Partial trisomy 17q22-qter and partial monosomy Xq27-qter in a girl with a de novo unbalanced translocation due to a postzygotic error: Case report and review of the literature on partial trisomy 17qter

Abstract

Partial trisomy 17q22-qter is a rare but well-recognized clinical entity. We present a case of partial trisomy for the long arm of chromosome 17, which was detected in a female infant with severe psychomotor and somatic retardation, Stargardt disease, short limbs, and numerous minor anomalies. Differential chromosomal staining demonstrated an excess of genetic material on the long arm of the late replicating X chromosome. FISH and DNA polymorphism analysis showed that the extra material belonged to the distal part of the long arm of chromosome 17 and that there was a partial monosomy of the distal part of the long arm of the derivative X chromosome. The breakpoint regions of this translocation were identified by molecular analysis using polymorphic microsatellite markers on human chromosomes 17 and X. The origin of the abnormal X chromosome was found to be paternal, whereas the origin of the duplicated part of chromosome 17 was maternal. The unbalanced translocation between the paternal X and the maternal chromosome 17 is, therefore, suggested to be due to a postzygotic error.

Origin of nondisjunction in trisomy 8 and trisomy 8 mosaicism

“…The etiology of trisomy 8 therefore seems to differ from that of common autosomal trisomies, even when considering only liveborn mosaic cases, 13,14 and represents a new addition to the expanding category of mitotically derived chromosome abnormalities, as previously described in some cases of homologous Robertsonian translocations and isochromosomes 40,41 and unbalanced de novo translocations. 42,43 An excess of males was observed in the present study (19M:7F) as previously reported from clinical series. 16,20 Looking only at the mitotic cases in our study, the skewed sex ratio persists (15M:5F).…”

Trps1 and Its Target Gene Sox9 Regulate Epithelial Proliferation in the Developing Hair Follicle and Are Associated with Hypertrichosis

“…Hypertrichosis had previously been reported in a case of partial trisomy 17q22-qter associated with a de novo unbalanced translocation [14], suggesting that the distal portion of human chromosome 17q may contain dosage-sensitive genes that contribute to excessive hair growth. Recently, a series of microdeletions were reported on chromosome 17q24.2–q24.3 in three cases of familial congenital generalized hypertrichosis terminalis with gingival hyperplasia (CGHT), as well as a de novo microduplication within this same region in a case of sporadic CGHT [15].…”

Prenatal Diagnosis of a De Novo Partial Trisomy 17q Case Associated with Increased Nuchal Translucency, Hypoplastic Left Heart Syndrome, Cerebral Anomalies: Case Report

“…Partial trisomy 17q releated to recognizable dysmorphic evidences and psychomotor retardation. 6 Mental and growth retardation, microcephaly, high forehead, frontal bossing, temporal retraction, short and broad nose, broad and flat nasal bridge, large mouth with down-turned corners, thin upper lip, cleft palate, low-set and malformed ears, short and webbed neck, limb shortness and skeletal anomalies, abnormalities of genital, brain, heart and kidney were reported in partial trisomy17q patients. 6,7 Cordier et al first reported a combination of partial trisomy 17q and monosomy 5p in fetus.…”

“…Until now, 32 cases of partial trisomy for the distal region of 17q were reported either inherited or de novo. [2][3][4][5][6][7][8] A derivative chromosome 4 due to partial trisomy of chromosome 17q has never been described, to our knowledge. We demonstrated that the fetus was a carrier of a de novo derivative chromosome 4 arising from partial trisomy 17q.…”