Partial 5p Gain and 15q Loss in Three Patients from a Family with a t(5;15)(p13.3;q26.3) Translocation

Several patients with 5p duplication or 15q deletion have been reported in the literature, involving different chromosome regions and clinical features. Here, we describe a family in which we identified a 30-Mb 5p15.33p13.3 gain and a 2.5-Mb 15q26.3 loss in 3 individuals, due to a balanced familial translocation between chromosomes 5p and 15q. They presented a similar combination of clinical findings related to their genetic imbalances, but there were also phenotypic differences between them. Our analyses show that their clinical picture is mostly caused by the loss in 15q and not the gain in 5p, despite its much larger size. Our findings suggest that other genes, besides the <i>IGF1R</i> gene, in the 15q26.3 region, such as the <i>CHSY1</i> gene, may have a great impact on the clinical picture of the syndrome. Our data emphasize the importance of detailed cytogenomic and clinical analyses for an accurate diagnosis, prognosis, and genetic counseling, providing an opportunity to improve genotype-phenotype correlations of patients with partial 5p duplication and 15q deletion syndromes.

Familial Translocation t(5;15)(p14.2;q26.2) Causing a Mirror Combination of Several Known Genetic Conditions

Two siblings with an unbalanced cytogenetic composition are described: a brother with partial trisomy 5p and distal 15q microdeletion, and a sister with partial monosomy 5p and distal 15q microduplication, resulting from a familial balanced translocation 46,XY; t(5;15)(p14.2;q26.2). To our best knowledge, there are no previous clinical and cytogenetic reports in the literature describing a family with concomitant presence of such a unique mirror combination. Clinical features of pure imbalances and the effects of their combination are discussed.