Trisomy 5p and Miller-Dieker syndromes frequently are the result of unbalanced 
segregations of reciprocal translocations of chromosomes 5 and 17 with other 
autosomes. The critical regions for the expression of the mentioned syndromes 
have been mapped to 5p13-->pter, and 17p13.3-->pter. In this report, we describe 
an 8-year-old girl with mental retardation, postnatal growth deficiency, 
generalized muscular hypotonia, seizures, microcephaly, cortical atrophy, 
partial agenesis of corpus callosum, cerebral ventriculomegaly, facial 
anomalies, patent ductus arteriosus, pectus excavatum, long fingers, and 
bilateral talipes equinovarus caused by the presence of a 
46,XX,der(17)t(5;17)(p13.1;p13.3)mat chromosome complement. Cytogenetic studies 
of the family confirmed a balanced reciprocal translocation (5;17)(p13.1;p13.3) 
in her mother, maternal grandfather, maternal aunt, and a female first cousin. 
Fluorescence in situ hybridization studies on the mother and the proposita using 
three probes, which map to distal 17p, confirmed the reciprocal translocation in 
the mother and a terminal deletion in the patient, which resulted in the 
retention of LIS1 and D17S379 loci and deletion of the 17p telomere. These 
findings and the phenotype of the proposita, strongly suggest that genes 
telomeric to LIS1 and locus D17S379 are involved in many clinical findings, 
including the minor facial anomalies of the Miller-Dieker syndrome.