Carrier screening and prenatal diagnosis for thalassemia-associated mutations in Jiaxing area of Zhejiang / 中华医学遗传学杂志

OBJECTIVE@#To study the molecular epidemiology of thalassemia in Jiaxing area of Zhejiang province and provide a basis for prenatal diagnosis, genetic counseling and prevention and control of birth defects.@*METHODS@#A total of 24 003 pregnant women who presented at the Jiaxing Maternal and Child Health Care Hospital from April 2017 to September 2021 were enrolled. Capillary hemoglobin electrophoresis in combination with routine blood test were used for primary screening for carriers of thalassemia-associated mutations, and those with positive results were subjected to fluorescence quantitative PCR assay. Prenatal diagnosis was provided for couples with a risk of giving birth to children with intermediate or severe thalassemia.@*RESULTS@#Among the 24 003 pregnant women, 1 211 cases were suspected as carriers of thalassemia-associated mutations, among whom 443 (36.58%) were confirmed by genetic testing. Among these, carriers of α-, β- and α-complex β-globin gene mutations have accounted for 27.31% (121/443), 70.65% (313/443) and 2.04% (9/443), respectively. The result of prenatal diagnosis for an at-risk couple was --SEA/αCSα, and the fetus was predicted to have intermediate or severe thalassemia. Termination of the pregnancy was recommended.@*CONCLUSION@#Hemoglobin electrophoresis combined with routine blood test during pregnancy may be used as a preliminary screening measure for carriers of thalassemia-associated variants. Combined with genetic testing, this will be of great significance for the control of thalassemia in this region.

Prenatal diagnosis of a tetrasomy 18p case using BACs-on-Beads technology and single nucleotide polymorphism array / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To determine the origin of a supernumerary small marker chromosome found in a fetus using prenatal BACs-on-Beads (BoBs) and single nucleotide polymorphism array (SNP-array) assays.</p><p><b>METHODS</b>The fetal sample was subjected to chromosomal karyotyping and BoBs analysis, and the results were validated with genome-wide scanning using a SNP microarray.</p><p><b>RESULTS</b>The fetus was found to have a 47,XX,+mar karyotype. BoBs analysis indicated that there was an amplification between 18p11.32 and 18p11.21, which was verified by the SNP-array assay as a 18.3 Mb duplication occurring at 18p11.32q11.1.</p><p><b>CONCLUSION</b>The karyotype of the fetus was determined as 47,XX,+der18(18p11.32?18q11.1::18q11.1?18p11.32). The duplication has involved important genes including SMCHD1, LPIN2 and TGIF1, which may result in severe malformations in the fetus.</p>