OBJECTIVES: to describe the clinical findings in three families from Pernambuco with autosomal recessive primary microcephaly, and the linkage analysis in one of them (family 2). METHODS: three consanguineous families from Pernambuco, not related one to another and with primary microcephaly, were studied. The genealogical data and the clinical history of the affected individuals were obtained from their parents and other family members. All the affected subjects, almost all their normal siblings, and their parents were clinically examined. Genomic DNA from the microcephalic persons of family 2 and from their parents was used in PCR (polimerase chain reaction) reactions with primers designed to amplify microsatellite markers linked to the known autosomal recessive primary microcephaly loci. Amplified markers were electrophoresed and analysed. RESULTS: in the three families, all the affected subjects presented a small head circumference with accompanying mental retardation, and only one patient (of family 3) showed other neurological problems. None of the microcephalic individuals had dysmorphic features. Molecular studies on family 2 revealed that the microcephaly in this family was not linked to any of the already known autosomal recessive primary microcephaly loci. CONCLUSION: at least one more locus associated with autosomal recessive primary microcephaly exists and awaits discovery.
Microcephaly; Linkage
