IEMbase 0332: MGAT2-related N-acetylglucosaminyltransferase 2 deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 332 |
| Nosology | 18.1.24.01 |
| Gene | MGAT2 |
| External IDs | OMIM:212066 |
| Generated mapping | UNMAPPED; low-score candidate MGAT2-congenital_disorder_of_glycosylation.yaml |
| Candidate DisMech targets | MGAT2-congenital_disorder_of_glycosylation.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents MGAT2-CDG/CDG-IIa, a type II congenital disorder of glycosylation. Characteristic rows include big open mouth, dysplastic ears, facial dysmorphism, hearing loss, hypotonia, kyphosis, male genital hypoplasia, and psychomotor delay. Additional clinical rows include absent puberty, beaked nose, bleeding tendency, cortical atrophy on MRI, decreased body height, delayed visual maturation, dental crowding, chronic diarrhea, drug reactions, intractable epilepsy, everted lower lip, long eyelashes, fatal evolution before 1 year, feeding difficulties, foot deformity, gastroesophageal reflux, gastrointestinal bleeding, gum hypertrophy, large ears, long philtrum, macrodontia, microcephaly, abnormal movement, muscular dystrophy, myopia, open mouth, osteoporosis, pectus excavatum, problematic lymphocyte growth, prominent nasal bridge, radius dislocation, recurrent infections, respiratory insufficiency from muscle weakness and diaphragm paralysis, retrognathia, scoliosis, short neck, teeth abnormalities, thick eyebrows, thin upper lip, thin vermilion border, ventricular septal defect, vertebral anomalies, and stomach volvulus.
The biochemical rows include increased ASAT, normal arylsulfatase A, type 2 sialotransferrin pattern, decreased haptoglobin and thyroxin-binding globulin, decreased antithrombin III, factor IX, factor XI, and immunoglobulin G. No treatment rows are present.
DisMech phenotype coverage
The generated UNMAPPED status is a false negative. The low-score MGAT2 candidate is the correct local target. DisMech has a dedicated MGAT2-CDG entry with biallelic MGAT2 causation, impaired complex N-glycan maturation, abnormal carbohydrate-deficient transferrin profile, severe developmental disability, hypotonia, epilepsy, immune dysfunction, nonimmune hydrops fetalis, arrhythmia, feeding difficulties, sensorineural hearing impairment, spinal curvature, respiratory insufficiency, recurrent infections, dysmorphic facial features, ventricular septal defect, reduced factor XI activity, cortical visual impairment, osteopenia, and gastroesophageal reflux.
DisMech is stronger for mechanism and treatment, including immunoglobulin replacement and trimethoprim-sulfamethoxazole prophylaxis. IEMbase is broader for detailed dysmorphology, dental/GI/skeletal findings, and additional coagulation and serum-protein rows.
Concordance and completeness
Judgement: false negative; resolve to the local MGAT2-CDG entry.
The resources agree on MGAT2/CDG-IIa identity, type II transferrin abnormality, neurodevelopmental disease, hypotonia, epilepsy, hearing/visual involvement, immune dysfunction, infections, respiratory insufficiency, scoliosis/kyphosis, VSD, osteopenia/osteoporosis, GERD, feeding problems, dysmorphism, and factor XI involvement. IEMbase adds factor IX, haptoglobin, TBG, GI bleeding, stomach volvulus, macrodontia/gum hypertrophy, radius dislocation, puberty, and diaphragm-paralysis prompts.
Curation actions
- Mark this as a mapping false negative and resolve to
MGAT2-congenital_disorder_of_glycosylation.yaml. - Consider future enrichment with IEMbase-only factor IX, haptoglobin, thyroxin-binding globulin, GI bleeding/volvulus, dental, radius, and puberty prompts after source verification.
- Treat absent IEMbase treatment rows as incomplete IEMbase coverage rather than a contradiction of local antimicrobial and immunoglobulin support.