Postnatal outcomes of prenatally diagnosed 45,X/46,XX

Abstract

High quality information is critical for informed decision-making in pregnancy following a prenatal diagnosis of sex chromosome aneuploidy. The goal of this study was to define the spectrum of outcomes in patients with prenatally diagnosed 45,X/46,XX mosaic Turner syndrome in order to provide a better basis for genetic counseling at the time of intrauterine diagnosis. Phenotype data for twenty-five patients with prenatally diagnosed 45,X/46,XX mosaicism were collected by retrospective chart review and, when possible, semi-structured telephone interview. Existing data from a cohort of 58 patients with postnatally diagnosed 45,X/46,XX mosaicism were used for comparison. Relative to those diagnosed postnatally, prenatal patients were more likely to have normal growth and normal secondary sexual development, less likely to manifest distinctive Turner syndrome features such as nuchal webbing and edema, and had significantly fewer renal defects. These differences underscore the need for a nuanced approach to prenatal counseling in cases of 45,X/46,XX mosaicism.

Measured parental height in Turner syndrome—a valuable but underused diagnostic tool

“…2 ) which shows that growth velocity is typically low-normal for the first 3–4 years, with height falling away from the 3rd centile thereafter. Individuals with 45,X/46,XX genotype are known to be more mildly affected [ 17 ] as are those with the 45,X/47,XXX genotype [ 1 ] so that these girls will tend to be within the upper half of the Turner-specific charts and indeed may remain within the normal population range. We advise monitoring growth in girls with Turner syndrome using both condition-specific and population-based growth charts.…”

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

“…The number and severity of Turner syndrome features are generally correlated with the percentage of cells that have a single X chromosome (El‐Mansoury et al, ). Mosaicism with a 45,X/46,XX or 45,X/47,XXX karyotype is associated with milder cardiovascular phenotypes, including less prevalent and less severe congenital heart defects (CHD) and lymphatic abnormalities compared with non‐mosaic Turner syndrome (Cameron‐Pimblett et al, ; Klásková et al, ; Tokita & Sybert, ). Many features, including lymphedema, diabetes (both type 1 and type 2, T1D and T2D, respectively), neuropsychiatric traits, and left‐sided heart lesions, are more specifically associated with having a single copy of Xp (Bakalov, Cheng, Zhou, & Bondy, ; Bondy et al, ; Zinn et al, ).…”

Cognitive, behavioral, and neural consequences of sex chromosome aneuploidy

“…The causes for this difference are likely to be multiple and are likely to be influenced by SES, parental genetic background, and ascertainment bias, but few aneuploidy studies have systematically compared IQ scores and their relationship to age of diagnosis. Cases of XYY syndrome diagnosed prenatally are mostly found by chance, whereas those who are diagnosed in later childhood come to attention because of cognitive and behavioral problems (Tokita and Sybert, ).…”