Prenatal Diagnosis of Sex Chromosome Abnormalities

Milunsky, Jeff M.

doi:10.1002/9781118981559.ch5

Cited by 4 publications

(6 citation statements)

References 456 publications

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“…Compared with 47,XXX, 47,XYY, and mosaicism, 45,X and 47,XXY have more severe phenotypes, including abnormal sexual development, infertility, and physical problems. Mosaicism has variable phenotypes and generally has a better prognosis . This study showed that pregnant women with history of infertility were more likely to continue their affected pregnancies.…”

Section: Discussionmentioning

confidence: 66%

“…SCA are relatively common genetic conditions, with an overall incidence of 1 in 400, approximately twice as frequent in newborns as trisomy 21 . Some individuals with SCA, in particular those with 47,XXX, 47,XYY, and mosaic SCA, may not have any phenotypic consequences and are not identified throughout their lifetimes . The most common symptoms are not life‐threatening and are associated with highly variable degrees of clinical problems in the physical, reproductive, and behavioral domains (Table ) .…”

Section: Introductionmentioning

confidence: 99%

“…Some individuals with SCA, in particular those with 47,XXX, 47,XYY, and mosaic SCA, may not have any phenotypic consequences and are not identified throughout their lifetimes . The most common symptoms are not life‐threatening and are associated with highly variable degrees of clinical problems in the physical, reproductive, and behavioral domains (Table ) . These individuals can usually adapt to normal adult life .…”

Section: Introductionmentioning

confidence: 99%

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Parental decisions following prenatal diagnosis of sex chromosome aneuploidy in Hong Kong

Cheng

Cheuk

et al. 2017

J of Obstet and Gynaecol

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Section: Discussionmentioning

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Parental decisions following prenatal diagnosis of sex chromosome aneuploidy in Hong Kong

Cheng

Cheuk

et al. 2017

J of Obstet and Gynaecol

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“…The argument can also be made that severity of the condition, per se , should not necessarily be the determining criteria for testing. As with sex‐chromosome abnormalities, prenatal detection can be justifiable because of the opportunities it provides for early therapeutic, educational and psychologic interventions .…”

Section: Discussionmentioning

confidence: 99%

Expanding non‐invasive prenatal testing beyond chromosomes 21, 18, 13, X and Y

Benn

2016

Clinical Genetics

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Non-invasive prenatal testing (NIPT) based on cell-free DNA in maternal plasma is being expanded to include additional chromosome abnormalities beyond those involving chromosomes 21, 18, 13, X and Y. Review of population cytogenetic data provides insight into the likely number of additional abnormalities detectable. Additional clinically significant and cytogenetically recognizable abnormalities are present in less than 0.1% of newborns but clinically significant, or potentially significant, sub-microscopic imbalances are expected to be present in 1.7%. Cytogenetic studies on chorionic villus samples suggests that after excluding abnormalities involving chromosomes 21, 18, 13, X and Y, approximately 0.6% of NIPT results may be positive for an unbalanced abnormality attributable to mosaicism but most of these will not be confirmed at amniocentesis or in newborns. NIPT has also been developed for specific microdeletion syndromes and initial experience is now available. Laboratory procedures such as deeper sequencing and additional data analytics are rapidly evolving but even with existing protocols, it is already clear that NIPT does not necessarily need to be limited to trisomies 21, 18, 13 and the sex-chromosome abnormalities. Patient educational materials and genetic counseling services need to be available for women offered expanded NIPT.

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“…Since 2013, some NIPT platforms have included sex chromosome abnormality (SCA) analysis along with the three common autosomal aneuploidies (Swanson, Sehnert, & Bhatt, ). As a group, SCAs are the most common chromosome abnormalities present at birth, occurring in every 1 in 300–400 live births (Milunsky, ). The most common SCA conditions are 45,X (Turner syndrome) and 47,XXY (Klinefelter syndrome).…”

Section: Introductionmentioning

confidence: 99%

Current genetic counseling practice in the United States following positive non‐invasive prenatal testing for sex chromosome abnormalities

Fleddermann

Hashmi

Stevens

et al. 2019

Journal of Genetic Counseling

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The purpose of this study was to describe current genetic counseling practice in the United States following a non‐invasive prenatal testing (NIPT) result positive for a sex chromosome abnormality (SCA). Screening for SCAs can be confounded by confined placental mosaicism, natural loss of the X chromosome from maternal cells during aging, and undiagnosed maternal SCA or copy number variant (CNV). Furthermore, with the exception of 45,X, individuals with SCAs usually have no ultrasound or postnatal findings. This makes follow‐up for unresolved positive NIPT necessary; however, there are currently no clinical guidelines. This study used a cross‐sectional design with an anonymous questionnaire to survey 176 genetic counselors. The majority of prenatal respondents always offered diagnostic testing (>88%) and anatomy ultrasound (~90%), but the percent consistently offering maternal karyotype (22%–52%) and postnatal evaluation (28%–87%) varied. Maternal karyotype was offered more often when NIPT was positive for 45,X or 47,XXX and patients had normal prenatal diagnostic testing (p < 0.02) or declined testing (p < 0.02). Offer of postnatal evaluation was more likely when diagnostic testing was declined (p < 0.001). The majority of pediatric providers always offered a postnatal karyotype for the newborn (>72%) but the percent offering maternal karyotype (6%–46%) varied widely. With the current inconsistencies, many newborns with undiagnosed SCAs who could benefit from growth hormone therapy, early intervention, and/or targeted surveillance may be missed. Therefore, there is a need for professional guidelines to help improve the consistency of clinical care for patients with NIPT results positive for SCAs.

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Prenatal Diagnosis of Sex Chromosome Abnormalities

Cited by 4 publications

References 456 publications

Parental decisions following prenatal diagnosis of sex chromosome aneuploidy in Hong Kong

Parental decisions following prenatal diagnosis of sex chromosome aneuploidy in Hong Kong

Expanding non‐invasive prenatal testing beyond chromosomes 21, 18, 13, X and Y

Current genetic counseling practice in the United States following positive non‐invasive prenatal testing for sex chromosome abnormalities

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