Muscle phosphoglycerate mutase deficiency revisited.
BACKGROUND
Phosphoglycerate mutase (PGAM) deficiency (glycogen storage disease type X) has been reported in 12 patients of whom 9 were African American.


OBJECTIVE
To describe 2 patients, 1 of Pakistani and 1 of Italian ethnic origin, with typical clinical and biochemical changes of glycogen storage disease type X and novel mutations in the gene encoding the muscle subunit of PGAM (PGAM2).


METHODS
Clinical, pathological, biochemical, and molecular analyses.


METHODS
Tertiary care university hospitals and academic institutions. Patients A 37-year-old Danish man of Pakistani origin who had exercise-related cramps and myoglobinuria and a 65-year-old Italian man who had exercise intolerance and myalgia but no pigmenturia and had undergone long-term statin therapy.


METHODS
Clinical course and biochemical and molecular features.


RESULTS
Biochemical evidence showed severe isolated PGAM deficiency, and molecular studies revealed 2 novel homozygous mutations, a nonsense mutation and a single nucleotide deletion. Pathological studies of muscle showed mild glycogen accumulation but prominent tubular aggregates in both patients.


CONCLUSIONS
We found that glycogen storage disease type X is not confined to the African American population, is often associated with sarcoplasmic reticulum (SR) proliferation, and is genetically heterogeneous.
Naini
Ali
A
Department of Neurology, Columbia University Medical Center, New York, New York, USA.
Toscano
Antonio
A
Musumeci
Olimpia
O
Vissing
John
J
Akman
Hasan O
HO
DiMauro
Salvatore
S
D000328:Adult; D000368:Aged; D003402:Creatine Kinase / Q000097:blood; D006008:Glycogen Storage Disease / Q000235:genetics* / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D007558:Italy; D008297:Male; D010154:Pakistan; D010736:Phosphoglycerate Mutase / Q000172:deficiency* / Q000235:genetics
D003402:Creatine Kinase; D010736:Phosphoglycerate Mutase