Objective: To develop a fetal muscle biopsy technique for immunohistochemical diagnosis of Duchenne and Becker muscular dystrophies.
Methods: Data from two clinical centers and one reference laboratory were combined to show 12 completed cases, ten at risk for Duchenne muscular dystrophy, one for Becker muscular dystrophy, and one for mitochondrial myopathy. Samples of fetal gluteal muscle were obtained percutaneously under ultrasound guidance (some with endoscopic assistance) with a biopsy gun. The samples were frozen and assayed for dystrophin by immunohistochemical techniques.
Results: Samples were obtained in 11 of 12 (92%) cases, and spontaneous abortion after the procedure occurred in two of 12 (17%) cases. Laboratory diagnoses were possible on small samples, and four of 12 fetuses (33%) were affected. Endoscopy with direct visualization might aid in the procedure.
Conclusions: The development of fetal muscle biopsy allows for an expansion of the diagnostic possibilities for myopathies. The experiences of our two clinical centers show that the procedure can be done with accuracy and acceptable safety. The evolving laboratory experience has reduced the amount of tissue necessary for the diagnosis, increased the sophistication of the immunohistochemical analysis, allowed the diagnosis of abnormalities in different parts of the dystrophin gene, and expanded the indications for the use of fetal muscle biopsy. Fetal muscle biopsy can be used successfully for the diagnosis in otherwise uninformative cases, and there is a wide variety of indications beyond traditional Duchenne muscular dystrophy possible, including female fetuses at risk because of X-autosomal translocations.