Utility of Fetal Muscle Biopsy for Diagnosis of Nemaline Myopathy

OBJECTIVES: To report and discuss prenatal diagnosis of nemaline myopathy (NM) using fetal muscle biopsy. METHODS: A consanguineous couple, with a history of a child with a clinical diagnosis of NM but no molecular genetic confirmation, was referred for prenatal diagnosis in two subsequent pregnancies. Fetal muscle biopsy with ultrasound guidance was undertaken at 22 and 21 weeks, respectively. RESULTS: Immunohistochemical and ultrastructural analysis of the fetal muscle specimen from the first 'at-risk' pregnancy was consistent with a diagnosis of NM and that pregnancy was terminated. Analysis of the fetal muscle specimen from the subsequent pregnancy revealed no pathologic abnormality. The pregnancy continued, and the child is unaffected. CONCLUSION: This represents the first reported prenatal diagnosis of NM by fetal muscle biopsy. Pathologic changes characteristic of NM can be identified in mid-second trimester fetal muscle.