Impact of Huntington Disease Gene-Positive Status on Pre-Symptomatic Young Adults and Recommendations for Genetic Counselors.

Huntington disease (HD) is an autosomal dominant, progressive neurodegenerative disorder for which there is no cure. Predictive testing for HD is available to asymptomatic at-risk individuals. Approximately half of the population undergoing predictive testing for HD consists of young adults (≤35 years old). Finishing one's education, starting a career, engaging in romantic relationships and becoming a parent are key milestones of young adulthood. We conducted a qualitative study to explore how testing gene-positive for HD influences young adults' attainment of these milestones, and to identify major challenges that pre-symptomatic young adults face to aid the development of targeted genetic counseling. Results of our study demonstrate that 1) knowing one's gene-positive status results in an urgency to reach milestones and positively changes young adults' approach to life; 2) testing positive influences young adults' education and career choices, romantic relationships, and family planning; 3) young adults desire flexible and tailored genetic counseling to address needs and concerns unique to this population. Findings of this study contribute to the understanding of the impact of predictive testing for HD on young adults, and highlight issues unique to this population that call for further research, intervention and advocacy.

Simplifying the ultrasound findings of the major fetal chromosomal aneuploidies.

Sonographic aneuploidy markers and structural anomalies associated with the 5 most common chromosomal aneuploidies are organized and simplified to highlight the many sonographic findings that are commonly seen with each aneuploidy. Identification of these findings allows families to have the option to pursue prenatal genetic testing to confirm or exclude chromosomal abnormalities suggested by such prenatal ultrasound findings and make informed decisions about the subsequent management of their pregnancy. We review the most common major human chromosomal aneuploidies, including trisomies 21, 18, and 13; Turner syndrome; and triploidy. The focus is on the major structural anomalies seen with each of these, as well as ultrasound markers (findings associated with increased risk of chromosomal abnormality but also seen in normal fetuses). The role of clinical information such as maternal serum screening and new cell-free fetal DNA screening is also reviewed. As patients do not usually present for fetal ultrasound with a known diagnosis, a concise knowledge of ultrasound and clinical findings will alert radiologists to concerning cases and prompt a guided search for important associated anomalies. Fetal ultrasound can be challenging owing to the many findings and sometimes technically difficult evaluation. By simplifying the ultrasound findings seen with the major chromosomal abnormalities and highlighting the role of clinical history, we hope that an informed search for specific sonographic findings can be performed; thereby, reducing missed diagnoses.

Impact of Cell-Free Fetal DNA Screening on Patients' Choice of Invasive Procedures after a Positive California Prenatal Screen Result.

Until recently, maternal serum analyte levels paired with sonographic fetal nuchal translucency measurement was the most accurate prenatal screen available for Trisomies 18 and 21, (91% and 94% detection and false positive rates of 0.31% and 4.5% respectively). Women with positive California Prenatal Screening Program (CPSP) results have the option of diagnostic testing to determine definitively if the fetus has a chromosomal abnormality. Cell-free fetal (cff-) DNA screening for Trisomies 13, 18, and 21 was first offered in 2012, allowing women with positive screens to choose additional screening before diagnostic testing. Cff-DNA sensitivity rates are as high as 99.9% and 99.1%, with false positive rates of 0.4% and 0.1%, for Trisomies 18 and 21, respectively. A retrospective chart review was performed in 2012 on 500 CPSP referrals at the University of California, San Diego Thornton Hospital. Data were collected prior to and after the introduction of cff-DNA. There was a significant increase in the number of participants who chose to pursue additional testing and a decrease in the number of invasive procedures performed after cff-DNA screening was available. We conclude that as fetal aneuploidy screening improves, the number of invasive procedures will continue to decrease.