We have studied four members of a family in which five individuals of both sexes in three generations have mild weakness and muscle aching. Serum creatine kinase (CK) and/or aldolase were mildly to moderately elevated. Tubular aggregates were present in all patients in all fiber types. Type 1 fiber predominance and type 2 hypotrophy or atrophy was noted in three biopsies. Fiber splitting was prominent in two cases. Electron microscopic studies confirm that the tubular aggregates originate from muscle sarcoplasmic reticulum (SR). The presence of T tubules making contacts with some tubules inside the collection of tubular aggregates is suggestive of their derivation from terminal cisternae.
A 16-year-old girl, previously in good health, developed progressive generalized muscle weakness following her first parturition. The neck and proximal limb muscles were especially weak and painful. Carnitine (4-trimethylamino-3-hydroxybutyrate) was markedly decreased in muscle, plasma, and urine. Dietary carnitine supplementation, 2.0 gm daily, was followed by clinical improvement and decreased lipid droplets in muscle biopsy. Together with previously reported cases, 2 fatal, the patient's illness emphasizes the risk of pregnancy in women with carnitine deficiency.
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