Slavotinek A M, Moshrefi A, Lopez Jiminez N, Chao R, Mendell A, Shaw G M, Pennacchio L A, Bates M D
Department of Pediatrics, Division of Genetics, University of California, San Francisco, 533 Parnassus Street, Room U585P, San Francisco, CA 94143-0748, USA.
Clin Genet. 2009 May;75(5):429-39. doi: 10.1111/j.1399-0004.2009.01182.x.
Congenital diaphragmatic hernia (CDH) is a common birth defect for which few causative genes have been identified. Several candidate regions containing genes necessary for normal diaphragm development have been identified, including a 4-5 Mb deleted region at chromosome 1q41-1q42 from which the causative gene(s) has/have not been cloned. We selected the HLX gene from this interval as a candidate gene for CDH, as the Hlx homozygous null mouse has been reported to have diaphragmatic defects and the gene was described as being expressed in the murine diaphragm. We re-sequenced HLX in 119 CDH patients and identified four novel single nucleotide substitutions that predict amino acid changes: p.S12F, p.S18L, p.D173Y and p.A235V. These sequence alterations were all present in patients with isolated CDH, although patients with both isolated CHD and CDH with additional anomalies were studied. The single-nucleotide substitutions were absent in more than 186 control chromosomes. In-situ hybridization studies confirmed expression of Hlx in the developing murine diaphragm at the site of the junction of the diaphragm and the liver. Although functional studies to determine if these novel sequence variants altered the inductive activity of Hlx on the alpha-smooth muscle actin and SM22alpha promoters showed no significant differences between the variants and wild-type Hlx, sequence variants in HLX may still be relevant in the pathogenesis of CDH in combination with additional genetic and environmental factors.
先天性膈疝（CDH）是一种常见的出生缺陷，目前已确定的致病基因很少。已确定了几个包含正常膈肌发育所需基因的候选区域，包括1号染色体1q41 - 1q42处一个4 - 5 Mb的缺失区域，该区域的致病基因尚未被克隆。我们从这个区间选择HLX基因作为CDH的候选基因，因为据报道Hlx纯合缺失小鼠存在膈肌缺陷，且该基因在小鼠膈肌中表达。我们对119例CDH患者的HLX基因进行了重测序，鉴定出四个预测氨基酸变化的新型单核苷酸替换：p.S12F、p.S18L、p.D173Y和p.A235V。这些序列改变均出现在孤立性CDH患者中，尽管我们研究了孤立性先天性心脏病（CHD）合并CDH及其他异常的患者。在超过186条对照染色体中未发现这些单核苷酸替换。原位杂交研究证实Hlx在发育中的小鼠膈肌与肝脏交界处表达。尽管功能研究表明这些新型序列变体并未改变Hlx对α-平滑肌肌动蛋白和SM22α启动子的诱导活性，但HLX中的序列变体可能仍与CDH的发病机制有关，可能与其他遗传和环境因素共同作用。
