Trisomy rescue by postzygotic unbalanced (X;14) translocation in a girl with dysmorphic features

Abstract

In this report we present the clinical features and molecular and cytogenetic findings in a female with partial trisomy 14q. Molecular and cytogenetic studies allowed us to determine that the extra 14q material (of paternal origin) was translocated postzygotically onto the maternal X chromosome. Consequently, only the derivative X chromosome was inactivated, although inactivation apparently did not spread over the entire chromosome 14q. This partial inactivation makes the present case unusual, giving rise to phenotypic features absent in other patients with partial trisomy 14q, typically restricted to the distal part of the chromosome.

Trisomy 14pter → q21: A case with associated ovarian germ cell tumor and review of the literature

“…A similar facial appearance is found in individuals with trisomy 14pter!q21, q22, and q23 [Miller et al, 1979]. The clinical features depend on not only the region of chromosome 14 involved, but also on any additional trisomic or monosomic segments [Tada et al, 1982;Orellana et al, 2001]. The more consistent clinical features of proximal trisomy 14 include psycho-motor retardation, seizures, low birthweight, short stature, short neck, microcephaly, small/sloping palpebral fissures, microphthalmia, hypo/hypertelorism, lowset ears, dysplastic ears, arched mouth (thin and downturned), wide mouth, cleft palate or alveolar ridge, micrognathia, prominent nose, broad flat nasal bridge, short/long philtrum, clubfeet, clinodactyly, camptodactyly, flexion contracture, rib anomalies, cardiac anomalies, cryptorchidism, irritability, feeding difficulties, and recurrent respiratory infections (Table I) [Pena et al, 1976;Simpson and Zellweger, 1977;Johnson et al, 1979;Miller et al, 1979;Fried et al, 1980;Smith et al, 1980;Tada et al, 1982].…”

Spread of X-chromosome inactivation into chromosome 15 is associated with Prader–Willi syndrome phenotype in a boy with a t(X;15)(p21.1;q11.2) translocation

“…The translocation onto the X chromosome may be post-zygotic, given the juxtaposition of the paternal 15q on the maternal X chromosome. Furthermore, the absence of mosaicism, as determined from the cytogenetic (BrdU staining) and molecular (HUMARA assay) studies, imply the possibility that the translocation occurred very early during development, probably during the Wrst post-zygotic divisions, as seen in a previous report (Orellana et al 2001).…”

“…Several cases with XCI spread to the translocated autosome have been reported (Orellana et al 2001;Sharp et al 2001;Solari et al 2001;Stankiewicz et al 2006). Among these cases, the majority have shown the spread of XCI in an autosome (e.g., chromosomes 10, 14, and 15) (Orellana et al 2001;Sharp et al 2001;Stankiewicz et al 2006).…”

“…Among these cases, the majority have shown the spread of XCI in an autosome (e.g., chromosomes 10, 14, and 15) (Orellana et al 2001;Sharp et al 2001;Stankiewicz et al 2006). However, a few cases have not shown such a spread (e.g., chromosomes 2 and 21) (Solari et al 2001).…”

Primary ovarian failure in a mentally retarded woman with a de novo unbalanced X;autosome translocation

“…The relatively mild phenotype of distal 5q trisomy in the present case is because the translocation involves the X chromosome, and the derivative X chromosome contains the X inactivation center. The effects of partial trisomy may be reduced by the skewed inactivation of the derivative X chromosome (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13).…”