Absence of heterozygosity detected by single-nucleotide polymorphism array in prenatal diagnosis.

A new interesting article has been published in Ultrasound Obstet Gynecol. 2019 Dec 16. doi: 10.1002/uog.21951. and titled:

Absence of heterozygosity detected by single-nucleotide polymorphism array in prenatal diagnosis.

Authors of this article are:

Liu J, He Z, Lin S, Wang Y, Huang L, Huang X, Luo Y.

A summary of the article is shown below:

OBJECTIVES: We aimed to investigate the general occurrence and clinical significance of absence of heterozygosity (AOH), detected by single-nucleotide polymorphism (SNP) array, in prenatal diagnosis.METHODS: We recruited 10,294 pregnant women undergoing invasive prenatal diagnosis at our fetal medicine center over 6 years. All women underwent SNP array using the Affymetrix CytoScan HD array platform. AOH was defined as a chromosomal homozygosity segment with neutral copy number. AOH cases with size over 10 Mb were further analyzed, and the clinical features were reviewed.RESULTS: In total, 100 patients (0.97%, 100/10294) with AOH were identified; in 81% of these (81/100), AOH occurred in a single chromosome, while 19% of the patients (19/100) had multiple AOHs in different chromosomes. AOH was observed on all chromosomes, and chromosome X, 2, and 16 were the most frequently involved. The length of AOH ranged from partial chromosome (9.002-80.222 Mb) to the entire chromosome. Similar AOH regions displayed varied clinical manifestations. In total, 55 patients presented with concomitant ultrasound abnormalities, and the most common ultrasonographic abnormalities were multiple abnormalities (25.5%, 14/55), genitourinary malformations (14.5%, 8/55), and fetal growth restriction (9.1%, 5/55). Notably, the rate of adverse perinatal outcomes in fetuses with AOH and ultrasound abnormalities (64.6%, 31/48) was higher than the rate in fetuses with AOH but without ultrasound abnormalities (14.3%, 5/35). Further, non-invasive prenatal testing using cell-free fetal DNA from maternal blood indicated chromosomal copy number abnormalities in 11 patients; however, they were confirmed as AOH through SNP array of the amniotic fluid.CONCLUSIONS: Genetic counseling regarding AOH in prenatal diagnosis remains challenging. To comprehensively evaluate its significance, we propose a management strategy involving further serial ultrasound examinations, parental verification, whole-exome sequencing, placental study, and effective follow-up. This article is protected by copyright. All rights reserved.This article is protected by copyright. All rights reserved.

Check out the article’s website on Pubmed for more information:

[link-preview url=https://www.ncbi.nlm.nih.gov/pubmed/31840905 forceshot=true]

This article is a good source of information and a good way to become familiar with topics such as: Absence of heterozygosity; Chromosomal microarray analysis; Genetic counseling; Loss of heterozygosity; Prenatal diagnosis; Single-nucleotide polymorphism array; Uniparental disomy.

NativeFolder: The Only Bacterial Culture Medium for the Expression of Soluble Proteins