Abstract
BackgroundThe 17p11.2p12 locus is an unstable region that is predisposed to several known genomic disorders and non-recurrent rearrangements that yield varied and wide-ranging phenotypes. Nearly 1% of male newborns have deletions in the Y chromosome; these events primarily involve the heterochromatic region, but may extend to euchromatic Yq segments containing azoospermia factor regions.Case presentationWe describe the occurrence of two independent chromosomal rearrangements that originated as de novo events in a single male patient: a 10.8-Mb duplication of 17p11.2p12 and a 14.7-Mb deletion of Yq11. This individual shares some clinical characteristics with previously described patients having one or the other of these rearrangements, including global developmental delay, short stature, hypotonia, delayed puberty, certain facial features and a generalized demyelinating sensory-motor polyneuropathy without clinical manifestation. Our patient also presents some features that were not previously described in relevant individuals, including camptodactyly, preauricular pits and hypertrichosis of the back and elbows.ConclusionsTo our knowledge, this is the first patient to be reported with independent de novo deletion/duplication events involving chromosomes 17 and Y. We discuss possible responsible mechanisms and address the phenotype, particularly in light of the clinical features that were not previously reported for patients bearing a duplication of 17p11.2p12 or a deletion of Yq11. We suggest that some of the previously reported patients with Yq11 deletion and clinical manifestations other than male infertility may have additional chromosomal imbalances that could be identified by chromosome microarray analysis, as illustrated by the present case.
Highlights
The 17p11.2p12 locus is an unstable region that is predisposed to several known genomic disorders and non-recurrent rearrangements that yield varied and wide-ranging phenotypes
The 17p11.2p12 locus is an unstable region characterized by the presence of low-copy repeats (LCRs) that predispose the region to acquire several genomic disorders generated by non-allelic homologous recombination
* Correspondence: ariadnagonzalezdelangel@gmail.com †Liliana Fernández-Hernández and María José Navarro-Cobos contributed to this work. 1Laboratorio de Biología Molecular, Departamento de Genética Humana, Instituto Nacional de Pediatría, Ciudad de México, México 3Centro de Alta Especialidad en Genética Humana, DNA GEN, S.C, Ciudad de México, México Full list of author information is available at the end of the article (NAHR) [1]. These recurrent genomic rearrangements include: the deletions that cause Smith-Magenis Syndrome (SMS, 17p11.2, ~ 3.6 Mb, MIM #182290); the duplications related to Charcot-Marie-Tooth Syndrome type 1A (CMT1A, ~ 1.4 Mb, MIM #118220), which is caused by triple gene-dosage for the PMP22 gene (17p12, MIM *601097) [1–3]; and Potocki–Lupski syndrome (PTLS, ~ 3.6 Mb, MIM #610883)
Summary
The 17p11.2p12 locus is an unstable region that is predisposed to several known genomic disorders and non-recurrent rearrangements that yield varied and wide-ranging phenotypes. The 17p11.2p12 locus is an unstable region characterized by the presence of low-copy repeats (LCRs) that predispose the region to acquire several genomic disorders generated by non-allelic homologous recombination (NAHR) [1]. These recurrent genomic rearrangements include: the deletions that cause Smith-Magenis Syndrome (SMS, 17p11.2, ~ 3.6 Mb, MIM #182290); the duplications related to Charcot-Marie-Tooth Syndrome type 1A (CMT1A, ~ 1.4 Mb, MIM #118220), which is caused by triple gene-dosage for the PMP22 gene (17p12, MIM *601097) [1–3]; and Potocki–Lupski syndrome (PTLS, ~ 3.6 Mb, MIM #610883). It has been estimated that structural abnormalities of the Y chromosome affect nearly of 1% of the newborn male population [6]; most involve duplication or deletion of Yq heterochromatin [7], and some could be considered normal variants [8]
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