Tandem duplication dup(X)(q13q22) in a male proband inherited from the mother showing mosaicism of X-inactivation

Abstract

An aberrant X chromosome containing extra material in the long arm was observed in a psychomotoric retarded boy and his healthy, short-statured mother. The proband showed generalized muscular hypotony, growth retardation, and somatic anomalies including hypoplastic genitalia and cryptorchism. Chromosomal banding techniques suggested a tandem duplication of the segment Xq13 leads to Xq22. In the mother the vast majority of lymphocytes showed late replication of the aberrant X chromosome. Some of her cells, however, contained an apparently active aberrant X. Both the early- and late-replicating aberrant X exhibited late replication patterns very similar to those described for normal X chromosomes in lymphocytes. Asynchrony of DNA replication among the two segments Xq13 leads to Xq22 in the dup(X) was never observed. We consider that the clinical picture of the proband is caused by an excess of active X material.

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

“…Using molecular cytogenetics and high resolution techniques, the duplicated segment was designated in our case as Xq13.3→q21.2. Other duplicated segments reported in the literature were consistent with Xq13q22 [Steinbach et al, 1980;Cremers et al, 1987;Carrio et al, 1991] (3 cases), and 1 case in each of the following: Xq13q24 [Sparks et al, 1997], Xq21q24 [Schwartz et al, 1986], Xcentq13 [Muscatelli et al, 1992], Xq26.3qter in a case of recombinant X chromosome [Mohandas et al, 1987], and Xq12q22 [Schmidt et al, 1991].…”

Multiple congenital anomalies, brain hypomyelination, and ocular albinism in a female with dup(X)(pter→q24::q21.32→qter) and random X inactivation

“…Conversely, 8 duplications of Xq were reported in males, all of whom had severe mental retardation and congenital anomalies [Schmidt et al, 1991;Vejerslev et al, 1985;Steinbach et al, 1980;Cremers et al, 1987;Schwartz et al, 1986;Thode et al, 1988;Yokoyama et al, 1992;Leonard, 1987]. A distinct phenotype for males with dup(X)(q13.3→q21.2) has been reported, based on the common findings of mental retardation, hypotonia, feeding difficulties, hypoplastic genitalia, and an abnormal face with ptosis, epicanthal folds, and down-turned corners of the mouth, i.e., the ThodeLeonard syndrome [Thode et al, 1988].…”

“…Ten were phenotypically normal (except for short stature) and were ascertained through a malformed child or abortion. In all of them, the dup(Xq) was late replicating, as predicted from their normal phenotype [Mohandas et al, 1987;Leonard, 1987;Morichon-Delvallez et al, 1988;Yokoyama et al, 1992;Schmidt et al, 1991;Schwartz et al, 1986;Steinbach et al, 1980;Thode et al, 1988;Carrio' et al, 1991]. In the remaining 7 cases, mental retardation and multiple congenital anomalies were present [Kleczkowska et al, 1993;Aughton et al, 1993;Varella-Garcia et al, 1981;Van Dyke et al, 1983;Knuutila et al, 1984;Magenis et al, 1984;MorichonDelvallez et al, 1988].…”

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.…”