Kumar Arun, Bhattacharjee Soma, Prakash Durgappa Ravi, Sadanand Chethan Sitarampur
Department of Molecular Reproduction, Development and Genetics, Indian Institute of Science, Bangalore, India.
Mol Vis. 2007 Jan 16;13:39-46.
The autosomal recessive form of congenital hereditary endothelial dystrophy (CHED2) is a rare eye disorder caused by mutations in the SLC4A11 gene located at the CHED2 locus on chromosome 20p13-p12. The purpose of this study was to carry out genetic analysis of CHED2 in two Indian families.
Blood samples were collected from individuals for genomic DNA isolation. In order to see if these families had mutations in the SLC4A11 gene, we selected 11 microsatellite markers from the CHED2 candidate region and used them to genotype the families. DNA sequence analysis was used for mutation detection. Allele-specific PCR was used to determine the segregation of mutations in families and also to determine if the mutations were present in 100 ethnically matched normal control chromosomes.
Haplotype analysis suggested linkage of the disorder to the CHED2 locus in both families. DNA sequence analysis showed a novel indel mutation, c.859_862delGAGAinsCCT (E287fsX21) in exon 8 of the SLC4A11 gene in one family. This mutation is predicted to truncate the protein with a lack of all 14 transmembrane domains. DNA sequence analysis of the second family showed a novel in-frame deletion mutation c.2014_2016delTTC or 2017_2019delTTC which will lead to the loss of a phenylalanine residue at position 672 or 673 (F672del or F673del). The mutant protein is expected to lack a conserved phenylalanine residue in transmembrane domain number 8.
This study reports two novel mutations in two CHED2 families and increases the spectrum of mutations in SLC4A11 to a total of 16. PCR-based screening methods were developed for both mutations for rapid screening of individuals.
常染色体隐性先天性遗传性内皮营养不良（CHED2）是一种罕见的眼部疾病，由位于20号染色体p13 - p12区域CHED2位点的SLC4A11基因突变引起。本研究旨在对两个印度家庭的CHED2进行基因分析。
采集个体血液样本用于基因组DNA提取。为检测这些家庭的SLC4A11基因是否存在突变，我们从CHED2候选区域选择了11个微卫星标记，用于对这些家庭进行基因分型。采用DNA序列分析进行突变检测。等位基因特异性PCR用于确定家庭中突变的分离情况，并确定这些突变是否存在于100条种族匹配的正常对照染色体中。
单倍型分析表明两个家庭的该疾病均与CHED2位点连锁。DNA序列分析显示，一个家庭的SLC4A11基因第8外显子存在一个新的插入缺失突变，即c.859_862delGAGAinsCCT（E287fsX21）。预计该突变会使蛋白质截短，缺失所有14个跨膜结构域。对第二个家庭的DNA序列分析显示存在一个新的框内缺失突变，即c.2014_2016delTTC或2017_2019delTTC，这将导致第672位或673位苯丙氨酸残基缺失（F672del或F673del）。预计突变蛋白在第8个跨膜结构域中会缺失一个保守的苯丙氨酸残基。
本研究报告了两个CHED2家庭中的两个新突变，使SLC4A11基因的突变谱增加至16种。针对这两种突变开发了基于PCR的筛查方法，用于个体的快速筛查。
