Schindler Disease (alpha-N-acetylgalactosaminidase deficiency) — Disease Characteristics Research Report

Executive summary

Schindler disease is an ultra-rare, autosomal recessive lysosomal storage disorder caused by biallelic pathogenic variants in NAGA (alpha-N-acetylgalactosaminidase), leading to α‑NAGA enzymatic deficiency and abnormal lysosomal glycan degradation. The clinical spectrum is classically divided into type I (infantile neuroaxonal dystrophy), type II (adult-onset “Kanzaki disease”), and type III (intermediate), but curated evidence emphasizes marked variable expressivity and uncertain penetrance, including clinically unaffected individuals with biochemical deficiency. (wang1990schindlerdiseasethe pages 1-2, castro2019anewcase pages 1-3, groopman2024assessmentofgenes pages 8-11)

Recent authoritative curation (ClinGen, 2024) classifies the gene–disease relationship as Definitive (MONDO:0017779), while still noting that the clinical impact of α‑NAGA deficiency can be unclear (variable phenotype). (groopman2024assessmentofgenes pages 8-11)

A key mechanistic feature in Kanzaki disease is lysosomal accumulation of Tn‑antigen (GalNAcα1‑O‑Ser/Thr) that co-localizes with the lysosomal marker LAMP‑1 in patient fibroblasts, supporting lysosome-localized substrate storage. (sakuraba2004structuralandimmunocytochemical pages 3-5, sakuraba2004structuralandimmunocytochemical media f06dc2b6)

Target disease and classification

• Disease name: Schindler disease / alpha-N-acetylgalactosaminidase deficiency
• Category: Mendelian (lysosomal storage disorder; glycoproteinosis/oligosaccharidosis)
• MONDO ID: MONDO:0017779 (alpha-N-acetylgalactosaminidase deficiency) (groopman2024assessmentofgenes pages 8-11, OpenTargets Search: Schindler disease,Kanzaki disease-NAGA)

1. Disease information (definition, identifiers, synonyms)

Concise overview. Schindler disease is a lysosomal enzyme deficiency syndrome due to absent or markedly reduced α‑N‑acetylgalactosaminidase (α‑NAGA) activity, with tissue storage and urinary excretion of α‑GalNAc–containing glycopeptides/oligosaccharides; severe infantile cases manifest as neuroaxonal dystrophy. (wang1990schindlerdiseasethe pages 1-2)

Synonyms / alternative names. Schindler disease, Schindler/Kanzaki disease, α‑NAGA deficiency, alpha‑N‑acetylgalactosaminidase deficiency; type II is historically termed Kanzaki disease. (sakuraba2004structuralandimmunocytochemical pages 1-2, castro2019anewcase pages 1-3)

Subtype concept. The spectrum is commonly divided into: - Type I: infantile neuroaxonal dystrophy (severe neurodegeneration). (wang1990schindlerdiseasethe pages 1-2, castro2019anewcase pages 1-3) - Type II: adult-onset angiokeratoma/lymphoedema ± neuropathy (Kanzaki disease). (castro2019anewcase pages 1-3, castro2019anewcase pages 3-3) - Type III: intermediate. (castro2019anewcase pages 1-3)

Key identifiers available in retrieved evidence. - MONDO:0017779 (alpha-N-acetylgalactosaminidase deficiency); MONDO subtypes also appear in OpenTargets (type 1/2/3 MONDO terms). (OpenTargets Search: Schindler disease,Kanzaki disease-NAGA, groopman2024assessmentofgenes pages 8-11) - MIM identifiers are present in Tajima et al. 2009 for Schindler disease (MIM 609241) and Kanzaki disease (MIM 609242). (tajima2009useofa pages 6-7)

Identifiers not found in retrieved full text: OMIM entry pages, Orphanet IDs, ICD-10/ICD-11 codes, and MeSH IDs were not present in the retrieved evidence set and therefore cannot be asserted here.

Evidence provenance (individual vs aggregated). The clinical characterization in the retrieved evidence largely derives from case reports/series and early biochemical genetics studies (e.g., Wang 1990; Keulemans 1996; Castro 2019). (wang1990schindlerdiseasethe pages 1-2, keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2, castro2019anewcase pages 1-3) Aggregated/curated disease-level evidence is represented by the ClinGen 2024 clinical validity curation and OpenTargets disease–target mapping. (groopman2024assessmentofgenes pages 8-11, OpenTargets Search: Schindler disease,Kanzaki disease-NAGA)

Table: This table summarizes the disease and gene nomenclature for Schindler disease/alpha-N-acetylgalactosaminidase deficiency using only identifiers explicitly supported in the retrieved evidence. It is useful for harmonizing preferred names, synonyms, subtype MONDO terms, and evidence-backed notes on inheritance and ClinGen validity.

2. Etiology

Disease causal factors

• Genetic cause: biallelic pathogenic variants in NAGA, encoding the lysosomal hydrolase α‑N‑acetylgalactosaminidase. (wang1990schindlerdiseasethe pages 1-2, groopman2024assessmentofgenes pages 8-11)
• Inheritance: autosomal recessive demonstrated in the original molecular report by segregation in a consanguineous family and intermediate parental enzyme activity. (wang1990schindlerdiseasethe pages 1-2)

Primary abstract-supported statement (direct quote-like from excerpt content). The 1990 JCI report describes Schindler disease as an infantile neuroaxonal dystrophy “resulting from the deficient activity of the lysosomal hydrolase, aN-acetylgalactosaminidase” and inherited “as an autosomal recessive trait,” with the causal molecular lesion producing p.E325K. (wang1990schindlerdiseasethe pages 1-2)

Risk factors

• Genetic risk factors: biallelic pathogenic NAGA variants (examples: p.E325K; p.E193*; p.R329W; p.R329Q; p.S160C). (wang1990schindlerdiseasethe pages 1-2, sakuraba2004structuralandimmunocytochemical pages 3-5, keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2, castro2019anewcase pages 1-3)
• Consanguinity: reported in early severe infantile families (consanguineous parents). (wang1990schindlerdiseasethe pages 1-2, keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2)

Non-genetic risk/protective factors. No environmental or lifestyle risk factors were identified in the retrieved evidence; disease is primarily Mendelian.

Protective factors / modifiers

Strong evidence for specific genetic modifiers is not present in the retrieved full texts; however, multiple reports emphasize genotype–phenotype discordance (including severe vs mild presentations not explained by residual enzyme alone), implying modifiers beyond NAGA may contribute. (keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2, sakuraba2004structuralandimmunocytochemical pages 3-5, groopman2024assessmentofgenes pages 8-11)

Gene–environment interaction

No gene–environment interaction evidence was found in the retrieved set.

3. Phenotypes

The phenotype spectrum is dominated by neurologic disease in type I and dermatologic/neuropathy/systemic manifestations in type II, with substantial heterogeneity.

Type I (infantile)

Onset and progression. Affected infants “appeared normal for the first 9 to 12 mo,” then in “the second year of life” developed delay with rapid regression; by “3–4 yr of age,” severe neurologic phenotype including “cortical blindness” and “myoclonic seizures” is described. (wang1990schindlerdiseasethe pages 1-2)

Key clinical features (HPO suggestions). - Developmental regression; psychomotor regression; seizures (myoclonic/convulsions); spasticity; cortical blindness; hypotonia/areflexia/rigidity (as summarized in case literature); childhood death. (wang1990schindlerdiseasethe pages 1-2, castro2019anewcase pages 1-3, naumchik2020theroleof pages 7-9)

Type II (Kanzaki/adult-onset)

Core features. Angiokeratoma corporis diffusum, lymphoedema, peripheral neuropathy, sensorineural hearing loss, recurrent vertigo; carpal tunnel syndrome and possible cardiomegaly/septal hypertrophy have been reported. (castro2019anewcase pages 1-3, castro2019anewcase pages 3-3)

Example case (real-world clinical phenotype). A 68-year-old man with “axonal and demyelinating polyneuropathy… sensorineural hearing loss, chronic lymphoedema, angiokeratoma corporis diffusum and bilateral carpal tunnel syndrome” with NAGA c.577G>T (p.Glu193*) illustrates the adult presentation. (castro2019anewcase pages 1-3, castro2019anewcase pages 3-3)

Type III (intermediate)

The intermediate form is recognized, but detailed phenotypic characterization and frequencies were not present in the retrieved evidence set. (castro2019anewcase pages 1-3)

Phenotype frequencies and QoL measures. No robust frequency estimates, patient-reported outcomes, EQ‑5D/SF‑36/PROMIS metrics, or standardized QoL studies were found in the retrieved evidence.

Table: This table summarizes the phenotype spectrum of Schindler disease across type I, type II/Kanzaki, and type III presentations using only supported evidence snippets. It is useful for subtype-aware curation of onset, neurologic and systemic manifestations, biomarkers, and candidate HPO mappings.

4. Genetic / molecular information

Causal gene

• NAGA (alpha-N-acetylgalactosaminidase). (groopman2024assessmentofgenes pages 8-11, wang1990schindlerdiseasethe pages 1-2)

Pathogenic variants (examples from primary literature)

• c.973G>A (p.E325K) identified in the original severe infantile family; <1% residual enzyme activity in affected individuals. (wang1990schindlerdiseasethe pages 1-2)
• p.R329W / p.R329Q associated with Kanzaki disease; structural modeling suggests destabilization at the domain I–II interface. (sakuraba2004structuralandimmunocytochemical pages 3-5)
• c.577G>T (p.Glu193*) / p.E193X observed in adult/mild spectrum; described as a null mutation in Spanish patients; paradoxically can be associated with milder phenotype despite very low activity. (sakuraba2004structuralandimmunocytochemical pages 3-5, castro2019anewcase pages 1-3)
• p.S160C reported as an additional mutation in α‑NAGA deficiency. (keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2)

Functional consequences

Evidence supports loss of function via absent enzyme protein (CRIM-negative) and/or conformational destabilization, resulting in lysosomal substrate accumulation. (wang1990schindlerdiseasethe pages 1-2, sakuraba2004structuralandimmunocytochemical pages 3-5)

Population allele frequency

Population allele frequency data (gnomAD/ExAC/TOPMed) were not available in retrieved full texts and are not reported here.

Modifier genes / epigenetics / chromosomal abnormalities

No specific modifier genes, epigenetic findings, or chromosomal abnormalities were identified in retrieved evidence.

Table: This table summarizes key reported pathogenic NAGA variants in Schindler/Kanzaki disease, linking each to subtype associations, residual enzyme activity, and mechanistic interpretations. It is useful for quick curation of genotype-phenotype relationships and the notable variability in clinical expression.

5. Environmental information

No environmental, lifestyle, or infectious etiologic factors were identified in the retrieved evidence. Schindler disease is primarily a monogenic lysosomal disorder. (wang1990schindlerdiseasethe pages 1-2, groopman2024assessmentofgenes pages 8-11)

6. Mechanism / pathophysiology

Causal chain (current understanding)

1. Biallelic NAGA variants → deficiency of lysosomal α‑NAGA activity. (wang1990schindlerdiseasethe pages 1-2, groopman2024assessmentofgenes pages 8-11)
2. Impaired cleavage of terminal α‑N‑acetylgalactosamine residues on glycoconjugates → accumulation of undegraded glycopeptide substrates. (wang1990schindlerdiseasethe pages 1-2, sakuraba2004structuralandimmunocytochemical pages 5-7)
3. Lysosomal storage of substrates including Tn‑antigen (GalNAcα1‑O‑Ser/Thr) (especially evidenced for Kanzaki disease) → cellular vacuolization/storage pathology in multiple cell types. (sakuraba2004structuralandimmunocytochemical pages 3-5, sakuraba2004structuralandimmunocytochemical pages 5-7, keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2)
4. Tissue dysfunction: in severe infantile forms, neuronal/axonal pathology with spheroids/neuroaxonal dystrophy and rapid neurodegeneration; in adult forms, angiokeratoma/lymphatic and peripheral nerve involvement. (wang1990schindlerdiseasethe pages 1-2, castro2019anewcase pages 1-3, keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2)

Stored substrates and biomarkers

• Urinary biomarkers: increased excretion of glycopeptides/oligosaccharides containing α‑GalNAc moieties (glycopeptiduria); Keulemans reported “major abnormal urinary oligosaccharides” as O‑linked sialylglycopeptides with Ser/Thr-linked α‑GalNAc. (wang1990schindlerdiseasethe pages 1-2, keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2)
• Intracellular substrate (Kanzaki): Tn‑antigen accumulation in lysosomes of patient fibroblasts; Tn‑antigen fluorescence co-localizes with LAMP‑1. (sakuraba2004structuralandimmunocytochemical pages 3-5, sakuraba2004structuralandimmunocytochemical media f06dc2b6)

Cell types and tissues involved (examples from evidence)

• Dermal/vascular/lymphatic involvement: vacuolization in vascular and lymphatic endothelial cells, eccrine sweat gland cells, fibroblasts, dermal neural cells; glomerular endothelial involvement reported. (keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2)
• Nervous system: neuroaxonal dystrophy with terminal axonal spheroids in severe infantile disease. (wang1990schindlerdiseasethe pages 1-2)

Pathways and ontology suggestions

• GO (biological process): lysosomal catabolic process; glycoprotein catabolic process; oligosaccharide catabolic process; lysosome organization.
• GO (cellular component): lysosome.
• CL (cell types): endothelial cell; fibroblast; eccrine sweat gland cell; neuron; glial cell (suggested given CNS involvement).
• UBERON (anatomy): brain; peripheral nerve; skin; kidney glomerulus; heart.

(These ontology suggestions are consistent with the evidenced lysosomal storage process and the implicated tissues/cell types, though the specific ontology IDs were not enumerated in the retrieved full texts.)

7. Anatomical structures affected

Based on case and mechanistic evidence, major affected systems include: - Nervous system: CNS (infantile neurodegeneration; neuroaxonal dystrophy) and peripheral nervous system (polyneuropathy, carpal tunnel). (wang1990schindlerdiseasethe pages 1-2, castro2019anewcase pages 1-3) - Skin/vascular/lymphatic: angiokeratoma; lymphoedema; storage/vacuolization in dermal endothelial and eccrine structures. (castro2019anewcase pages 1-3, keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2) - Kidney (microvascular): glomerular endothelial cell vacuolization reported. (keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2) - Heart (possible): cardiomegaly or interventricular septal hypertrophy described in type II summary. (castro2019anewcase pages 1-3)

8. Temporal development

• Type I onset: normal infancy (9–12 months) followed by rapid regression beginning in the second year; severe neurologic phenotype by age 3–4. (wang1990schindlerdiseasethe pages 1-2)
• Type I course: progressive neurodegeneration; death in early childhood reported. (castro2019anewcase pages 1-3, naumchik2020theroleof pages 7-9)
• Type II onset: adult/late onset. (castro2019anewcase pages 1-3, keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2)

9. Inheritance and population

Inheritance

• Autosomal recessive, supported by segregation and enzyme activity in a consanguineous family in the original report. (wang1990schindlerdiseasethe pages 1-2)

Epidemiology

• Extremely rare: a 2004 review states that 12 patients from 8 families had been reported at that time. (sakuraba2004structuralandimmunocytochemical pages 1-2)
• A 2019 case report states “fewer than 20 cases” have been described. (castro2019anewcase pages 1-3)

Prevalence/incidence estimates, carrier frequency, and population-specific founder effects were not available in retrieved full text.

Penetrance/expressivity

ClinGen curation notes clinically unaffected family members who nonetheless share genotype and enzyme deficiency, indicating uncertain penetrance/expressivity for clinical disease, despite definitive gene–biochemical phenotype association. (groopman2024assessmentofgenes pages 8-11)

10. Diagnostics

Diagnostic workflow (current practice from retrieved evidence)

1. Clinical suspicion based on neurodegeneration (infantile) or angiokeratoma/lymphoedema/neuropathy (adult). (castro2019anewcase pages 1-3)
2. Biochemical testing: reduced α‑NAGA enzyme activity (blood and/or cultured cells) and urinary glycopeptiduria/abnormal urinary oligosaccharides. (castro2019anewcase pages 3-3, wang1990schindlerdiseasethe pages 1-2)
3. Confirmatory genetic testing of NAGA; the 2019 report describes PCR-based genetic testing as a “gold-standard.” (castro2019anewcase pages 3-3)

Recent developments (2023–2024 priority): MS-based urine assays for glycoproteinoses

A 2024 Clinical Chemistry study developed and validated a multiplexed UPLC‑MS/MS assay for urinary oligosaccharides and glycoamino acids (biomarkers of glycoproteinoses), selecting 28 oligosaccharides, 2 glycoamino acids, and 2 ratios, and reported: “In the 76 untreated patients, unambiguous diagnosis was achieved with 100% sensitivity and specificity.” (Apr 2024; https://doi.org/10.1093/clinchem/hvae043). Although Schindler disease was not explicitly singled out in the excerpted sections, it is part of the glycoproteinoses class for which urinary oligosaccharides/glycoamino acids are recognized biomarkers, making this assay paradigm relevant for implementation in biochemical genetics labs. (wongkittichote2024ultraperformanceliquidchromatography–tandem pages 1-2)

Differential diagnosis

The retrieved evidence notes biochemical overlap with Fabry testing due to related glycosidase biology and describes glycopeptiduria patterns; however, a structured differential diagnosis list was not available in retrieved text. (castro2019anewcase pages 1-3)

Screening

No disease-specific newborn screening approach for Schindler disease was identified in the retrieved full text. The 2024 MS paper discusses two-tier screening concepts for LSDs generally (e.g., DBS markers for some disorders), but Schindler-specific screening evidence was not present. (wongkittichote2024ultraperformanceliquidchromatography–tandem pages 8-10)

11. Outcome / prognosis

• Type I prognosis: the 2019 case review states type I “typically results in death before the age of 6 years.” (castro2019anewcase pages 1-3)
• Type II prognosis: variable; longer survival into adulthood is evident in the 68-year-old case report and other adult-onset descriptions. (castro2019anewcase pages 1-3)
• Blood group A: reported association with worse prognosis in the 2019 report (mechanistic rationale: A-antigen terminal residue normally cleaved by α‑NAGA). (castro2019anewcase pages 1-3)

No survival curves, standardized functional outcome statistics, or QoL metrics were identified in retrieved evidence.

12. Treatment

Current standard of care

The 2019 case report states there is no current disease-modifying therapy, and that “The only treatment… consists of support measures and symptomatic treatment.” (castro2019anewcase pages 1-3)

Supportive management (conceptual; MAXO suggestions). - Symptomatic neurologic management (e.g., seizure management) (MAXO: anticonvulsant therapy). - Support for hearing impairment (MAXO: hearing aid use). - Management of lymphedema (MAXO: compression therapy). - Neuropathy/carpal tunnel management (MAXO: peripheral nerve decompression; pain management).

(These MAXO mappings are suggested based on reported manifestations; no specific guideline-level evidence was retrieved.)

Proposed / experimental directions (authoritative expert reviews)

• The 2019 case report mentions “two pharmacological chaperones… have been proposed as potential therapeutic agents,” without naming compounds or providing trial evidence. (castro2019anewcase pages 1-3)
• Reviews of neurological LSD therapies emphasize BBB delivery constraints and emerging modalities such as BBB-targeted enzyme fusion strategies, AAV gene therapy, and hematopoietic stem cell gene therapy, with explicit limitations including myeloablation risk and delayed CNS effect. (ellison2023advancesintherapies pages 24-25, ellison2023advancesintherapies pages 14-15)

Hematopoietic cell transplant (HCT)

A 2020 review on HCT in glycoprotein diseases states that for Schindler disease, HCT “has not yet been pursued as a therapeutic option,” and lists no known cases; it explains the biologic rationale via cross-correction and potential CNS access compared with peripheral ERT. (naumchik2020theroleof pages 7-9, naumchik2020theroleof pages 9-11)

Clinical trials

No Schindler-specific interventional trials were retrieved. A relevant observational natural history effort for glycoproteinoses includes Schindler disease: - NCT01891422 (ClinicalTrials.gov; Greenwood Genetic Center; posted 2009): longitudinal study of glycoproteinoses aimed to define frequency, early features, progression, and evaluate supportive therapies; includes exams, neuropsychological testing, skeletal imaging, record review, and biospecimen banking. (NCT01891422 chunk 1)

13. Prevention

No primary prevention exists for a monogenic autosomal recessive condition. Prevention is primarily via genetic counseling (carrier testing, cascade testing in families, reproductive options). This is consistent with the autosomal recessive inheritance demonstrated in primary literature. (wang1990schindlerdiseasethe pages 1-2)

No population screening or newborn screening programs specific to Schindler disease were identified in retrieved evidence.

14. Other species / natural disease

The retrieved evidence set did not include naturally occurring veterinary Schindler disease. However, orthologous α‑NAGAL enzymes are described in other species as part of comparative enzymology.

15. Model organisms

C. elegans ortholog model

A 2005 study characterized gana‑1 (R07B7.11) as a single C. elegans ortholog of vertebrate α‑GAL and α‑NAGA, with measurable enzymatic activities and lysosome-compatible localization patterns; RNAi reduced activity without overt phenotype. (Jan 2005; https://doi.org/10.1186/1471-2121-6-5). (hujova2005characterizationofgana1 pages 1-2, hujova2005characterizationofgana1 pages 7-8)

Additional functional ortholog evidence

A 2022 PLOS Pathogens paper functionally characterized schistosome α‑NAGAL and explicitly situates human α‑NAGAL in the context of Schindler/Kanzaki disease, supporting evolutionary conservation of enzymatic function relevant to substrate cleavage. (hulme2022schistosomamansoniαnacetylgalactosaminidase pages 18-20)

ClinGen note on non-human models

ClinGen’s 2024 curation states that experimental evidence for NAGA includes biochemical function and “a non-human animal model,” contributing to the definitive classification, but does not specify the model organism in the excerpted text. (groopman2024assessmentofgenes pages 8-11)

Recent developments and authoritative expert analysis (2023–2024 prioritized)

1. ClinGen 2024 (Molecular Genetics and Metabolism, Nov 2024; doi:10.1016/j.ymgme.2024.108593): provides the most authoritative recent aggregation of genetic evidence, classifying NAGA–alpha-N-acetylgalactosaminidase deficiency as Definitive (9 probands; genetic evidence 8.85 points; total 11.85 rounded to 12), while emphasizing uncertain clinical penetrance/variable expressivity. (groopman2024assessmentofgenes pages 8-11)
2. Clinical Chemistry 2024 (Apr 2024; doi:10.1093/clinchem/hvae043): provides a validated, modern diagnostic implementation path via UPLC‑MS/MS urinary glycan profiling with high reported diagnostic performance (100% sensitivity/specificity in a subset). (wongkittichote2024ultraperformanceliquidchromatography–tandem pages 1-2)
3. J Inherit Metab Dis 2023 therapy review (May 2023; doi:10.1002/jimd.12615): synthesizes major LSD therapeutic trends (BBB-targeted enzyme delivery, AAV, HSC gene therapy) and explicitly quantifies general neurologic involvement (“greater than two-thirds of LSDs exhibit neuropathology”) and HSC-GT limitations (mortality risk, 3–4 week delay to CNS effect, insertional mutagenesis risk). (ellison2023advancesintherapies pages 2-3, ellison2023advancesintherapies pages 24-25)

Real-world implementations

• Clinical biochemical genetics diagnostics: enzyme activity assays and urine glycopeptide/oligosaccharide profiling remain core, with increasing adoption of LC/UPLC-MS/MS multiplex assays for glycoproteinoses and related LSDs in clinical laboratories. (castro2019anewcase pages 3-3, wongkittichote2024ultraperformanceliquidchromatography–tandem pages 1-2)
• Natural history data collection: NCT01891422 illustrates registry-style and biospecimen-banking implementations for glycoproteinoses, including Schindler disease, supporting future trial readiness. (NCT01891422 chunk 1)

Key evidence gaps (for knowledge-base completeness)

• Missing in retrieved full texts: Orphanet IDs, ICD-10/ICD-11 codes, MeSH IDs; population allele frequencies (gnomAD); systematic prevalence/incidence; validated Schindler-specific MS biomarker panels; standardized QoL measures; detailed type III phenotype.

Key visual evidence

• Sakuraba et al. (2004) immunocytochemistry figure shows Tn-antigen co-localization with LAMP-1 in Kanzaki fibroblasts, supporting lysosomal substrate storage. (sakuraba2004structuralandimmunocytochemical media f06dc2b6)

URLs and publication dates (from retrieved evidence)

• Wang AM et al. J Clin Invest. Nov 1990. https://doi.org/10.1172/jci114901 (wang1990schindlerdiseasethe pages 1-2)
• Keulemans J et al. J Med Genet. Jun 1996. https://doi.org/10.1136/jmg.33.6.458 (keulemans1996humanalphanacetylgalactosaminidase(alphanaga) pages 1-2)
• Sakuraba H et al. J Hum Genet. Jan 2004. https://doi.org/10.1007/s10038-003-0098-z (sakuraba2004structuralandimmunocytochemical pages 3-5, sakuraba2004structuralandimmunocytochemical media f06dc2b6)
• Tajima Y et al. Am J Hum Genet. Nov 2009. https://doi.org/10.1016/j.ajhg.2009.09.016 (tajima2009useofa pages 6-7)
• Naumchik BM et al. Cells. Jun 2020. https://doi.org/10.3390/cells9061411 (naumchik2020theroleof pages 7-9)
• Ellison S et al. J Inherit Metab Dis. May 2023. https://doi.org/10.1002/jimd.12615 (ellison2023advancesintherapies pages 2-3)
• Serrano TJ et al. J Clin Med. Mar 2024. https://doi.org/10.3390/jcm13051465 (serrano2024hepatomegalyandsplenomegaly pages 7-8)
• Wongkittichote P et al. Clinical Chemistry. Apr 2024. https://doi.org/10.1093/clinchem/hvae043 (wongkittichote2024ultraperformanceliquidchromatography–tandem pages 1-2)
• Groopman E et al. Mol Genet Metab. Nov 2024. https://doi.org/10.1016/j.ymgme.2024.108593 (groopman2024assessmentofgenes pages 8-11)
• ClinicalTrials.gov NCT01891422 (posted 2009; Greenwood Genetic Center). (NCT01891422 chunk 1)

Note on PMID requirements

The retrieved evidence snippets did not include PubMed IDs (PMIDs) explicitly. Where the user requested PMIDs, this report therefore provides DOI-based citations and tool-provided context IDs. PMIDs should be appended after independent PubMed lookup, which was not available in the current tool outputs.

References

1. (wang1990schindlerdiseasethe pages 1-2): Anne M. Wang, D. Schindler, and R. Desnick. Schindler disease: the molecular lesion in the alpha-n-acetylgalactosaminidase gene that causes an infantile neuroaxonal dystrophy. The Journal of clinical investigation, 86 5:1752-6, Nov 1990. URL: https://doi.org/10.1172/jci114901, doi:10.1172/jci114901. This article has 83 citations.

2. (castro2019anewcase pages 1-3): Rubén García Castro, Ana María González Pérez, María Concepción Román Curto, Javier Cañueto Álvarez, Alberto Conde Ferreirós, Alex Viñolas Cuadros, David Moyano Bueno, and Antonio Javier Chamorro Fernández. A new case of schindler disease. European Journal of Case Reports in Internal Medicine, 6:1, Oct 2019. URL: https://doi.org/10.12890/2019_001269, doi:10.12890/2019_001269. This article has 12 citations.

3. (groopman2024assessmentofgenes pages 8-11): Emily Groopman, Shruthi Mohan, Amber Waddell, Matheus Wilke, Raquel Fernandez, Meredith Weaver, Hongjie Chen, Hongbin Liu, Deeksha Bali, Heather Baudet, Lorne Clarke, Christina Hung, Rong Mao, Filippo Pinto e Vairo, Lemuel Racacho, Tatiana Yuzyuk, William J. Craigen, and Jennifer Goldstein. Assessment of genes involved in lysosomal diseases using the clingen clinical validity framework. Molecular Genetics and Metabolism, 143:108593, Nov 2024. URL: https://doi.org/10.1016/j.ymgme.2024.108593, doi:10.1016/j.ymgme.2024.108593. This article has 1 citations and is from a peer-reviewed journal.

4. (sakuraba2004structuralandimmunocytochemical pages 3-5): Hitoshi Sakuraba, Fumiko Matsuzawa, Sei-ichi Aikawa, Hirofumi Doi, Masaharu Kotani, Hiroshi Nakada, Tomoko Fukushige, and Tamotsu Kanzaki. Structural and immunocytochemical studies on α-n-acetylgalactosaminidase deficiency (schindler/kanzaki disease). Journal of Human Genetics, 49:1-8, Jan 2004. URL: https://doi.org/10.1007/s10038-003-0098-z, doi:10.1007/s10038-003-0098-z. This article has 60 citations and is from a peer-reviewed journal.

5. (sakuraba2004structuralandimmunocytochemical media f06dc2b6): Hitoshi Sakuraba, Fumiko Matsuzawa, Sei-ichi Aikawa, Hirofumi Doi, Masaharu Kotani, Hiroshi Nakada, Tomoko Fukushige, and Tamotsu Kanzaki. Structural and immunocytochemical studies on α-n-acetylgalactosaminidase deficiency (schindler/kanzaki disease). Journal of Human Genetics, 49:1-8, Jan 2004. URL: https://doi.org/10.1007/s10038-003-0098-z, doi:10.1007/s10038-003-0098-z. This article has 60 citations and is from a peer-reviewed journal.

6. (OpenTargets Search: Schindler disease,Kanzaki disease-NAGA): Open Targets Query (Schindler disease,Kanzaki disease-NAGA, 5 results). Buniello, A. et al. (2025). Open Targets Platform: facilitating therapeutic hypotheses building in drug discovery. Nucleic Acids Research.

7. (sakuraba2004structuralandimmunocytochemical pages 1-2): Hitoshi Sakuraba, Fumiko Matsuzawa, Sei-ichi Aikawa, Hirofumi Doi, Masaharu Kotani, Hiroshi Nakada, Tomoko Fukushige, and Tamotsu Kanzaki. Structural and immunocytochemical studies on α-n-acetylgalactosaminidase deficiency (schindler/kanzaki disease). Journal of Human Genetics, 49:1-8, Jan 2004. URL: https://doi.org/10.1007/s10038-003-0098-z, doi:10.1007/s10038-003-0098-z. This article has 60 citations and is from a peer-reviewed journal.

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