PROTOCOL OUTLINE: Blood samples are obtained from affected individuals and their family members after genetic counseling. Genetic linkage analysis is performed on these blood samples. Unaffected individuals undergo x-rays and technetium bone scans to detect the presence of bone disease. Affected individuals undergo bone densitometry, MRI studies, thallium scans, ophthalmologic examination, electrocardiogram, echocardiogram, and skin biopsies.