chronic occupational
    exposure and proximal tubular nephrotoxicity, but the renal phenotype and
    associated laboratory findings differ.
  disease_term:
    preferred_term: cadmium poisoning
    term:
      id: MONDO:0043523
      label: cadmium poisoning
  distinguishing_features:
  - Cadmium causes Fanconi syndrome with low-molecular-weight proteinuria and beta2-microglobulinuria
  - Lead nephropathy instead is associated with hyperuricemia, gout, and hypertension
  - Proximal tubule nuclear inclusion bodies are characteristic of early lead nephropathy
  evidence:
  - reference: PMID:19106433
    reference_title: "Nephrotoxicity of cadmium & lead."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Cadmium in sufficient cumulative dosage leads to the production of the Fanconi syndrome, a generalized proximal tubular reabsorptive defect thought to be related to inhibition of both ATP production and Na-K-ATPase activity. On the other hand, lead accumulation in the proximal tubule leads to hyperuricaemia and gout, presumably by inhibiting uric acid secretion, and diminished glomerular filteration rate (GFR)."
    explanation: Directly contrasts cadmium and lead nephrotoxicity, supporting cadmium poisoning as a major differential diagnosis.
  - reference: PMID:19106433
    reference_title: "Nephrotoxicity of cadmium & lead."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "Beta2-microglobulinuria is not found in lead nephropathy."
    explanation: Supports beta2-microglobulinuria as a distinguishing feature favoring cadmium over lead toxicity.
- name: Arsenic Poisoning
  description: >-
    Arsenic poisoning can overlap with lead poisoning through gastrointestinal
    symptoms and neuropathy, but chronic arsenic exposure more strongly
    features characteristic skin findings and carcinogenic sequelae.
  distinguishing_features:
  - Chronic arsenic exposure causes hyperpigmentation and palmoplantar keratoses
  - Arsenic exposure is strongly associated with skin, lung, and bladder cancer
  - Lead poisoning more characteristically shows basophilic stippling, lead-line gingival changes, and ALAD inhibition
  evidence:
  - reference: PMID:28005215
    reference_title: "ARSENIC: A Review on Exposure Pathways, Accumulation, Mobility and Transmission into the Human Food Chain."
    supports: SUPPORT
    evidence_source: OTHER
    snippet: "It is proven fact that uptake of inorganic As for a long period can lead to chronic As poisoning and a variety of adverse health effects such as skin, lung and bladder cancer, in addition to cardiovascular diseases, diabetes and gastrointestinal symptoms."
    explanation: Supports the chronic dermatologic and carcinogenic profile that distinguishes arsenic poisoning from lead toxicity.
  - reference: PMID:17405745
    reference_title: "Anaemia and abdominal pain due to occupational lead poisoning."
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We describe a 47-year-old patient with chronic anaemia with basophilic stippling of erythrocytes, recurrent abdominal colics, discoloration of gums, sensitive polyneuropathy to the four limbs, hyperuricaemia, hepatosteatosis with raised transaminases, and a long ignored history of lead exposure in a battery recycling plant."
    explanation: Supports the lead-specific constellation of basophilic stippling, abdominal colic, and occupational exposure history.
animal_models:
- species: Mus musculus
  background: C57BL/6
  description: >-
    Adult female C57BL/6 mice exposed to lead in drinking water for 4 months
    develop altered bone mineral density, increased bone turnover, and weaker
    cortical bone, modeling the skeletal reservoir and bone toxicity of chronic
    lead exposure.
  associated_phenotypes:
  - Increased bone turnover
  - Reduced bone strength
  - Altered bone mineral density
  evidence:
  - reference: PMID:20643234
    reference_title: "The effect of lead on bone mineral properties from female adult C57/BL6 mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "These data show that lead increases bone turnover resulting in weaker cortical bone in adult female mice and suggest that lead may exacerbate bone loss and osteoporosis in the elderly."
    explanation: Establishes a chronic murine skeletal model of lead deposition and bone toxicity.
- species: Mus musculus
  background: BALB/cAnNTac
  description: >-
    Developmental lead exposure from gestation through weaning in BALB/cAnNTac
    mice produces adult behavioral abnormalities and whole-brain inflammatory
    gene-expression changes, modeling developmental neurotoxicity.
  associated_phenotypes:
  - Impaired spatial memory
  - Altered exploratory behavior
  - Neuroinflammatory gene-expression changes
  evidence:
  - reference: PMID:22609695
    reference_title: "Developmental lead effects on behavior and brain gene expression in male and female BALB/cAnNTac mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Pups were exposed to Pb from gestational-day (gd) 8 to postnatal-day (pnd) 21 and later evaluated in exploratory behavior, rotarod, Morris water maze, and resident-intruder assays as adults."
    explanation: Establishes a developmental mouse exposure paradigm for long-term behavioral lead neurotoxicity.
  - reference: PMID:22609695
    reference_title: "Developmental lead effects on behavior and brain gene expression in male and female BALB/cAnNTac mice."
    supports: SUPPORT
    evidence_source: MODEL_ORGANISM
    snippet: "Pb-exposure caused significant alterations in exploratory behavior and water maze performance during the probe trial, but rotarod performance was not affected."
    explanation: Supports measurable adult cognitive and behavioral phenotypes in the developmental lead mouse model.
datasets:
- accession: geo:GSE37567
  title: Methodoligies for identifying lead toxicity
  description: >-
    Human PBMC transcriptomic dataset used to quantify the impact of lead on
    cytokine production and gene expression in peripheral blood mononuclear
    cells.
  organism:
    preferred_term: human
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  data_type: MICROARRAY
  sample_types:
  - preferred_term: peripheral blood mononuclear cells
    cell_type_term:
      preferred_term: peripheral blood mononuclear cell
      term:
        id: CL:0000842
        label: mononuclear leukocyte
    tissue_term:
      preferred_term: blood
      term:
        id: UBERON:0000178
        label: blood
  sample_count: 102
  conditions:
  - lead-associated PBMC cytokine and gene-expression profiling
  evidence:
  - reference: GEO:GSE37567
    supports: SUPPORT
    evidence_source: IN_VITRO
    snippet: "Quantifying impact of lead on cytokine production and gene expression in PBMCs"
    explanation: Supports this dataset as a lead-relevant PBMC transcriptomic resource.
- accession: geo:GSE60598
  title: Early life Lead exposure causes distinct gender specific changes in the DNA methylation profile of DNA extracted from dried blood spots
  description: >-
    Human methylation dataset from dried blood spots in a Detroit pediatric
    cohort, profiling sex-specific epigenomic effects of early-life lead
    exposure.
  organism:
    preferred_term: human
    term:
      id: NCBITaxon:9606
      label: Homo sapiens
  data_type: METHYLATION
  sample_types:
  - preferred_term: dried blood spots
    term:
      id: UBERON:0000178
      label: blood
    tissue_term:
      preferred_term: blood
      term:
        id: UBERON:0000178
        label: blood
  sample_count: 43
  conditions:
  - early-life lead exposure
  - pediatric blood-spot methylation profiling
  exposures:
  - preferred_term: lead exposure
    term:
      id: ECTO:9000945
      label: exposure to lead
  evidence:
  - reference: GEO:GSE60598
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Study of influence of gender and Lead(Pb) exposure on DNA methylation for whole blood measured in dried blood spots for a Detroit cohort of child between the age of 3 months to 5years"
    explanation: Supports this dataset as a pediatric human epigenomic resource for lead exposure effects.
clinical_trials:
- name: NCT00342849
  phase: PHASE_III
  status: COMPLETED
  description: >-
    Treatment of Lead-Exposed Children (TLC) was a randomized, double-blind,
    placebo-controlled multicenter trial comparing succimer chelation with
    placebo in lead-exposed children, with follow-up focused on IQ,
    neuropsychological function, behavior, growth, and blood pressure.
  target_phenotypes:
  - preferred_term: cognitive impairment
    term:
      id: HP:0100543
      label: Cognitive impairment
  evidence:
  - reference: clinicaltrials:NCT00342849
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The Treatment of Lead-Exposed Children (TLC) clinical trial compared the effect of lead chelation with succimer to placebo therapy."
    explanation: Supports a definitive randomized therapeutic trial of succimer in lead-exposed children.
  - reference: clinicaltrials:NCT00342849
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "The study was designed to test outcomes in IQ, neuropsychological function, behavior, physical growth and blood pressure three years after initiation of treatment."
    explanation: Supports neurocognitive and physiologic outcome assessment relevant to lead toxicity.
- name: NCT01573013
  phase: NOT_APPLICABLE
  status: COMPLETED
  description: >-
    Interventional study in Morocco evaluating whether iron fortification,
    with or without NaFeEDTA, can reduce blood lead levels and improve growth,
    motor performance, cognition, and iron status in lead-exposed children.
  target_phenotypes:
  - preferred_term: anemia
    term:
      id: HP:0001903
      label: Anemia
  - preferred_term: cognitive impairment
    term:
      id: HP:0100543
      label: Cognitive impairment
  evidence:
  - reference: clinicaltrials:NCT01573013
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "In a follow-on intervention study, the effect of iron fortification with and without NaEDTA on blood lead levels in lead-exposed children will be evaluated; and the relative impact of these two strategies on child growth, motor and cognitive test performance will be compared."
    explanation: Supports an interventional trial targeting both lead burden and functional outcomes in exposed children.
  - reference: clinicaltrials:NCT01573013
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "This study will investigate the potential use of iron fortification to not only combat anemia but also reduce body lead burden in lead-exposed populations; it specifically investigates whether iron fortification with NaFeEDTA could have additional beneficial effects to iron alone."
    explanation: Supports anemia-focused nutritional intervention as part of lead poisoning management research.
- name: NCT05507021
  phase: NOT_APPLICABLE
  status: COMPLETED
  description: >-
    Randomized, placebo-controlled pilot trial evaluating Lactobacillus
    plantarum DSM 33464 as a biologic intervention to reduce blood lead levels
    in young women of child-bearing age.
  target_phenotypes:
  - preferred_term: anemia
    term:
      id: HP:0001903
      label: Anemia
  - preferred_term: cognitive impairment
    term:
      id: HP:0100543
      label: Cognitive impairment
  evidence:
  - reference: clinicaltrials:NCT05507021
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "We hypothesize that Lactobacillus Plantarum DSM 33464 reduce lead levels."
    explanation: Supports a completed pilot interventional study aimed at lowering blood lead burden.
  - reference: clinicaltrials:NCT05507021
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "From that pool of subjects, 40 healthy women aged 18 to 40 years will participate in this randomized, placebo controlled pilot clinical trial."
    explanation: Supports the interventional randomized design of this lead-reduction trial.