Effect of chromosome constitution variations on the expression of Turner phenotype

Abstract

ABSTRACT. Turner syndrome (TS) is a chronic disease related to haploinsufficiency of genes that are normally expressed in both X chromosomes in patients with female phenotype that is associated with a wide range of somatic malformations. We made detailed cytogenetic and clinical analysis of 65 patients with TS from the region of Recife, Brazil, to determine the effects of different chromosome constitutions on expression of the TS phenotype. Overall, patients with X-monosomy exhibited a tendency to have more severe phenotypes with higher morbidity, showing its importance in TS prognosis. Additionally, we found rare genetic and phenotypic abnormalities associated with this syndrome. To the best of our knowledge, this is the first case of 45,X,t(11;12)(q22;q22) described as a TS karyotype. Turner patients usually have normal intelligence; however, moderate to severe levels of mental retardation were found in 5 TS cases, which is considerate a very uncommon feature in this syndrome.

Recognition and management of adults with Turner syndrome: From the transition of adolescence through the senior years

“…Women with Turner syndrome often demonstrate overall intellectual functioning within age‐based expectations, with only 5–10% in the range of intellectual disability (Bender, Linden, & Robinson, ; Bispo et al, ), often associated with mosaicism for a ring X chromosome (Kubota et al, ; Swillen et al, ). However, overall measures of intellectual functioning may not accurately predict global functioning given the variability in the neuropsychological profiles of women with Turner syndrome (reviewed in Knickmeyer & Hooper, ).…”

Prevalence and Physical Distribution of SRY in the Gonads of a Woman with Turner Syndrome: Phenotypic Presentation, Tubal Formation, and Malignancy Risk

“…It is important to accurately identify the precise Turner karyotype as it correlates with the severity of the Turner phenotype and specific sequelae [2]. For example, haploinsufficiency of genes on the long arm of the X chromosome is associated with gonadal dysgenesis, while patients with a deletion of the short arm usually have normal ovarian function [16].…”

“…The clinical features are highly variable and can be confirmed by chromosome analysis, which usually demonstrates complete or mosaic monosomy of the X chromosome. Although haploinsufficiency due to monosomy X is the most common karyotype found in Turner syndrome (50–60%), other structural abnormalities in the X chromosome, such as ring chromosomes, isochromosomes of the long arm, and deletion of the short arm have been reported [2] [3]. Additionally, there have been reports of a Y cell line in about 10% of patients [4], as well as complex karyotypes with derivative X chromosome material [2].…”

Clinical developmental, neuropsychological, and social–emotional features of Turner syndrome

“…These overall full-scale scores, however, obscure the pattern found across most studies, in which girls with TS reliably perform better on verbal than nonverbal tasks, often with one or more standard deviations of difference between their verbal and nonverbal scores (J. F. Rovet, 1990). There is also a subgroup of individuals with TS with more significant cognitive involvement, and it is estimated that about 5-10 percent have overall cognitive skills in the intellectual disability range (Bender, Linden, & Robinson, 1994;Bispo et al, 2013;Swillen et al, 1993).…”