A new syndrome with mental retardation, short stature and an Xq duplication

Abstract

We describe a new X-linked syndrome of marked short stature, severe intellectual handicap and an unusual facial appearance. High resolution prometaphase banding showed affected males to have an X chromosome tandem duplication; their karyotypes were designated 46,dup(X) (q13.1-q21.1)Y. In carrier females the abnormal X chromosome was late replicating. To verify the duplication, gene dosage studies were performed using an enzyme assay and DNA techniques. Prenatal diagnosis is available for carrier females using chromosome analysis of amniocytes or chorionic villi.

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.…”

X inactivation phenotype in carriers of Pelizaeus-Merzbacher disease: skewed in carriers of a duplication and random in carriers of point mutations

“…DNAs from males were used as control for complete HpaII digestion. Products were analysed on an ABI 377 sequencer and the peak heights were analysed using Figure 1 The pattern of X inactivation, a duplication carriers and the deletion carrier (PMD25); b non-carrier relatives of duplication carriers; c affected females (PMD16, 18,19,20) and point mutation carriers PMD12,13,14); d normal female controls. The number in boxes refer to PMD family number.…”

“…17 This is also found in carriers of cytogenetically detectable deletions and duplications on the X chromosome. 18,19 The skewed X inactivation, in most cases, is a result of selection against cells with growth disadvantage. Carriers of PMD with a duplication have a submicroscopic chromosomal rearrangement which includes other coding sequences in addition to the PLP gene.…”

Xq26.2-q26.3 microduplication in two brothers with intellectual disabilities: clinical and molecular characterization

“…The prevalence of Xq duplications is still unknown, and only few have been reported. [6][7][8][9][10][11][12][13][14][15][16] To date, cryptic duplications encompassing MECP2 gene seem to be the most frequent microduplication syndrome responsible for cognitive impairment in patients with Xq distal duplications. Approximately 1% of unexplained XLMR may be caused by MECP2 duplications.…”