Glutaric aciduria type 2, late onset type in Thai siblings with myopathy.
Reported here is a novel presentation of late onset glutaric aciduria type 2 in two Thai siblings. A 9-year-old boy presented with gradual onset of proximal muscle weakness for 6 weeks. The initial diagnosis was postviral myositis, and then polymyositis. Electromyography and nerve conduction velocity testing indicated a myopathic pattern. Muscle biopsy revealed excessive accumulation of fat. Acylcarnitine profiling led to the diagnosis of glutaric aciduria type 2. Immunoblot analysis of electron-transferring-flavoprotein and its dehydrogenase electron-transferring-flavoprotein dehydrogenase led to mutation analysis of the ETFDH gene, which revealed two different pathogenic mutations in both alleles and confirmed the diagnosis of glutaric aciduria type 2 caused by electron-transferring-flavoprotein dehydrogenase deficiency. The boy recovered completely after treatment. Later, his younger sibling became symptomatic; the same diagnosis was confirmed, and treatment was similarly effective. Acylcarnitine profiling was a crucial investigation in making this diagnosis in the presence of normal urine organic acid findings. Late onset glutaric aciduria type 2, a rare cause of muscle weakness in children, should be included in the differential diagnosis of myopathy.
Wasant
Pornswan
P
Division of Medical Genetics, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand. sipws@mahidol.ac.th
Kuptanon
Chulaluck
C
Vattanavicharn
Nithiwat
N
Liammongkolkul
Somporn
S
Ratanarak
Pisanu
P
Sangruchi
Tumtip
T
Yamaguchi
Seiji
S
D000483:Alleles; D015153:Blotting, Western; D002648:Child; D004252:DNA Mutational Analysis; D044927:Electron-Transferring Flavoproteins / Q000235:genetics*; D006801:Humans; D007506:Iron-Sulfur Proteins / Q000235:genetics*; D008297:Male; D054069:Multiple Acyl Coenzyme A Dehydrogenase Deficiency / Q000175:diagnosis / Q000235:genetics; D018908:Muscle Weakness / Q000175:diagnosis / Q000235:genetics*; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics*
D044927:Electron-Transferring Flavoproteins; D007506:Iron-Sulfur Proteins; D000587:Oxidoreductases Acting on CH-NH Group Donors; C023120:electron-transferring-flavoprotein dehydrogenase