IEMbase 0489: PYGM-related muscle glycogen phosphorylase deficiency
Scope
| Field | Value |
|---|---|
| IEMbase ID | 489 |
| Nosology | 3.4.08.01 |
| Gene | PYGM |
| External IDs | OMIM:232600; ORPHA:368 |
| Generated mapping | CANDIDATE; MEDIUM; Glycogen_Storage_Disease_Type_I.yaml |
| Candidate DisMech targets | Glycogen_Storage_Disease_Type_I.yaml |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents autosomal recessive PYGM-related muscle glycogen phosphorylase deficiency as glycogen storage disease type V / McArdle disease. Treatments are creatine and sucrose. Biochemical rows include elevated plasma creatine kinase, decreased muscle phosphorylase, decreased lactate rise in the forearm exercise test, increased muscle glycogen, normal ammonia rise in the forearm exercise test, increased plasma uric acid, and normal-to-increased urine myoglobin. Clinical rows include the second-wind phenomenon and taurodontism.
DisMech phenotype coverage
Glycogen_Storage_Disease_Type_I.yaml is not the correct target. The local GSD
I entry models glucose-6-phosphatase system deficiency due to G6PC1 or SLC37A4,
with hepatic/renal glucose-6-phosphate hydrolysis failure, fasting
hypoglycemia, lactic acidosis, hyperlipidemia, hyperuricemia, hepatomegaly, and
GSD Ia/GSD Ib subtypes. It does not model PYGM, muscle glycogen phosphorylase
deficiency, McArdle disease, exercise-test lactate failure, myoglobinuria, or
second wind.
Concordance and completeness
Judgement: false-positive candidate; true PYGM/McArdle disease local gap.
The generated candidate appears driven by shared "glycogen storage disease"
vocabulary rather than disease identity. IEMbase's source disease is a skeletal
muscle glycogenolysis disorder caused by PYGM deficiency, whereas the candidate
DisMech file is a hepatic/renal glucose-release disorder caused by G6PC1 or
SLC37A4. Glycogen_Storage_Disease_Type_VII.yaml is a closer myopathic
exercise-intolerance neighbor, but it is PFKM/Tarui disease and should not be
used as exact coverage either.
Curation actions
- Do not map this record to
Glycogen_Storage_Disease_Type_I.yaml. - Track PYGM-related McArdle disease / GSD V as a local curation gap.
- Preserve IEMbase prompts for muscle phosphorylase activity, exercise-test lactate/ammonia pattern, second wind, myoglobinuria, creatine, sucrose, and taurodontism for a future exact entry.