Figure 1

Histological findings in two brothers with severe NM. Gomori trichrome staining (A) through (D) of frozen muscle tissue reveals punctate red inclusions (nemaline rods) within the cytoplasm of skeletal muscle fibers. These structures are readily identifiable in a biopsy specimen from the rectus femoris muscle of patient 16-2 (A), an autopsy specimen of the psoas muscle from patient 16-2 (B) and autopsy specimens from the diaphragm (C) and abdominal wall (D) muscles of patient 16-4. Toluidine blue staining of Epon-embedded quadriceps muscle from patient 16-2 (E) reveals a diffuse distribution of nemaline rods and marked variation in myofiber size. Note the variation in nemaline rod burden, fiber size variation and fibrosis between individual muscles within the same patient. Ultrastructural examination of this tissue (F) confirms the identity of the dense cytoplasmic inclusions as nemaline rods. Scale bars = 200 μm for (A) through (E) and 40 μm for (F). NM, nemaline myopathy.