Patient M. L., a white boy, was born in 1962, from a possibly consanguineous union of a 14-year-old primigravida and a 38year-old man. Family history was unavailable. Birth weight, length, and head circumference were compatible with 36, 38, and 321/2 gesiational ~veeks, respectively. Multiple anomalies included short stature, microcephaly, developmental delay, bilateral ocular ptosis, hypoplastic and simplified left pinna with atresia of external auditory canal and hypoplasia of the mastoid bone, micrognathia, hypoplastic testes, hyperpigmentation, cafrau-lait spots, bilateral absence of radii and thumbs, bowed and shortened ulnae, and hypoplastic carpal bones. Urologic studies, done because of ear defects, showed small, dysplastic, and low-set kidneys, with a right pelvic kidney. At age 8 years, polytomograms of petrous ridges confirmed the absence of left external auditory canal and identified normal middle ear bones, round and oval windows, cochlea, and internal auditory canals. Audiogram at age 11 years showed a moderately severe loss of acuity on the left, mostly conductive, with nearly normal bone conduction. Complete blood counts during multiple hospitalizations to correct birth defects were normal until age 5 years, when a platelet count was 50,000/mm 3Following severe bleeding after dental extraction at age 81A years, the diagnosis of Fanconi