OBJECTIVE: To describe the clinical, morphologic, and genetic findings in a 
family in which one woman had nemaline myopathy, whereas her daughter showed 
features of cap disease.
PATIENTS: A 66-year-old woman and her 35-year-old daughter had congenital, 
slowly progressive muscle weakness. They had weakness in both proximal and 
distal muscles and facial diplegia with bilateral ptosis, a long narrow face, a 
high arched palate, and micrognathia.
RESULTS: Muscle biopsy specimens in the mother at age 57 years had shown 
nemaline myopathy, whereas a biopsy specimen at age 32 years had demonstrated no 
rods. Muscle biopsy specimens in the daughter at age 26 years had shown features 
of cap disease and no apparent nemaline rods. A missense mutation, Glu41Lys, in 
the beta-tropomyosin gene TPM2 was identified in both patients but was absent in 
their healthy relatives.
CONCLUSIONS: The results indicate that mutations in TPM2 may cause nemaline 
myopathy as well as cap disease with a dominant mode of inheritance. These 
disorders may thus be phenotypic variants of the same genetic defect.