Different clinical aspects of debrancher deficiency myopathy

Abstract

Objective-To characterise the main clinical phenotypes of debrancher deficiency myopathy and to increase awareness for this probably underdiagnosed disorder. Methods-The diagnosis of debrancher deficiency was established by laboratory tests, EMG, and muscle and liver biopsy. Results-Four patients with debrancher deficiency myopathy were identified in the Tyrol, a federal state of Austria with half a million inhabitants. Clinical appearance was highly variable. The following phenotypes were diVerentiated: (1) adult onset distal myopathy; (2) subacute myopathy of the respiratory muscles; (3) severe generalised myopathy; and (4) minimal variant myopathy. Exercise intolerance was uncommon. The clinical course was complicated by advanced liver dysfunction in two patients and by severe cardiomyopathy in one. All had raised creatine kinase concentrations (263 to 810 U/l), myogenic and neurogenic features on EMG, and markedly decreased debrancher enzyme activities in muscle or liver biopsy specimens. The findings were substantiated by a review of 79 previously published cases with neuromuscular debrancher deficiency. Conclusions-This study illustrates the heterogeneity of neuromuscular manifestations in debrancher deficiency. Based on the clinical appearance, age at onset, and course of disease four phenotypes may be defined which diVer in prognosis, frequency of complications, and response to therapy. (J Neurol Neurosurg Psychiatry 1999;67:364-368)

Glikojen depo hastalığı tip III tanılı 10 Türk olgunun mutasyon analizleri: dört yeni mutasyonun tanımlanması

“…Similar to previous studies, no correlation was found between muscle involvement and CK levels (17,18). It is thought that CK levels should be measured again in the follow-up.…”

Glycogen Storage Disease Type III diagnosis and management guidelines

“…Despite the fact that muscle glycogen is crucial for normal muscle energy metabolism, dynamic symptoms of exercise intolerance are not recognized in GSD III. 49 Unlike GSD V and VII, and distal glycolytic defects, exertional muscle contractures or recurrent rhabdomyolysis are not features of this disorder. 49,58 The fact that similar symptoms have not been described in GSD IIIa suggests that glycogen branches accessible to myophosphorylase (enzyme deficient in GSD V) provide sufficient anaerobic glycogenolysis to be protective.…”

“…48 Although rarely performed in the clinical scenario of GSD III, forearm exercise testing will demonstrate a blunted increase in lactate in GSD III. 49 Uric acid levels could also be elevated in the setting of muscle exertion. 50 Hepatomegaly and/or myopathy often lead gastroenterologists and neurologists to biopsy the liver or muscle/nerve to differentiate among the diverse causative factors in the differential diagnosis.…”

“…Gross motor symptoms presenting in early childhood may improve or resolve somewhat with the potential for reemergence of proximal and distal weakness in adult, exacerbated by distal atrophy suggesting underlying neuropathy. 49 Musculoskeletal features may include hypermobility at individual joints, with hyperextension at knees and elbows, and alignment characterized by an anterior pelvic tilt and mild lumbar lordosis, slightly increased width of base of support, genu valgum and recurvatum, hindfoot valgus, and forefoot varus. Anterior pelvic tilt and increased width of base of support may be related to postures assumed to accommodate increased abdominal girth from hepatomegaly and may lead to biomechanical disadvantage in the use of abdominal muscles and hip extensors and abductors.…”

“…Individuals may have symmetrical, predominantly proximal or more generalized weakness, occasionally in association with hypertrophy/pseudohypertrophy of some muscles. 49,101 Another characteristic manifestation is distal weakness and atrophy suggesting underlying neuropathy. Although these cases may be termed distal myopathy, peripheral neuropathy due to debrancher deficiency may contribute to this pattern of weakness.…”