DEFINITION OF THE BLEPHAROPHIMOSIS, PTOSIS, EPICANTHUS INVERSUS SYNDROME CRITICAL REGION AT CHROMOSOME 3Q23 BASED ON THE ANALYSIS OF CHROMOSOMAL-ANOMALIES

Blepharophimosis syndrome (BPES) is an autosomal dominant disorder of craniofacial development, the features of which are small palpebral fi ssures (blepharophimosis), drooping eyelids (ptosis) and a skin fold a rising from the lower eyelid (epicanthus inversus), The chromosomal lo calization and identity of the BPES locus is not known with certainty, In the current paper, DNA samples from three individuals with a clini cal history of BPES, two with interstitial deletions (cases 1 and 2) a nd one with a balanced translocation (case 3) all involving chromosome 3q23, were analyzed, Allele loss studies using short tandem repeat ma rkers in cases 1 and 2 suggested that the region between the markers D 3S1292 and D3S1306 was deleted in both cases, Subsequently, the derive d chromosomes resulting from the translocation in case 3 were segregat ed in interspecific somatic cell hybrids, Analysis of the resultant hy brids showed that D3S1615 was retained in the derived chromosome 3, wh ereas D3S1316 was retained in the derived chromosome 4. In neither cas e was the marker present in the reciprocal hybrid, These results indic ate that the BPES critical region lies in the D3S1615-D3S1316 interval .