EMG and needle muscle biopsy studies in arthrogryposis multiplex congenita.

From 1979 to 1983, EMG and/or muscle biopsy studies were done in twenty-one of twenty-two patients seen in our institution for the first time for arthrogryposis multiplex congenita (AMC). Most of the muscle biopsies were done with a needle. As expected, the final diagnosis in these patients was very heterogeneous since it is well recognized that AMC can be due to any factor that interferes with fetal mobility. We found however a surprisingly high number of patients (9/22) affected by a myopathic disease. Based on these results, we feel that needle muscle biopsy should be included as a routine procedure in infants affected by AMC since by clarifying the diagnosis it helps in improving genetic counselling and prognosis in these patients. It is now widely accepted that arthrogryposis multiplex congenita (AMC) is not in itself a disease but is secondary to any factor that interferes with fetal movements. The joint deformities seen in these children can be due to mechanical factors (oligohydramnios for example), central or peripheral nervous system disorders, muscle diseases... (Dubowitz 1978, Hageman and Willemse 1983, Hall 1981, Swinyard 1982). However, the relative frequency of each etiologic factor remains unclear since in spite of the abundant literature on the subject, we found only three reports describing the findings of electromyographic (EMG) and muscle biopsy studies done systematically in unselected groups of children affected by AMC (Amick et al 1967, Bharucha et al 1972, Dastur et al 1972, Kullmann and Szijj 1973). Furthermore, each article reached different conclusions in regard to the occurrence of these various etiologies in their respective patients.(ABSTRACT TRUNCATED AT 250 WORDS)