PARENTAL ORIGIN EFFECTS IN HUMAN TRISOMY FOR CHROMOSOME 14Q - IMPLICATIONS FOR GENOMIC IMPRINTING

Parental origin specific congenital anomalies have been noted in patie nts with uniparental disomy of the long arm of human chromosome 14 (UP D14). This suggests the presence of imprinted genes, consistent with o bservations of imprinting in the region of syntenic homology in the mo use. It is not known whether the distinct defects reported for paterna l and maternal UPD 14 are the result of biallelic expression or absenc e of expression of imprinted genes. Furthermore, identification of the genes responsible would be facilitated by a higher resolution map of the imprinted region(s) involved. Subjects with partial trisomy for ch romosome 14 (Ts14) have been reported and hence also have an alteratio n in the dosage of their parental chromosomes. In this study, we have carried out genotype-phenotype correlations considering the parental o rigin of the extra chromosome in previously reported cases of maternal and paternal partial Ts14, The analysis has provided evidence of a co rrelation between distal maternal Ts14 and anomalies including low bir th weight, short philtrum, and small hands. The clinical features foun d in the maternal and paternal trisomies are compared with those assoc iated with maternal and paternal UPDl4 and their significance is discu ssed in relation to genomic imprinting on chromosome 14.