This case correponds to a six-year old child which presented a fragile site in the short arm of the chromosome 1 (region 2, band 2) during a routine cytogenetic study in peripheral blood. Blood culture was repeated in 199 and RPMI 1640 (with and without aphidicolin) media in order to corroborate the previous findings. A high frequency of fragile sites was observed in these cultures. The most relevant phenotypic signs were microcephaly, exophtalmia, macrostomia, abnormal tooth implantation, clinodactily and syndactyly of the second and third finger of left hand and foot, slight mental retardation and convulsions. According to the literature, the association of fra 1p22 with these clinical conditions has not been previously repoted