Two cases with partial trisomy 9p: molecular cytogenetic characterization and clinical follow-up.

ABSTRACT

This paper describes two patients with partial trisomy 9p and partial trisomy 14q due to 31 segregation from de novo maternal reciprocal translocations. The breakpoints are different from previously described 9;14 translocations and their 31 segregation products. The clinical phenotype of both cases is compatible with the partial trisomy 9p syndrome. We present the follow-up of both patients from birth up to age 7 years. Partial trisomy 9p is a frequently described chromosome abnormality. This does not appear to be related to a breakage sensitive locus on chromosome 9p, since the trisomic fragments of the published cases are heterogeneous. In the two cases described here, GTG-banded karyotyping suggested that the 9p breakpoints were similar; DNA marker analysis, however, showed them to be different. Such DNA studies will be necessary to define the genotype-phenotype relation in partial trisomy 9p syndrome.