Inherited inverted duplication of X chromosome in a male: Report of a patient and review of the literature

Abstract

Nineteen cases of duplication of segments of the long arm of chromosome X have been published in 13 males and in 6 females. We report an additional case of a male with growth and mental retardation, growth hormone deficiency, compensated primary hypothyroidism, distinctive anomalies of the face, hypoplastic genitalia, and hypotonia in whom inverted duplication of a segment in the long arm of X chromosome was diagnosed, 46,Y, dup (X)(q21.2q13.3), and mosaicism was demonstrated in his mother's X chromosome. The rearranged segment was diagnosed utilizing high resolution G-band technique and FISH studies, using chromosome X total chromosome probe and DNA XIST probe. This appears to be the first report of a patient with duplication of Xq and hypothyroidism.

Familial interstitial Xq27.3q28 duplication encompassing the FMR1 gene but not the MECP2 gene causes a new syndromic mental retardation condition

“…[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] Yet, interstitial duplication encompassing the Xq27.3-Xq28 region has been reported in only three patients. 35,36 The probands were males and duplication was detected using routine cytogenetic analysis.…”

Subterminal deletion/duplication event in an affected male due to maternal X chromosome pericentric inversion

“…These both result in terminal duplication of the Xq region and terminal deletion of the Xp region. Duplications of the long arm of the X chromosome are also quite rare, with about 20 reported cases, all of whom have a severe phenotypic outcome [1,9,12,16,17,18,22]. Duplications of the terminal regions of the Xq chromosome have common phenotypic features, such as growth retardation of prenatal onset, developmental delay, hypotonia and cryptorchidism/retractile testes [1].…”

The genomic structure and developmental expression patterns of the human OPA-containing gene (HOPA)

“…This hypothesis is further strengthened by two reports of X-linked hypothyroidism associated with chromosomal rearrangement of the Xq13 region (Aller et al 1995;Shapira et al, 1997). However, before the significance of these preliminary haplotype conservation findings can be fully assessed, a good estimate of the number of founder X-chromosomes in the Finnish population will have to be derived, and the exact limits of the putative region of conservation of haplotype exactly defined.…”