Congenital Hypothyroidism

Complex MONDO:0018612 Pathograph 8 hypothyroidism

Congenital hypothyroidism is thyroid hormone deficiency present at birth and is one of the most common preventable causes of intellectual disability worldwide. The primary form, caused by thyroid dysgenesis or dyshormonogenesis, accounts for the vast majority of cases with an incidence of 1 in 2000 to 1 in 3000. Universal newborn screening enables early detection and treatment with levothyroxine, which prevents irreversible neurodevelopmental damage when initiated within the first two weeks of life.

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2
Inheritance
5
Pathophys.
13
Phenotypes
8
Pathograph
10
Genes
3
Treatments
4
Subtypes
1
Deep Research
👪

Inheritance

2
Autosomal recessive inheritance HP:0000007
Dyshormonogenesis subtypes (TPO, TG, DUOX2, DUOXA2, SLC5A5, SLC26A4 mutations) follow autosomal recessive inheritance with 25% recurrence risk.
Autosomal recessive inheritance
Show evidence (2 references)
PMID:29650690 SUPPORT Human Clinical
"Autosomal recessive inheritance of CH caused by mutations in DUOX2, DUOXA2, TG and TPO was confirmed by analysis of 22 family pedigrees."
Family pedigree analysis confirms autosomal recessive inheritance for dyshormonogenesis genes.
PMID:33272083 SUPPORT Human Clinical
"Counseling should include explaining inheritance and the risk of recurrence of the patient's primary or central form of CH, based on the CH subtype, the family history, and, if known, the (genetic) cause"
Guidelines recommend counseling on inheritance including recurrence risk for autosomal recessive forms.
Sporadic occurrence
Thyroid dysgenesis, the most common cause of primary CH, is typically sporadic with unclear inheritance. Monogenic, polygenic, and multifactorial inheritance have all been proposed.
Show evidence (1 reference)
PMID:29650690 SUPPORT Human Clinical
"eight mutations in four genes (FOXE1, NKX2-1, PAX8 and HHEX) that lead to thyroid dysgenesis were identified in eight probands. These mutations were heterozygous in all cases and hypothyroidism was not observed in parents of these probands."
Heterozygous mutations in thyroid dysgenesis genes with unaffected parents suggest complex or sporadic rather than simple dominant inheritance.
◆

Subtypes

4
Permanent Primary Congenital Hypothyroidism MONDO:0016408
Permanent thyroid hormone deficiency due to thyroid gland dysgenesis (agenesis, ectopy, hypoplasia) or dyshormonogenesis, requiring lifelong levothyroxine replacement. Thyroid dysgenesis accounts for 65-85% of primary CH cases.
Transient Congenital Hypothyroidism MONDO:0015792
Temporary thyroid hormone deficiency at birth that resolves spontaneously, commonly due to maternal antithyroid antibodies, iodine excess or deficiency, or prematurity.
Central Congenital Hypothyroidism MONDO:0016410
Congenital thyroid hormone deficiency caused by insufficient hypothalamic or pituitary stimulation of the thyroid gland, with low free T4 and non-elevated TSH. Incidence approximately 1 in 16,000.
Familial Thyroid Dyshormonogenesis MONDO:0010132
Autosomal recessive defects in thyroid hormone synthesis enzymes and transporters (TPO, TG, DUOX2, SLC5A5, SLC26A4) causing goitrous congenital hypothyroidism.
⚙

Pathophysiology

5
Thyroid Gland Dysgenesis
The most common cause of permanent primary congenital hypothyroidism is abnormal thyroid gland development, including thyroid agenesis, ectopy, or hypoplasia, resulting in insufficient thyroid hormone production from birth. Thyroid dysgenesis accounts for 65-85% of primary CH cases.
thyroid follicular cell link
Thyroid gland development link ⚠ ABNORMAL Thyroid hormone generation link ↓ DECREASED
thyroid gland link
Downstream
Neurodevelopmental Impairment from Thyroid Hormone Deficiency Insufficient thyroid hormone production from dysgenetic thyroid tissue leads to thyroid hormone deficiency during critical periods of brain development.
Show evidence (2 references)
PMID:41303336 SUPPORT Human Clinical
"The primary form of CH is attributable to thyroid dysgenesis (agenesis, hypoplasia, or ectopy) in 65-85% of cases, with the remaining cases being attributed to dyshormogenesis."
Directly states the proportion of primary CH attributable to thyroid dysgenesis and its subtypes.
PMID:25729683 SUPPORT Human Clinical
"In the majority of patients, CH is caused by an abnormal development of the thyroid gland (thyroid dysgenesis) that is a sporadic disorder and accounts for 85% of cases and the remaining 15% of cases are caused by dyshormonogenesis."
Confirms thyroid dysgenesis as the predominant cause of CH and provides the 85%/15% proportion.
Defective Thyroid Hormone Biosynthesis
Inborn errors of thyroid hormone synthesis due to mutations in genes encoding enzymes and transporters required for iodide organification and thyroid hormone biosynthesis (TPO, TG, DUOX2, SLC5A5, SLC26A4), typically resulting in goitrous hypothyroidism.
thyroid follicular cell link
Thyroid hormone generation link ↓ DECREASED
thyroid gland link
Downstream
Neurodevelopmental Impairment from Thyroid Hormone Deficiency Impaired thyroid hormone synthesis leads to the same downstream thyroid hormone deficiency as dysgenesis, though the thyroid gland is present and often goitrous.
Show evidence (2 references)
PMID:29650690 SUPPORT Human Clinical
"Our results showed that 57 patients (51.82%) carried biallelic mutations (containing compound heterozygous mutations and homozygous mutations) in six genes (DUOX2, DUOXA2, DUOXA1, TG, TPO and TSHR) involved in thyroid hormone synthesis."
Demonstrates that dyshormonogenesis genes are the most common genetic cause identified in a comprehensive screening study.
PMID:37390946 SUPPORT Human Clinical
"DUOX2 gene had the highest variant rate, followed by TG, TPO and TSHR gene."
Confirms the relative frequency of dyshormonogenesis gene variants in a newborn screening cohort.
Impaired Hypothalamic-Pituitary TSH Drive
Deficient hypothalamic TRH signaling or pituitary thyrotroph dysfunction leads to inadequate TSH secretion, producing low free T4 with inappropriately low or normal TSH.
thyrotroph link
Thyroid-stimulating hormone secretion link ↓ DECREASED
hypothalamus-pituitary axis link
Downstream
Neurodevelopmental Impairment from Thyroid Hormone Deficiency Inadequate TSH drive results in insufficient thyroid hormone production, causing the same downstream neurodevelopmental risk.
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"If the serum fT4 is low, and TSH is low, normal or slightly elevated, the diagnosis central CH should be considered"
The consensus guidelines describe the biochemical pattern of central CH reflecting inadequate TSH drive.
Transient Thyroid Dysfunction
Transient congenital hypothyroidism results from reversible disruption of thyroid function, most commonly due to transplacental passage of maternal TSH receptor-blocking antibodies, exposure to excess iodine, or hypothalamic-pituitary-thyroid axis immaturity in premature infants.
Thyroid hormone generation link ↓ DECREASED
Downstream
Neurodevelopmental Impairment from Thyroid Hormone Deficiency Even transient thyroid hormone deficiency during critical neonatal brain development may cause neurodevelopmental harm if untreated.
Show evidence (2 references)
PMID:20537182 SUPPORT Human Clinical
"Transient CH most commonly occurs in preterm infants born in areas of endemic iodine deficiency."
Identifies prematurity and iodine deficiency as common causes of transient CH.
PMID:33272083 SUPPORT Human Clinical
"the prevalence of transient CH has steadily increased. In a number of studies, factors have been identified that increase the likelihood of transient disease, such as sex (more often in boys)"
Guidelines document the increasing prevalence and risk factors for transient CH.
Neurodevelopmental Impairment from Thyroid Hormone Deficiency
Thyroid hormone is indispensable for brain development during fetal life and the first 2-3 years. Deficiency during this critical period causes irreversible neurodevelopmental damage if untreated, historically known as cretinism.
neuron link
Brain development link ⚠ ABNORMAL
brain link
Show evidence (2 references)
PMID:29405999 SUPPORT Human Clinical
"Congenital hypothyroidism is common and can cause severe neurodevelopmental morbidity."
Directly states the neurodevelopmental consequence of congenital hypothyroidism.
PMID:25729683 SUPPORT Human Clinical
"delayed diagnosis leads to the most severe outcome of CH, mental retardation, emphasizing the importance of neonatal screening."
Confirms that delayed diagnosis leads to irreversible intellectual disability.
⬡

Pathograph

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

Phenotypes

13
Digestive 3
Prolonged Neonatal Jaundice Prolonged neonatal jaundice (HP:0006579)
Show evidence (2 references)
PMID:33272083 SUPPORT Human Clinical
"Isolated central CH due to biallelic TSHβ gene mutations is associated with severe hypothyroidism and characterized by the typical manifestations of CH (hypotonia, jaundice, umbilical hernia, macroglossia, etc.)."
The consensus guidelines list jaundice as a typical manifestation of congenital hypothyroidism.
PMID:33272083 SUPPORT Human Clinical
"we recommend endocrine testing in all neonates with a familial history of central CH, or signs or symptoms of congenital hypopituitarism, for example, micropenis with undescended testes, hypoglycemia, prolonged jaundice, or unexplained failure to thrive."
Guidelines specifically mention prolonged jaundice as a clinical sign warranting endocrine testing for congenital hypothyroidism.
Feeding Difficulties Feeding difficulties (HP:0011968)
Show evidence (1 reference)
PMID:20537182 SUPPORT Human Clinical
"Common symptoms include decreased activity and increased sleep, feeding difficulty, constipation, and prolonged jaundice."
Lists feeding difficulty as a common symptom of congenital hypothyroidism.
Constipation Constipation (HP:0002019)
Show evidence (1 reference)
PMID:20537182 SUPPORT Human Clinical
"Common symptoms include decreased activity and increased sleep, feeding difficulty, constipation, and prolonged jaundice."
Lists constipation as a common symptom of congenital hypothyroidism.
Endocrine 1
Goiter Goiter (HP:0000853)
Show evidence (2 references)
PMID:37390946 SUPPORT Human Clinical
"The "DUOX2 biallelic variants" group was associated with "Goiter""
Demonstrates the association of goiter with dyshormonogenesis gene variants, specifically DUOX2 biallelic mutations.
PMID:33272083 SUPPORT Human Clinical
"Children and adolescents with primary CH due to dyshomonogenesis may develop goiter and nodules; in these cases, serum TSH should be carefully targeted in the lower part of normal range and periodical ultrasound investigation is recommended to monitor thyroid volume"
Confirms goiter and nodule development in dyshormonogenesis and recommends monitoring.
Head and Neck 2
Macroglossia Macroglossia (HP:0000158)
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"Isolated central CH due to biallelic TSHβ gene mutations is associated with severe hypothyroidism and characterized by the typical manifestations of CH (hypotonia, jaundice, umbilical hernia, macroglossia, etc.)."
The consensus guidelines explicitly list macroglossia as a typical manifestation of congenital hypothyroidism.
Large Fontanelles Large fontanelles (HP:0000239)
Show evidence (1 reference)
PMID:20537182 SUPPORT Human Clinical
"On examination, common signs include myxedematous facies, large fontanels, macroglossia, a distended abdomen with umbilical hernia, and hypotonia."
Lists large fontanels as a common examination finding in congenital hypothyroidism.
Integument 1
Dry Skin Dry skin (HP:0000958)
Show evidence (1 reference)
PMID:20537182 SUPPORT Human Clinical
"On examination, common signs include myxedematous facies, large fontanels, macroglossia, a distended abdomen with umbilical hernia, and hypotonia."
Myxedematous facies in CH includes dry, thickened skin characteristic of hypothyroidism.
Musculoskeletal 1
Hypotonia Hypotonia (HP:0001252)
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"Isolated central CH due to biallelic TSHβ gene mutations is associated with severe hypothyroidism and characterized by the typical manifestations of CH (hypotonia, jaundice, umbilical hernia, macroglossia, etc.)."
The consensus guidelines explicitly list hypotonia as a typical manifestation of congenital hypothyroidism.
Nervous System 1
Intellectual Disability Intellectual disability (HP:0001249)
Show evidence (1 reference)
PMID:25729683 SUPPORT Human Clinical
"Congenital hypothyroidism (CH) is the one of the most common preventable cause of mental retardation."
Directly identifies intellectual disability as the most severe preventable outcome of untreated congenital hypothyroidism.
Growth 2
Short Stature Short stature (HP:0004322)
Show evidence (1 reference)
PMID:33272083 PARTIAL Human Clinical
"Adequately treated children with nonsyndromic CH have normal growth and puberty, and their fertility does not differ from individuals who do not have CH"
Indirectly supports short stature as a phenotype by stating that adequately treated CH results in normal growth, implying untreated CH leads to growth failure.
Failure to Thrive Failure to thrive (HP:0001508)
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"we recommend endocrine testing in all neonates with a familial history of central CH, or signs or symptoms of congenital hypopituitarism, for example, micropenis with undescended testes, hypoglycemia, prolonged jaundice, or unexplained failure to thrive."
The guidelines identify failure to thrive as a clinical sign prompting evaluation for congenital hypothyroidism.
Other 2
Congenital Hypothyroidism Congenital hypothyroidism (HP:0000851)
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"The incidence of CH partly depends on the screening strategy; based on data from a number of screening programs, the incidence of primary CH lies between 1 in 3000 and 1 in 2000; the highest reported incidence of central CH is ∼1 in 16,000"
Provides the incidence of primary and central congenital hypothyroidism from the consensus guidelines.
Umbilical Hernia Umbilical hernia (HP:0001537)
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"Isolated central CH due to biallelic TSHβ gene mutations is associated with severe hypothyroidism and characterized by the typical manifestations of CH (hypotonia, jaundice, umbilical hernia, macroglossia, etc.)."
The consensus guidelines explicitly list umbilical hernia as a typical manifestation of congenital hypothyroidism.
🧬

Genetic Associations

10
PAX8
Show evidence (2 references)
PMID:41303336 SUPPORT Human Clinical
"Mutations in ten genes involved in thyroid gland development during embryogenesis, TSHR, PAX8, NKX2-1, NKX2-5, FOXE1, JAG1, NTN1, GLIS3, CDC8A, and TUBB1, have been identified in cohorts of patients with thyroid dysgenesis."
Lists PAX8 among the established thyroid dysgenesis genes.
PMID:29650690 SUPPORT Human Clinical
"eight mutations in four genes (FOXE1, NKX2-1, PAX8 and HHEX) that lead to thyroid dysgenesis were identified in eight probands."
Identifies PAX8 mutations in probands with thyroid dysgenesis in a Chinese cohort.
TSHR
Show evidence (1 reference)
PMID:41303336 SUPPORT Human Clinical
"Mutations in ten genes involved in thyroid gland development during embryogenesis, TSHR, PAX8, NKX2-1, NKX2-5, FOXE1, JAG1, NTN1, GLIS3, CDC8A, and TUBB1, have been identified in cohorts of patients with thyroid dysgenesis."
Lists TSHR among established thyroid dysgenesis genes.
NKX2-1
Show evidence (1 reference)
PMID:41303336 SUPPORT Human Clinical
"Mutations in ten genes involved in thyroid gland development during embryogenesis, TSHR, PAX8, NKX2-1, NKX2-5, FOXE1, JAG1, NTN1, GLIS3, CDC8A, and TUBB1, have been identified in cohorts of patients with thyroid dysgenesis."
Lists NKX2-1 among established thyroid dysgenesis genes.
FOXE1
Show evidence (1 reference)
PMID:29650690 SUPPORT Human Clinical
"eight mutations in four genes (FOXE1, NKX2-1, PAX8 and HHEX) that lead to thyroid dysgenesis were identified in eight probands."
Identifies FOXE1 among genes with mutations leading to thyroid dysgenesis.
TPO
Autosomal recessive
Show evidence (1 reference)
PMID:37390946 SUPPORT Human Clinical
"the TSH levels and initial L-T4 dose were significantly higher in "TPO biallelic variants" group than those in "DUOX2 and TSHR biallelic variants" groups."
Demonstrates TPO biallelic variants cause more severe biochemical hypothyroidism than DUOX2 or TSHR variants.
DUOX2
Autosomal recessive
Show evidence (1 reference)
PMID:29650690 SUPPORT Human Clinical
"This study identified previously reported causative genes for 57/110 Chinese patients and revealed DUOX2 was the most frequently mutated gene in these patients."
Identifies DUOX2 as the most frequently mutated CH gene in a Chinese cohort of 110 patients.
TG
Autosomal recessive
Show evidence (1 reference)
PMID:29650690 SUPPORT Human Clinical
"Our results showed that 57 patients (51.82%) carried biallelic mutations (containing compound heterozygous mutations and homozygous mutations) in six genes (DUOX2, DUOXA2, DUOXA1, TG, TPO and TSHR) involved in thyroid hormone synthesis."
Identifies TG among the six genes with biallelic mutations in CH patients.
SLC5A5
Show evidence (1 reference)
PMID:29650690 SUPPORT Human Clinical
"Thyroid dyshormonogenesis, which is caused by defects in thyroid hormone biosynthesis, accounts for approximately 10–15% of primary CH and is associated with the following genes: DUOX2, DUOXA2, DUOX1, TPO, TG, SLC26A4, SLC5A5 and TSHR"
Explicitly lists SLC5A5 among the genes associated with thyroid dyshormonogenesis.
DUOXA2
Autosomal recessive
Show evidence (1 reference)
PMID:29650690 SUPPORT Human Clinical
"Our results showed that 57 patients (51.82%) carried biallelic mutations (containing compound heterozygous mutations and homozygous mutations) in six genes (DUOX2, DUOXA2, DUOXA1, TG, TPO and TSHR) involved in thyroid hormone synthesis."
Identifies DUOXA2 among the six genes with biallelic mutations in thyroid hormone synthesis in CH patients.
SLC26A4
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"Pendred syndrome due to mutations in the SLC26A4 gene (OMIM No. 274600), with or without goiter, should be considered in case of congenital sensorineural hearing loss."
Guidelines identify SLC26A4 as a cause of syndromic CH (Pendred syndrome) with hearing loss and goiter.
💊

Treatments

3
Levothyroxine Replacement
Action: Pharmacotherapy NCIT:C15986
Agent: levothyroxine ↗
Levothyroxine is the standard treatment for congenital hypothyroidism. Early initiation within 2 weeks of birth at doses of 10-15 mcg/kg/day is critical to prevent irreversible neurodevelopmental damage.
Mechanism Target:
MODULATES Neurodevelopmental Impairment from Thyroid Hormone Deficiency — Exogenous levothyroxine bypasses the endogenous thyroid hormone deficiency, preventing neurodevelopmental impairment when started early.
Show evidence (1 reference)
PMID:29405999 SUPPORT Human Clinical
"Early and adequate treatment with levothyroxine results in excellent neurodevelopmental outcomes for most patients with congenital hypothyroidism."
Directly supports the efficacy of early levothyroxine treatment in preventing neurodevelopmental morbidity.
Target Phenotypes: Congenital hypothyroidism ↗
Show evidence (2 references)
PMID:33272083 SUPPORT Human Clinical
"LT4 treatment should be started as soon as possible, not later than 2 weeks after birth or immediately after confirmatory (serum) thyroid function testing"
Consensus guideline recommendation for early levothyroxine treatment.
PMID:25729683 SUPPORT Human Clinical
"Treatment should be started promptly and infant should be rendered euthyroid as early as possible, as there is an inverse relationship between intelligence quotient (IQ) and the age at diagnosis."
Demonstrates the critical importance of early treatment with the inverse IQ-diagnosis age relationship.
Newborn Screening
Action: disease screening MAXO:0000124
Universal newborn screening programs detect congenital hypothyroidism through TSH and/or T4 measurement from heel-prick dried blood spots, enabling early treatment before clinical symptoms develop.
Target Phenotypes: Congenital hypothyroidism ↗
Show evidence (2 references)
PMID:33272083 SUPPORT Human Clinical
"Early detection and treatment of CH through neonatal screening prevent irreversible neurodevelopmental delay and optimize its developmental outcome"
Strong recommendation for universal newborn screening from the consensus guidelines.
PMID:33272083 SUPPORT Human Clinical
"Neonatal screening for CH has almost eliminated the profound negative effects of TH deficiency on growth and neurodevelopment (cretinism) in those countries where it has been established."
Documents the public health success of newborn screening in preventing cretinism.
Genetic Counseling
Action: genetic counseling MAXO:0000079
Targeted genetic counseling for families with congenital hypothyroidism, particularly for dyshormonogenesis (25% recurrence risk for autosomal recessive forms) and familial thyroid dysgenesis.
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"Counseling should include explaining inheritance and the risk of recurrence of the patient's primary or central form of CH, based on the CH subtype, the family history, and, if known, the (genetic) cause"
Guideline recommendation for targeted genetic counseling in CH families.
🔬

Biochemical Markers

2
Elevated TSH (Elevated)
Context: Newborn screening and diagnostic evaluation
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"the most sensitive test for detecting primary CH is measurement of thyrotropin (TSH)"
Confirms elevated TSH as the primary screening and diagnostic marker for primary congenital hypothyroidism.
Low Free Thyroxine (Decreased)
Context: Diagnostic evaluation
Show evidence (1 reference)
PMID:33272083 SUPPORT Human Clinical
"If the serum fT4 concentration is below and TSH clearly above the age-specific reference interval, then levothyroxine (LT4) treatment should be started immediately"
Confirms low fT4 as a key diagnostic finding triggering treatment.
{ }

Source YAML

click to show 
name: Congenital Hypothyroidism
creation_date: '2026-05-14T20:54:37Z'
updated_date: '2026-05-19T15:00:00Z'
category: Complex
disease_term:
  preferred_term: congenital hypothyroidism
  term:
    id: MONDO:0018612
    label: congenital hypothyroidism
parents:
- hypothyroidism
description: Congenital hypothyroidism is thyroid hormone deficiency present at birth
  and is one of the most common preventable causes of intellectual disability worldwide.
  The primary form, caused by thyroid dysgenesis or dyshormonogenesis, accounts for
  the vast majority of cases with an incidence of 1 in 2000 to 1 in 3000. Universal
  newborn screening enables early detection and treatment with levothyroxine, which
  prevents irreversible neurodevelopmental damage when initiated within the first
  two weeks of life.
has_subtypes:
- name: Permanent Primary
  display_name: Permanent Primary Congenital Hypothyroidism
  description: Permanent thyroid hormone deficiency due to thyroid gland dysgenesis
    (agenesis, ectopy, hypoplasia) or dyshormonogenesis, requiring lifelong levothyroxine
    replacement. Thyroid dysgenesis accounts for 65-85% of primary CH cases.
  subtype_term:
    preferred_term: permanent congenital hypothyroidism
    term:
      id: MONDO:0016408
      label: permanent congenital hypothyroidism
- name: Transient
  display_name: Transient Congenital Hypothyroidism
  description: Temporary thyroid hormone deficiency at birth that resolves spontaneously,
    commonly due to maternal antithyroid antibodies, iodine excess or deficiency,
    or prematurity.
  subtype_term:
    preferred_term: transient congenital hypothyroidism
    term:
      id: MONDO:0015792
      label: transient congenital hypothyroidism
- name: Central
  display_name: Central Congenital Hypothyroidism
  description: Congenital thyroid hormone deficiency caused by insufficient hypothalamic
    or pituitary stimulation of the thyroid gland, with low free T4 and non-elevated
    TSH. Incidence approximately 1 in 16,000.
  subtype_term:
    preferred_term: central congenital hypothyroidism
    term:
      id: MONDO:0016410
      label: central congenital hypothyroidism
- name: Dyshormonogenesis
  display_name: Familial Thyroid Dyshormonogenesis
  description: Autosomal recessive defects in thyroid hormone synthesis enzymes and
    transporters (TPO, TG, DUOX2, SLC5A5, SLC26A4) causing goitrous congenital hypothyroidism.
  subtype_term:
    preferred_term: familial thyroid dyshormonogenesis
    term:
      id: MONDO:0010132
      label: familial thyroid dyshormonogenesis
inheritance:
- name: Autosomal recessive inheritance
  description: Dyshormonogenesis subtypes (TPO, TG, DUOX2, DUOXA2, SLC5A5, SLC26A4
    mutations) follow autosomal recessive inheritance with 25% recurrence risk.
  inheritance_term:
    preferred_term: Autosomal recessive inheritance
    term:
      id: HP:0000007
      label: Autosomal recessive inheritance
  evidence:
  - reference: PMID:29650690
    reference_title: The genetic characteristics of congenital hypothyroidism in China
      by comprehensive screening of 21 candidate genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Autosomal recessive inheritance of CH caused by mutations in DUOX2,
      DUOXA2, TG and TPO was confirmed by analysis of 22 family pedigrees.
    explanation: Family pedigree analysis confirms autosomal recessive inheritance
      for dyshormonogenesis genes.
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Counseling should include explaining inheritance and the risk of recurrence
      of the patient's primary or central form of CH, based on the CH subtype, the
      family history, and, if known, the (genetic) cause
    explanation: Guidelines recommend counseling on inheritance including recurrence
      risk for autosomal recessive forms.
- name: Sporadic occurrence
  description: Thyroid dysgenesis, the most common cause of primary CH, is typically
    sporadic with unclear inheritance. Monogenic, polygenic, and multifactorial
    inheritance have all been proposed.
  evidence:
  - reference: PMID:29650690
    reference_title: The genetic characteristics of congenital hypothyroidism in China
      by comprehensive screening of 21 candidate genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: eight mutations in four genes (FOXE1, NKX2-1, PAX8 and HHEX) that lead
      to thyroid dysgenesis were identified in eight probands. These mutations were
      heterozygous in all cases and hypothyroidism was not observed in parents of
      these probands.
    explanation: Heterozygous mutations in thyroid dysgenesis genes with unaffected
      parents suggest complex or sporadic rather than simple dominant inheritance.
prevalence:
- population: Worldwide (primary CH)
  percentage: 0.04
  notes: Incidence of primary CH is 1 in 2000 to 1 in 3000 newborns depending on
    screening strategy.
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: the incidence of primary CH lies between 1 in 3000 and 1 in 2000; the
      highest reported incidence of central CH is ∼1 in 16,000
    explanation: Consensus guidelines provide incidence ranges for primary and central
      CH from multiple screening programs.
- population: Worldwide (central CH)
  percentage: 0.006
  notes: Incidence of central CH is approximately 1 in 16,000 newborns.
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: the incidence of primary CH lies between 1 in 3000 and 1 in 2000; the
      highest reported incidence of central CH is ∼1 in 16,000
    explanation: Central CH has a lower incidence than primary CH.
pathophysiology:
- name: Thyroid Gland Dysgenesis
  description: The most common cause of permanent primary congenital hypothyroidism
    is abnormal thyroid gland development, including thyroid agenesis, ectopy, or
    hypoplasia, resulting in insufficient thyroid hormone production from birth. Thyroid
    dysgenesis accounts for 65-85% of primary CH cases.
  subtypes:
  - Permanent Primary
  locations:
  - preferred_term: thyroid gland
    term:
      id: UBERON:0002046
      label: thyroid gland
  cell_types:
  - preferred_term: thyroid follicular cell
    term:
      id: CL:0002257
      label: epithelial cell of thyroid gland
  biological_processes:
  - preferred_term: Thyroid gland development
    term:
      id: GO:0030878
      label: thyroid gland development
    modifier: ABNORMAL
  - preferred_term: Thyroid hormone generation
    term:
      id: GO:0006590
      label: thyroid hormone generation
    modifier: DECREASED
  evidence:
  - reference: PMID:41303336
    reference_title: 'Molecular Genetics of Primary Congenital Hypothyroidism: Established
      and Emerging Contributors to Thyroid Dysgenesis.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The primary form of CH is attributable to thyroid dysgenesis (agenesis,
      hypoplasia, or ectopy) in 65-85% of cases, with the remaining cases being attributed
      to dyshormogenesis.
    explanation: Directly states the proportion of primary CH attributable to thyroid
      dysgenesis and its subtypes.
  - reference: PMID:25729683
    reference_title: Congenital hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: In the majority of patients, CH is caused by an abnormal development
      of the thyroid gland (thyroid dysgenesis) that is a sporadic disorder and accounts
      for 85% of cases and the remaining 15% of cases are caused by dyshormonogenesis.
    explanation: Confirms thyroid dysgenesis as the predominant cause of CH and provides
      the 85%/15% proportion.
  downstream:
  - target: Neurodevelopmental Impairment from Thyroid Hormone Deficiency
    causal_link_type: DIRECT
    description: Insufficient thyroid hormone production from dysgenetic thyroid tissue
      leads to thyroid hormone deficiency during critical periods of brain development.
    evidence:
    - reference: PMID:29405999
      reference_title: Congenital Hypothyroidism.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Congenital hypothyroidism is common and can cause severe neurodevelopmental
        morbidity.
      explanation: Links thyroid hormone deficiency from any cause to neurodevelopmental
        impairment.
- name: Defective Thyroid Hormone Biosynthesis
  description: Inborn errors of thyroid hormone synthesis due to mutations in genes
    encoding enzymes and transporters required for iodide organification and thyroid
    hormone biosynthesis (TPO, TG, DUOX2, SLC5A5, SLC26A4), typically resulting in
    goitrous hypothyroidism.
  subtypes:
  - Dyshormonogenesis
  locations:
  - preferred_term: thyroid gland
    term:
      id: UBERON:0002046
      label: thyroid gland
  cell_types:
  - preferred_term: thyroid follicular cell
    term:
      id: CL:0002257
      label: epithelial cell of thyroid gland
  biological_processes:
  - preferred_term: Thyroid hormone generation
    term:
      id: GO:0006590
      label: thyroid hormone generation
    modifier: DECREASED
  evidence:
  - reference: PMID:29650690
    reference_title: The genetic characteristics of congenital hypothyroidism in China
      by comprehensive screening of 21 candidate genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Our results showed that 57 patients (51.82%) carried biallelic mutations
      (containing compound heterozygous mutations and homozygous mutations) in six
      genes (DUOX2, DUOXA2, DUOXA1, TG, TPO and TSHR) involved in thyroid hormone
      synthesis.
    explanation: Demonstrates that dyshormonogenesis genes are the most common genetic
      cause identified in a comprehensive screening study.
  - reference: PMID:37390946
    reference_title: Clinical, biochemical characteristics and genotype-phenotype
      analysis of congenital hypothyroidism diagnosed by newborn screening in China.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: DUOX2 gene had the highest variant rate, followed by TG, TPO and TSHR
      gene.
    explanation: Confirms the relative frequency of dyshormonogenesis gene variants
      in a newborn screening cohort.
  downstream:
  - target: Neurodevelopmental Impairment from Thyroid Hormone Deficiency
    causal_link_type: DIRECT
    description: Impaired thyroid hormone synthesis leads to the same downstream thyroid
      hormone deficiency as dysgenesis, though the thyroid gland is present and often
      goitrous.
    evidence:
    - reference: PMID:29405999
      reference_title: Congenital Hypothyroidism.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Congenital hypothyroidism is common and can cause severe neurodevelopmental
        morbidity.
      explanation: Links thyroid hormone deficiency from any cause to neurodevelopmental
        impairment.
- name: Impaired Hypothalamic-Pituitary TSH Drive
  description: Deficient hypothalamic TRH signaling or pituitary thyrotroph dysfunction
    leads to inadequate TSH secretion, producing low free T4 with inappropriately
    low or normal TSH.
  subtypes:
  - Central
  locations:
  - preferred_term: hypothalamus-pituitary axis
    term:
      id: UBERON:0004092
      label: hypothalamus-pituitary axis
  cell_types:
  - preferred_term: thyrotroph
    term:
      id: CL:0000476
      label: thyrotroph
  biological_processes:
  - preferred_term: Thyroid-stimulating hormone secretion
    term:
      id: GO:0070460
      label: thyroid-stimulating hormone secretion
    modifier: DECREASED
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: If the serum fT4 is low, and TSH is low, normal or slightly elevated,
      the diagnosis central CH should be considered
    explanation: The consensus guidelines describe the biochemical pattern of central
      CH reflecting inadequate TSH drive.
  downstream:
  - target: Neurodevelopmental Impairment from Thyroid Hormone Deficiency
    causal_link_type: DIRECT
    description: Inadequate TSH drive results in insufficient thyroid hormone production,
      causing the same downstream neurodevelopmental risk.
    evidence:
    - reference: PMID:29405999
      reference_title: Congenital Hypothyroidism.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Congenital hypothyroidism is common and can cause severe neurodevelopmental
        morbidity.
      explanation: Links thyroid hormone deficiency from any cause to neurodevelopmental
        impairment.
- name: Transient Thyroid Dysfunction
  description: Transient congenital hypothyroidism results from reversible disruption
    of thyroid function, most commonly due to transplacental passage of maternal TSH
    receptor-blocking antibodies, exposure to excess iodine, or hypothalamic-pituitary-thyroid
    axis immaturity in premature infants.
  subtypes:
  - Transient
  biological_processes:
  - preferred_term: Thyroid hormone generation
    term:
      id: GO:0006590
      label: thyroid hormone generation
    modifier: DECREASED
  evidence:
  - reference: PMID:20537182
    reference_title: Congenital hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Transient CH most commonly occurs in preterm infants born in areas of
      endemic iodine deficiency.
    explanation: Identifies prematurity and iodine deficiency as common causes of
      transient CH.
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: the prevalence of transient CH has steadily increased. In a number of
      studies, factors have been identified that increase the likelihood of transient
      disease, such as sex (more often in boys)
    explanation: Guidelines document the increasing prevalence and risk factors for
      transient CH.
  downstream:
  - target: Neurodevelopmental Impairment from Thyroid Hormone Deficiency
    causal_link_type: DIRECT
    description: Even transient thyroid hormone deficiency during critical neonatal
      brain development may cause neurodevelopmental harm if untreated.
    evidence:
    - reference: PMID:29405999
      reference_title: Congenital Hypothyroidism.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Congenital hypothyroidism is common and can cause severe neurodevelopmental
        morbidity.
      explanation: Links thyroid hormone deficiency from any cause to neurodevelopmental
        impairment.
- name: Neurodevelopmental Impairment from Thyroid Hormone Deficiency
  description: Thyroid hormone is indispensable for brain development during fetal
    life and the first 2-3 years. Deficiency during this critical period causes irreversible
    neurodevelopmental damage if untreated, historically known as cretinism.
  locations:
  - preferred_term: brain
    term:
      id: UBERON:0000955
      label: brain
  cell_types:
  - preferred_term: neuron
    term:
      id: CL:0000540
      label: neuron
  biological_processes:
  - preferred_term: Brain development
    term:
      id: GO:0007420
      label: brain development
    modifier: ABNORMAL
  evidence:
  - reference: PMID:29405999
    reference_title: Congenital Hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Congenital hypothyroidism is common and can cause severe neurodevelopmental
      morbidity.
    explanation: Directly states the neurodevelopmental consequence of congenital
      hypothyroidism.
  - reference: PMID:25729683
    reference_title: Congenital hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: delayed diagnosis leads to the most severe outcome of CH, mental retardation,
      emphasizing the importance of neonatal screening.
    explanation: Confirms that delayed diagnosis leads to irreversible intellectual
      disability.
phenotypes:
- category: Clinical
  name: Congenital Hypothyroidism
  description: Thyroid hormone deficiency present at birth, detectable by newborn
    screening.
  phenotype_term:
    preferred_term: Congenital hypothyroidism
    term:
      id: HP:0000851
      label: Congenital hypothyroidism
  diagnostic: true
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The incidence of CH partly depends on the screening strategy; based on
      data from a number of screening programs, the incidence of primary CH lies between
      1 in 3000 and 1 in 2000; the highest reported incidence of central CH is ∼1
      in 16,000
    explanation: Provides the incidence of primary and central congenital hypothyroidism
      from the consensus guidelines.
- category: Clinical
  name: Prolonged Neonatal Jaundice
  description: Prolonged jaundice beyond the first two weeks of life is a common early
    clinical sign of congenital hypothyroidism in neonates.
  phenotype_term:
    preferred_term: Prolonged neonatal jaundice
    term:
      id: HP:0006579
      label: Prolonged neonatal jaundice
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Isolated central CH due to biallelic TSHβ gene mutations is associated
      with severe hypothyroidism and characterized by the typical manifestations of
      CH (hypotonia, jaundice, umbilical hernia, macroglossia, etc.).
    explanation: The consensus guidelines list jaundice as a typical manifestation
      of congenital hypothyroidism.
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: we recommend endocrine testing in all neonates with a familial history
      of central CH, or signs or symptoms of congenital hypopituitarism, for example,
      micropenis with undescended testes, hypoglycemia, prolonged jaundice, or unexplained
      failure to thrive.
    explanation: Guidelines specifically mention prolonged jaundice as a clinical
      sign warranting endocrine testing for congenital hypothyroidism.
- category: Clinical
  name: Feeding Difficulties
  description: Feeding difficulties in the neonatal period are an early sign of congenital
    hypothyroidism.
  phenotype_term:
    preferred_term: Feeding difficulties
    term:
      id: HP:0011968
      label: Feeding difficulties
  evidence:
  - reference: PMID:20537182
    reference_title: Congenital hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Common symptoms include decreased activity and increased sleep, feeding
      difficulty, constipation, and prolonged jaundice.
    explanation: Lists feeding difficulty as a common symptom of congenital hypothyroidism.
- category: Clinical
  name: Macroglossia
  description: Enlarged tongue is a classic clinical feature of untreated congenital
    hypothyroidism.
  phenotype_term:
    preferred_term: Macroglossia
    term:
      id: HP:0000158
      label: Macroglossia
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Isolated central CH due to biallelic TSHβ gene mutations is associated
      with severe hypothyroidism and characterized by the typical manifestations of
      CH (hypotonia, jaundice, umbilical hernia, macroglossia, etc.).
    explanation: The consensus guidelines explicitly list macroglossia as a typical
      manifestation of congenital hypothyroidism.
- category: Clinical
  name: Hypotonia
  description: Decreased muscle tone is commonly observed in infants with congenital
    hypothyroidism.
  phenotype_term:
    preferred_term: Hypotonia
    term:
      id: HP:0001252
      label: Hypotonia
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Isolated central CH due to biallelic TSHβ gene mutations is associated
      with severe hypothyroidism and characterized by the typical manifestations of
      CH (hypotonia, jaundice, umbilical hernia, macroglossia, etc.).
    explanation: The consensus guidelines explicitly list hypotonia as a typical manifestation
      of congenital hypothyroidism.
- category: Clinical
  name: Intellectual Disability
  description: If untreated, congenital hypothyroidism leads to intellectual disability
    due to the critical role of thyroid hormone in brain development.
  phenotype_term:
    preferred_term: Intellectual disability
    term:
      id: HP:0001249
      label: Intellectual disability
  evidence:
  - reference: PMID:25729683
    reference_title: Congenital hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Congenital hypothyroidism (CH) is the one of the most common preventable
      cause of mental retardation.
    explanation: Directly identifies intellectual disability as the most severe preventable
      outcome of untreated congenital hypothyroidism.
- category: Clinical
  name: Short Stature
  description: Growth failure and short stature occur in inadequately treated congenital
    hypothyroidism.
  phenotype_term:
    preferred_term: Short stature
    term:
      id: HP:0004322
      label: Short stature
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: PARTIAL
    evidence_source: HUMAN_CLINICAL
    snippet: Adequately treated children with nonsyndromic CH have normal growth and
      puberty, and their fertility does not differ from individuals who do not have
      CH
    explanation: Indirectly supports short stature as a phenotype by stating that
      adequately treated CH results in normal growth, implying untreated CH leads
      to growth failure.
- category: Clinical
  name: Goiter
  description: Thyroid enlargement occurs in dyshormonogenesis subtypes where the
    gland is present but hormone synthesis is impaired, and may develop nodules requiring
    monitoring.
  subtype: Dyshormonogenesis
  phenotype_term:
    preferred_term: Goiter
    term:
      id: HP:0000853
      label: Goiter
  evidence:
  - reference: PMID:37390946
    reference_title: Clinical, biochemical characteristics and genotype-phenotype
      analysis of congenital hypothyroidism diagnosed by newborn screening in China.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: The "DUOX2 biallelic variants" group was associated with "Goiter"
    explanation: Demonstrates the association of goiter with dyshormonogenesis gene
      variants, specifically DUOX2 biallelic mutations.
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Children and adolescents with primary CH due to dyshomonogenesis may
      develop goiter and nodules; in these cases, serum TSH should be carefully targeted
      in the lower part of normal range and periodical ultrasound investigation is
      recommended to monitor thyroid volume
    explanation: Confirms goiter and nodule development in dyshormonogenesis and recommends
      monitoring.
- category: Clinical
  name: Umbilical Hernia
  description: Umbilical hernia is a classic clinical sign of congenital hypothyroidism
    in newborns.
  phenotype_term:
    preferred_term: Umbilical hernia
    term:
      id: HP:0001537
      label: Umbilical hernia
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Isolated central CH due to biallelic TSHβ gene mutations is associated
      with severe hypothyroidism and characterized by the typical manifestations of
      CH (hypotonia, jaundice, umbilical hernia, macroglossia, etc.).
    explanation: The consensus guidelines explicitly list umbilical hernia as a typical
      manifestation of congenital hypothyroidism.
- category: Clinical
  name: Constipation
  description: Constipation is a common clinical feature in infants with congenital
    hypothyroidism.
  phenotype_term:
    preferred_term: Constipation
    term:
      id: HP:0002019
      label: Constipation
  evidence:
  - reference: PMID:20537182
    reference_title: Congenital hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Common symptoms include decreased activity and increased sleep, feeding
      difficulty, constipation, and prolonged jaundice.
    explanation: Lists constipation as a common symptom of congenital hypothyroidism.
- category: Clinical
  name: Large Fontanelles
  description: Widely open anterior fontanelle or large posterior fontanelle is a
    classic sign of congenital hypothyroidism in newborns.
  phenotype_term:
    preferred_term: Large fontanelles
    term:
      id: HP:0000239
      label: Large fontanelles
  evidence:
  - reference: PMID:20537182
    reference_title: Congenital hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: On examination, common signs include myxedematous facies, large fontanels,
      macroglossia, a distended abdomen with umbilical hernia, and hypotonia.
    explanation: Lists large fontanels as a common examination finding in congenital
      hypothyroidism.
- category: Clinical
  name: Dry Skin
  description: Dry, mottled skin is observed in infants with congenital hypothyroidism.
  phenotype_term:
    preferred_term: Dry skin
    term:
      id: HP:0000958
      label: Dry skin
  evidence:
  - reference: PMID:20537182
    reference_title: Congenital hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: On examination, common signs include myxedematous facies, large fontanels,
      macroglossia, a distended abdomen with umbilical hernia, and hypotonia.
    explanation: Myxedematous facies in CH includes dry, thickened skin characteristic
      of hypothyroidism.
- category: Clinical
  name: Failure to Thrive
  description: Poor weight gain and failure to thrive may be present in untreated
    or undertreated infants with congenital hypothyroidism.
  phenotype_term:
    preferred_term: Failure to thrive
    term:
      id: HP:0001508
      label: Failure to thrive
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: we recommend endocrine testing in all neonates with a familial history
      of central CH, or signs or symptoms of congenital hypopituitarism, for example,
      micropenis with undescended testes, hypoglycemia, prolonged jaundice, or unexplained
      failure to thrive.
    explanation: The guidelines identify failure to thrive as a clinical sign prompting
      evaluation for congenital hypothyroidism.
biochemical:
- name: Elevated TSH
  presence: Elevated
  subtype: Permanent Primary
  context: Newborn screening and diagnostic evaluation
  notes: Markedly elevated TSH with low free T4 is the hallmark of primary congenital
    hypothyroidism and the basis of TSH-based newborn screening programs.
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: the most sensitive test for detecting primary CH is measurement of thyrotropin
      (TSH)
    explanation: Confirms elevated TSH as the primary screening and diagnostic marker
      for primary congenital hypothyroidism.
- name: Low Free Thyroxine
  presence: Decreased
  context: Diagnostic evaluation
  notes: Low serum free T4 is present in all forms of congenital hypothyroidism, whether
    primary or central.
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: If the serum fT4 concentration is below and TSH clearly above the age-specific
      reference interval, then levothyroxine (LT4) treatment should be started immediately
    explanation: Confirms low fT4 as a key diagnostic finding triggering treatment.
genetic:
- name: PAX8
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Permanent Primary
  gene_term:
    preferred_term: PAX8
    term:
      id: hgnc:8622
      label: PAX8
  notes: PAX8 mutations cause thyroid dysgenesis through impaired thyroid gland development.
  evidence:
  - reference: PMID:41303336
    reference_title: 'Molecular Genetics of Primary Congenital Hypothyroidism: Established
      and Emerging Contributors to Thyroid Dysgenesis.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Mutations in ten genes involved in thyroid gland development during embryogenesis,
      TSHR, PAX8, NKX2-1, NKX2-5, FOXE1, JAG1, NTN1, GLIS3, CDC8A, and TUBB1, have
      been identified in cohorts of patients with thyroid dysgenesis.
    explanation: Lists PAX8 among the established thyroid dysgenesis genes.
  - reference: PMID:29650690
    reference_title: The genetic characteristics of congenital hypothyroidism in China
      by comprehensive screening of 21 candidate genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: eight mutations in four genes (FOXE1, NKX2-1, PAX8 and HHEX) that lead
      to thyroid dysgenesis were identified in eight probands.
    explanation: Identifies PAX8 mutations in probands with thyroid dysgenesis in
      a Chinese cohort.
- name: TSHR
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Permanent Primary
  gene_term:
    preferred_term: TSHR
    term:
      id: hgnc:12373
      label: TSHR
  notes: Loss-of-function TSHR mutations cause TSH resistance. TSHR is also classified
    as a thyroid dysgenesis gene.
  evidence:
  - reference: PMID:41303336
    reference_title: 'Molecular Genetics of Primary Congenital Hypothyroidism: Established
      and Emerging Contributors to Thyroid Dysgenesis.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Mutations in ten genes involved in thyroid gland development during embryogenesis,
      TSHR, PAX8, NKX2-1, NKX2-5, FOXE1, JAG1, NTN1, GLIS3, CDC8A, and TUBB1, have
      been identified in cohorts of patients with thyroid dysgenesis.
    explanation: Lists TSHR among established thyroid dysgenesis genes.
- name: NKX2-1
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Permanent Primary
  gene_term:
    preferred_term: NKX2-1
    term:
      id: hgnc:11825
      label: NKX2-1
  notes: NKX2-1 (also known as TTF-1) mutations cause thyroid dysgenesis and may be
    associated with brain-lung-thyroid syndrome.
  evidence:
  - reference: PMID:41303336
    reference_title: 'Molecular Genetics of Primary Congenital Hypothyroidism: Established
      and Emerging Contributors to Thyroid Dysgenesis.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Mutations in ten genes involved in thyroid gland development during embryogenesis,
      TSHR, PAX8, NKX2-1, NKX2-5, FOXE1, JAG1, NTN1, GLIS3, CDC8A, and TUBB1, have
      been identified in cohorts of patients with thyroid dysgenesis.
    explanation: Lists NKX2-1 among established thyroid dysgenesis genes.
- name: FOXE1
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Permanent Primary
  gene_term:
    preferred_term: FOXE1
    term:
      id: hgnc:3806
      label: FOXE1
  notes: FOXE1 (also known as TTF-2) mutations cause thyroid dysgenesis, often associated
    with cleft palate and choanal atresia (Bamforth-Lazarus syndrome).
  evidence:
  - reference: PMID:29650690
    reference_title: The genetic characteristics of congenital hypothyroidism in China
      by comprehensive screening of 21 candidate genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: eight mutations in four genes (FOXE1, NKX2-1, PAX8 and HHEX) that lead
      to thyroid dysgenesis were identified in eight probands.
    explanation: Identifies FOXE1 among genes with mutations leading to thyroid dysgenesis.
- name: TPO
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Dyshormonogenesis
  gene_term:
    preferred_term: TPO
    term:
      id: hgnc:12015
      label: TPO
  inheritance:
  - name: Autosomal recessive
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:29650690
      reference_title: The genetic characteristics of congenital hypothyroidism in
        China by comprehensive screening of 21 candidate genes.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Autosomal recessive inheritance of CH caused by mutations in DUOX2,
        DUOXA2, TG and TPO was confirmed by analysis of 22 family pedigrees.
      explanation: Confirms autosomal recessive inheritance for TPO-related CH through
        family pedigree analysis.
  notes: TPO mutations cause impaired iodide organification, leading to goitrous congenital
    hypothyroidism.
  evidence:
  - reference: PMID:37390946
    reference_title: Clinical, biochemical characteristics and genotype-phenotype
      analysis of congenital hypothyroidism diagnosed by newborn screening in China.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: the TSH levels and initial L-T4 dose were significantly higher in "TPO
      biallelic variants" group than those in "DUOX2 and TSHR biallelic variants"
      groups.
    explanation: Demonstrates TPO biallelic variants cause more severe biochemical
      hypothyroidism than DUOX2 or TSHR variants.
- name: DUOX2
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Dyshormonogenesis
  gene_term:
    preferred_term: DUOX2
    term:
      id: hgnc:13273
      label: DUOX2
  inheritance:
  - name: Autosomal recessive
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:29650690
      reference_title: The genetic characteristics of congenital hypothyroidism in
        China by comprehensive screening of 21 candidate genes.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Autosomal recessive inheritance of CH caused by mutations in DUOX2,
        DUOXA2, TG and TPO was confirmed by analysis of 22 family pedigrees.
      explanation: Confirms autosomal recessive inheritance for DUOX2-related CH.
  notes: DUOX2 mutations cause defective hydrogen peroxide generation required for
    thyroid hormone synthesis. DUOX2 is the most frequently mutated gene in CH patients
    in Chinese populations.
  evidence:
  - reference: PMID:29650690
    reference_title: The genetic characteristics of congenital hypothyroidism in China
      by comprehensive screening of 21 candidate genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: This study identified previously reported causative genes for 57/110
      Chinese patients and revealed DUOX2 was the most frequently mutated gene in
      these patients.
    explanation: Identifies DUOX2 as the most frequently mutated CH gene in a Chinese
      cohort of 110 patients.
- name: TG
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Dyshormonogenesis
  gene_term:
    preferred_term: TG
    term:
      id: hgnc:11764
      label: TG
  inheritance:
  - name: Autosomal recessive
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:29650690
      reference_title: The genetic characteristics of congenital hypothyroidism in
        China by comprehensive screening of 21 candidate genes.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Autosomal recessive inheritance of CH caused by mutations in DUOX2,
        DUOXA2, TG and TPO was confirmed by analysis of 22 family pedigrees.
      explanation: Confirms autosomal recessive inheritance for TG-related CH.
  notes: Thyroglobulin gene mutations cause defective thyroglobulin synthesis, a substrate
    for thyroid hormone production.
  evidence:
  - reference: PMID:29650690
    reference_title: The genetic characteristics of congenital hypothyroidism in China
      by comprehensive screening of 21 candidate genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Our results showed that 57 patients (51.82%) carried biallelic mutations
      (containing compound heterozygous mutations and homozygous mutations) in six
      genes (DUOX2, DUOXA2, DUOXA1, TG, TPO and TSHR) involved in thyroid hormone
      synthesis.
    explanation: Identifies TG among the six genes with biallelic mutations in CH
      patients.
- name: SLC5A5
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Dyshormonogenesis
  gene_term:
    preferred_term: SLC5A5
    term:
      id: hgnc:11040
      label: SLC5A5
  notes: SLC5A5 (sodium-iodide symporter) mutations cause defective iodide transport
    into thyroid follicular cells.
  evidence:
  - reference: PMID:29650690
    reference_title: The genetic characteristics of congenital hypothyroidism in China
      by comprehensive screening of 21 candidate genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: "Thyroid dyshormonogenesis, which is caused by defects in thyroid hormone
      biosynthesis, accounts for approximately 10–15% of primary CH and is associated
      with the following genes: DUOX2, DUOXA2, DUOX1, TPO, TG, SLC26A4, SLC5A5 and
      TSHR"
    explanation: Explicitly lists SLC5A5 among the genes associated with thyroid
      dyshormonogenesis.
- name: DUOXA2
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Dyshormonogenesis
  gene_term:
    preferred_term: DUOXA2
    term:
      id: hgnc:32698
      label: DUOXA2
  inheritance:
  - name: Autosomal recessive
    inheritance_term:
      preferred_term: Autosomal recessive inheritance
      term:
        id: HP:0000007
        label: Autosomal recessive inheritance
    evidence:
    - reference: PMID:29650690
      reference_title: The genetic characteristics of congenital hypothyroidism in
        China by comprehensive screening of 21 candidate genes.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Autosomal recessive inheritance of CH caused by mutations in DUOX2,
        DUOXA2, TG and TPO was confirmed by analysis of 22 family pedigrees.
      explanation: Confirms autosomal recessive inheritance for DUOXA2-related CH.
  notes: DUOXA2 is a maturation factor for DUOX2, required for proper DUOX2 function
    in hydrogen peroxide generation for thyroid hormone synthesis.
  evidence:
  - reference: PMID:29650690
    reference_title: The genetic characteristics of congenital hypothyroidism in China
      by comprehensive screening of 21 candidate genes.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Our results showed that 57 patients (51.82%) carried biallelic mutations
      (containing compound heterozygous mutations and homozygous mutations) in six
      genes (DUOX2, DUOXA2, DUOXA1, TG, TPO and TSHR) involved in thyroid hormone
      synthesis.
    explanation: Identifies DUOXA2 among the six genes with biallelic mutations
      in thyroid hormone synthesis in CH patients.
- name: SLC26A4
  relationship_type: CAUSATIVE
  presence: Present
  subtype: Dyshormonogenesis
  gene_term:
    preferred_term: SLC26A4
    term:
      id: hgnc:8818
      label: SLC26A4
  notes: SLC26A4 (pendrin) mutations cause Pendred syndrome with goiter, congenital
    hypothyroidism, and sensorineural hearing loss.
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Pendred syndrome due to mutations in the SLC26A4 gene (OMIM No. 274600),
      with or without goiter, should be considered in case of congenital sensorineural
      hearing loss.
    explanation: Guidelines identify SLC26A4 as a cause of syndromic CH (Pendred
      syndrome) with hearing loss and goiter.
treatments:
- name: Levothyroxine Replacement
  description: Levothyroxine is the standard treatment for congenital hypothyroidism.
    Early initiation within 2 weeks of birth at doses of 10-15 mcg/kg/day is critical
    to prevent irreversible neurodevelopmental damage.
  treatment_term:
    preferred_term: Pharmacotherapy
    term:
      id: NCIT:C15986
      label: Pharmacotherapy
    therapeutic_agent:
    - preferred_term: levothyroxine
      term:
        id: CHEBI:6446
        label: levothyroxine sodium anhydrous
  target_phenotypes:
  - preferred_term: Congenital hypothyroidism
    term:
      id: HP:0000851
      label: Congenital hypothyroidism
  target_mechanisms:
  - target: Neurodevelopmental Impairment from Thyroid Hormone Deficiency
    treatment_effect: MODULATES
    description: Exogenous levothyroxine bypasses the endogenous thyroid hormone deficiency,
      preventing neurodevelopmental impairment when started early.
    evidence:
    - reference: PMID:29405999
      reference_title: Congenital Hypothyroidism.
      supports: SUPPORT
      evidence_source: HUMAN_CLINICAL
      snippet: Early and adequate treatment with levothyroxine results in excellent
        neurodevelopmental outcomes for most patients with congenital hypothyroidism.
      explanation: Directly supports the efficacy of early levothyroxine treatment
        in preventing neurodevelopmental morbidity.
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: LT4 treatment should be started as soon as possible, not later than 2
      weeks after birth or immediately after confirmatory (serum) thyroid function
      testing
    explanation: Consensus guideline recommendation for early levothyroxine treatment.
  - reference: PMID:25729683
    reference_title: Congenital hypothyroidism.
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Treatment should be started promptly and infant should be rendered euthyroid
      as early as possible, as there is an inverse relationship between intelligence
      quotient (IQ) and the age at diagnosis.
    explanation: Demonstrates the critical importance of early treatment with the
      inverse IQ-diagnosis age relationship.
- name: Newborn Screening
  description: Universal newborn screening programs detect congenital hypothyroidism
    through TSH and/or T4 measurement from heel-prick dried blood spots, enabling
    early treatment before clinical symptoms develop.
  treatment_term:
    preferred_term: disease screening
    term:
      id: MAXO:0000124
      label: disease screening
  target_phenotypes:
  - preferred_term: Congenital hypothyroidism
    term:
      id: HP:0000851
      label: Congenital hypothyroidism
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Early detection and treatment of CH through neonatal screening prevent
      irreversible neurodevelopmental delay and optimize its developmental outcome
    explanation: Strong recommendation for universal newborn screening from the consensus
      guidelines.
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Neonatal screening for CH has almost eliminated the profound negative
      effects of TH deficiency on growth and neurodevelopment (cretinism) in those
      countries where it has been established.
    explanation: Documents the public health success of newborn screening in preventing
      cretinism.
- name: Genetic Counseling
  description: Targeted genetic counseling for families with congenital hypothyroidism,
    particularly for dyshormonogenesis (25% recurrence risk for autosomal recessive
    forms) and familial thyroid dysgenesis.
  treatment_term:
    preferred_term: genetic counseling
    term:
      id: MAXO:0000079
      label: genetic counseling
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Counseling should include explaining inheritance and the risk of recurrence
      of the patient's primary or central form of CH, based on the CH subtype, the
      family history, and, if known, the (genetic) cause
    explanation: Guideline recommendation for targeted genetic counseling in CH families.
diagnosis:
- name: Newborn screening (TSH-based)
  description: Universal newborn screening using TSH measurement from dried blood
    spots collected 48 hours after birth is the primary method of detecting primary
    congenital hypothyroidism.
  diagnosis_term:
    preferred_term: disease screening
    term:
      id: MAXO:0000124
      label: disease screening
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: Early detection and treatment of CH through neonatal screening prevent
      irreversible neurodevelopmental delay and optimize its developmental outcome
    explanation: Strong recommendation for universal newborn screening from consensus
      guidelines.
- name: Confirmatory serum thyroid function testing
  description: Confirmatory measurement of serum fT4 and TSH is required after an
    abnormal screening result. If serum TSH is >20 mU/L, treatment should start even
    if fT4 is normal.
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: If the serum fT4 concentration is below and TSH clearly above the age-specific
      reference interval, then levothyroxine (LT4) treatment should be started immediately
    explanation: Guidelines specify the confirmatory testing criteria for initiating
      treatment.
- name: Thyroid imaging
  description: Thyroid scintigraphy and/or ultrasonography to determine thyroid morphology
    (dysgenesis vs gland in situ), which informs the etiology and prognosis.
  diagnosis_term:
    preferred_term: nuclear medicine imaging procedure
    term:
      id: MAXO:0001321
      label: nuclear medicine imaging procedure
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: We recommend imaging of the thyroid gland using either radioisotope scanning
      (scintigraphy) with or without the perchlorate discharge test, or ultrasonography
      (US), or both
    explanation: Guidelines recommend thyroid imaging to determine the etiology of CH.
- name: Genetic testing
  description: Molecular genetic testing to identify causative mutations, particularly
    for dyshormonogenesis genes and thyroid dysgenesis transcription factors, informing
    genetic counseling.
  diagnosis_term:
    preferred_term: genetic testing
    term:
      id: MAXO:0000127
      label: genetic testing
  evidence:
  - reference: PMID:33272083
    reference_title: 'Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines
      Update.'
    supports: SUPPORT
    evidence_source: HUMAN_CLINICAL
    snippet: If genetic testing is performed, its aim should be improving diagnosis,
      treatment, or prognosis
    explanation: Guidelines support genetic testing when it informs clinical management.
datasets: []
📚

References & Deep Research

Deep Research

1
Congenital Hypothyroidism — Manual Literature Research ▸

Congenital Hypothyroidism — Manual Literature Research

Research Method

Manual PubMed search and literature review (no deep research API keys available). Searched PubMed for: congenital hypothyroidism review, thyroid dysgenesis genetics, thyroid dyshormonogenesis, newborn screening, levothyroxine treatment outcomes.

Key References Used

  1. PMID:33272083 — van Trotsenburg et al. (2021) "Congenital Hypothyroidism: A 2020-2021 Consensus Guidelines Update" — ENDO-ERN consensus guidelines. Comprehensive coverage of screening, diagnosis, treatment, and genetics.

  2. PMID:29405999 — Wassner (2018) "Congenital Hypothyroidism" — Review covering etiology (dysgenesis vs dyshormonogenesis), screening, and treatment.

  3. PMID:25729683 — Agrawal et al. (2015) "Congenital hypothyroidism" — Review covering epidemiology (85% dysgenesis, 15% dyshormonogenesis), clinical features, screening, treatment.

  4. PMID:41303336 — Dermitzaki et al. (2025) "Molecular Genetics of Primary Congenital Hypothyroidism: Established and Emerging Contributors to Thyroid Dysgenesis" — Review of 10 established TD genes (TSHR, PAX8, NKX2-1, NKX2-5, FOXE1, JAG1, NTN1, GLIS3, CDC8A, TUBB1).

  5. PMID:29650690 — Sun et al. (2018) "The genetic characteristics of congenital hypothyroidism in China" — NGS of 21 genes in 110 patients showing DUOX2 most frequently mutated; dyshormonogenesis predominant in Chinese population.

  6. PMID:37390946 — Zhang et al. (2023) "Clinical, biochemical characteristics and genotype-phenotype analysis" — DUOX2 highest variant rate, followed by TG, TPO, TSHR.

Key Facts

  • Incidence: 1:2000–1:3000 for primary CH; ~1:16,000 for central CH
  • Thyroid dysgenesis accounts for 65–85% of primary CH cases
  • Dyshormonogenesis accounts for 15–35% (higher in some populations)
  • Category: Complex (both genetic and environmental/iodine factors)
  • Newborn screening has nearly eliminated cretinism where implemented
  • Early levothyroxine treatment (within 2 weeks) is critical for neurodevelopment