MOLECULAR DIAGNOSTIC STUDIES:
The methylation specific polymerase chain reaction (M-PCR) analysis was performed on genomic DNA from the patient using primers specific for the methylated and unmethylated versions of the SNRPN gene on chromosome 15q11-q13. The results showed the presence of both the 174 bp maternal band (methylated SNRPN gene) and the 100 bp paternal band (unmethylated SNRPN gene), indicating normal biparental
DNA sequence analysis of UBE3A gene:
DNA sequence analysis of the UBE3A gene was performed on the patient as well as his parents. All 10 coding exons of the UBE3A gene were PCR amplified and cycle sequenced in forward and reverse directions from genomic DNA isolated from the blood samples. A 1507del6 variant was detected in exon 9 of the UBE3A gene in the patient. This 6 bp deletion results in the deletion of two amino acids, lysine and valine, at positions 503 and 504 of the protein. The deletion occurs in a functionally important and highly conserved region of the UBE3A gene and is likely to affect its normal function. This sequence variation has not been reported previously.