Genetic analysis of de novo 17q terminal partial trisomy

Abstract

Abstract Background Chromosomal trisomy syndromes are associated with diverse clinical phenotypes, including intellectual disabilities. Partial trisomy of distal 17q is a rare anomaly with similar clinical features, including psychomotor and growth deficits, facial dysmorphism, and microcephaly. Here, we describe three patients from two unrelated families with terminal trisomy of 17q detected using chromosomal karyotype analysis and chromosomal microarray analysis. Results The child in Family 1 had a 31.3 Mb mosaic duplication on chromosome 17. Family 2 included dizygotic twins with a 263 kb deletion on chromosome 15 and 9.2 Mb duplication on chromosome 17, despite normal karyotyping results for both parents. We also analyzed the genetic mechanisms underlying the occurrence of this chromosomal aberration and summarized the literature describing known genotype–phenotype correlations. Conclusion Given the rarity of partial trisomy of terminal 17q, these cases provide new insights into the diagnosis of the condition and genotype–phenotype correlations, which can aid in detection and genetic counseling.