IEMbase 0321: PMM2-related phosphomannomutase 2 deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 321 |
| Nosology | 18.1.01.01 |
| Gene | PMM2 |
| External IDs | OMIM:601785; ORPHA:79318 |
| Generated mapping | UNMAPPED |
| Candidate DisMech targets | No valid local PMM2-CDG target |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents PMM2-CDG/CDG-Ia as an autosomal recessive congenital disorder of glycosylation. Characteristic rows include cerebellar hypoplasia, demyelination, epilepsy, inverted nipples, liver dysfunction, osteopenia, pigmentary retinopathy, psychomotor retardation, strabismus, and decreased tendon reflexes.
Additional clinical rows include almond-shaped eyes, anorexia nervosa, ascites, cardiomyopathy, cervical compressive myelopathy, cryptorchidism, diarrhea, dysmorphic features, dysostosis multiplex, dysplastic ears, failure to thrive, fetal hydrops, high-arched palate, female hypergonadotropic hypogonadism, hypotonia, joint contractures, large ears, long philtrum, long slender fingers, prominent forehead, jaw, and nose, proteinuria, renal cysts, renal enlargement, stroke-like episodes, abnormal subcutaneous fat distribution, thin upper lip, vertebral anomalies, and vomiting.
The biochemical rows are increased serum sialotransferrins and decreased serum albumin. The treatment row is acetazolamide.
DisMech phenotype coverage
No valid local PMM2-CDG target exists. Existing local CDG files cover other genes such as ALG12, ALG9, SLC35A2, COG7, VPS51, and MGAT2. Some of those files mention PMM2-CDG as a comparator or differential diagnosis, but those mentions are not disease coverage for PMM2 itself.
The current CDG entries share broad features such as developmental delay, hypotonia, seizures, growth failure, dysmorphism, renal involvement, and type I transferrin hypoglycosylation, but they are gene-specific targets and should not be used as canonical mappings for PMM2-CDG.
Concordance and completeness
Judgement: true local disease gap.
IEMbase provides a high-priority future-curation profile for a common CDG: multisystem neurologic, hepatic, retinal, skeletal, endocrine, renal, and coagulation-adjacent disease with sialotransferrin abnormalities and acetazolamide treatment for cerebellar syndrome.
Curation actions
- Add a standalone PMM2-CDG target before treating this record as mapped.
- Do not map PMM2-CDG to other gene-specific CDG entries based on shared glycosylation phenotype.
- Preserve acetazolamide as a treatment review prompt and serum sialotransferrins as the key biochemical signal.