IEMbase 0330: ALG9-related mannosyltransferase 7-9 deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 330 |
| Nosology | 18.1.12.01 |
| Gene | ALG9 |
| External IDs | OMIM:608776 |
| Generated mapping | MAPPED to ALG9-congenital_disorder_of_glycosylation.yaml |
| Candidate DisMech targets | ALG9-congenital_disorder_of_glycosylation.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents ALG9-CDG/CDG-IL as a type I congenital disorder of glycosylation. Characteristic rows include epilepsy, facial dysmorphism, hypotonia, skeletal dysplasia, and strabismus. Additional clinical rows include brain atrophy on MRI, broad thumbs, demyelination, depressed nasal bridge, failure to thrive, frontal bossing, hepatomegaly, hypertelorism, inverted nipples, inverted widely spaced nipples, large mouth, low-set ears, microcephaly, pericardial effusion, psychomotor delay, renal cysts, and splenomegaly.
The biochemical profile includes increased asialotransferrin and disialotransferrin, increased lipid-linked Man6GlcNAc2 and Man8GlcNAc2, type 1 sialotransferrin pattern, decreased tetrasialotransferrin, low-to-normal albumin and cholesterol, increased dolichol-linked Man6GlcNAc2 and Man8GlcNAc2, and low-to-normal factor XI. No treatment rows are present.
DisMech phenotype coverage
The generated mapping is correct. DisMech has a dedicated ALG9-CDG entry with ALG9/CDG-IL synonyms, biallelic ALG9 causation, type I transferrin hypoglycosylation, accumulated DolPP-GlcNAc2Man6 and DolPP-GlcNAc2Man8, developmental delay, hypotonia, seizures, microcephaly, intellectual disability, failure to thrive, hepatomegaly, renal cysts, pericardial effusion, abnormal heart morphology, hydrops fetalis, skeletal dysplasia, abnormal myelination, and generalized cerebral atrophy/hypoplasia.
DisMech is stronger for mechanism, evidence, prenatal skeletal-dysplasia context, and supportive seizure/cardiac surveillance. IEMbase adds compact feature prompts and confirms the Man6/Man8 lipid-linked biochemical signature.
Concordance and completeness
Judgement: correct high-concordance mapping.
The resources agree on the entity, gene, type I CDG mechanism, neurologic involvement, hypotonia, seizures, microcephaly, failure to thrive, hepatic, renal, cardiac, skeletal, demyelination/myelination, and Man6/Man8 biochemical signals. IEMbase adds review prompts for strabismus, broad thumbs, splenomegaly, cholesterol, albumin, and factor XI.
Curation actions
- Keep the generated ALG9-CDG mapping.
- Consider future enrichment with IEMbase-only dysmorphism, strabismus, splenomegaly, broad-thumb, albumin/cholesterol, and factor XI prompts after source verification.
- Treat absent IEMbase treatment rows as incomplete IEMbase coverage; local supportive seizure and cardiac-surveillance rows remain appropriate.