Dubey Sudhisha, Tardy Veronique, Chowdhury Madhumita Roy, Gupta Neerja, Jain Vandana, Deka Deepika, Sharma Pankaj, Morel Yves, Kabra Madhulika
Department of Pediatrics, Division of Genetics, All India Institute of Medical Sciences, New Delhi, India.
Department of Molecular Endocrinology and Rare Diseases, Center for Biology and Eastern Pathology, Civil Hospitals of Lyon, Bron Cedex, France.
Indian J Med Res. 2017 Feb;145(2):194-202. doi: 10.4103/ijmr.IJMR_329_16.
BACKGROUND & OBJECTIVES: Congenital adrenal hyperplasia (CAH) is an autosomal recessive disorder with a wide range of clinical manifestations. The disease is attributed to mutations in CYP21A2 gene encoding 21-hydroxylase enzyme. In view of severe phenotype in salt-losing cases, issues related to genital ambiguity in girls and precocity in boys, most families opt for prenatal testing and termination of affected foetus. CAH can be diagnosed in utero through direct molecular analysis of CYP21A2 gene, using DNA extracted from foetal tissues or cells obtained from chorionic villus sampling or amniocentesis. The objective of this study was to evaluate the feasibility and accuracy of prenatal diagnosis (PND) using sequencing and multiplex ligation probe amplification (MLPA) methods in families at risk for CAH.
Fifteen pregnant women at risk of having an affected offspring with CAH were included in this study. Ten families had previous affected children with salt-wasting/simple virilising form of CAH and five families did not have live children but had a high index of suspicion for CAH in previous children based on history or records. Mutation analysis was carried out by Sanger sequencing and MLPA method.
Seven different mutations were identified in 15 families. Deletions and I2g mutation were the most common. Of the 15 foetuses analyzed, nine were unaffected while six were affected. Unaffected foetuses were delivered, they were clinically normal and their genotype was found to be concordant to the prenatal report. All except two families reported in the second trimester. None of the couples opted for prenatal treatment.
INTERPRETATION & CONCLUSIONS: Our preliminary findings show that PND by direct mutation analysis along with MLPA is a feasible strategy that can be offered to families at risk.
先天性肾上腺皮质增生症（CAH）是一种常染色体隐性疾病，临床表现多样。该疾病归因于编码21-羟化酶的CYP21A2基因突变。鉴于失盐型病例的严重表型、女孩生殖器模糊及男孩性早熟等问题，大多数家庭选择进行产前检测并终止患病胎儿妊娠。CAH可通过对CYP21A2基因进行直接分子分析在子宫内诊断，使用从胎儿组织或经绒毛取样或羊膜穿刺术获得的细胞中提取的DNA。本研究的目的是评估在有CAH风险的家庭中使用测序和多重连接探针扩增（MLPA）方法进行产前诊断（PND）的可行性和准确性。
本研究纳入了15名有生育CAH患儿风险的孕妇。其中10个家庭曾有患失盐/单纯男性化型CAH的患儿，5个家庭没有存活子女，但根据病史或记录，其之前的孩子高度怀疑患有CAH。通过桑格测序和MLPA方法进行突变分析。
在15个家庭中鉴定出7种不同的突变。缺失和I2g突变最为常见。在分析的15例胎儿中，9例未受影响，6例受影响。未受影响的胎儿出生后临床正常，其基因型与产前报告一致。除2个家庭外，所有家庭均在孕中期报告。没有一对夫妇选择产前治疗。
我们的初步研究结果表明，通过直接突变分析联合MLPA进行PND是一种可行的策略，可为有风险的家庭提供。
