Two girls with a de novo Xq rearrangement of paternal origin: t(X;9)(q24;q12) or rea(X)dup q

Abstract

Our observations further document the cytogenetic heterogeneity and predominant paternal origin of certain de novo X-chromosome rearrangements.

An Unbalanced <em>de novo</em> t(X;12)(q28;q15) in a Disabled Girl. Review of 25 (X;12) Translocations

“…There were 10 de novo (both parents or at least the mother were tested and had normal chromosomes), 5 familial with maternal transmission, and 10 of untraced origin. Regarding the de novo subgroup, the paternal origin of the sole translocation properly tested (case 8) agrees with such a parental derivation documented in de novo X-chromosome translocations and other rearrangements [3,4,22]. Given the usual spermatogenesis arrest at meiosis I in X;Autosome translocation carriers [6,22], it appears that de novo exchanges of paternal origin arose at meiosis II.…”

“…Among constitutional X;Autosome translocations, those involving chromosome 12 are uncommon: just 5 such exchanges were listed in 2 overlapping compilations of >100 different t(X;A) cases published worldwide [1,2] and only 2 comparable exchanges were found among 62 distinct (X;A) translocations diagnosed in UK [3]. For comparison, there were 11 t(X;9) in such UK sample and 52 similar (X;9) exchanges recorded globally until 2016 [4]. Here, we report on a de novo unbalanced (X;12) translocation and compile 25 similar exchanges to summarize their relevant cytogenetic aspects.…”