[Novel CHST6 compound heterozygous mutations cause macular corneal dystrophy in a Chinese family].
OBJECTIVE
The aim of this study was to identify mutations of CHST6 gene in a Chinese family with macular corneal dystrophy (MCD) and to investigate the histopathological changes of MCD.


METHODS
Corneal button of the proband was obtained from penetrating keratoplasty for the treatment of severe corneal dystrophy. The sections and ultrathin sections of this specimen were examined under light microscope and transmission electron microscope (TEM). Genomic DNA was extracted from leukocytes in peripheral blood from the family members. The coding region of CHST6 was amplified by polymerase chain reaction (PCR). The PCR products were analyzed by direct sequencing and restriction enzyme digestion.


RESULTS
Histochemical study revealed positive results of colloidal iron stain. TEM revealed enlargement of smooth endoplasmic reticulum and the presence of intracytoplasmic vacuoles. Two mutations, Q298X Y358H, were identified in exon 3 of CHST6. Three patients were compound heterozygotes of these two mutations. The C892T transversion occurred at codon 298 turned the codon of glutamine to a stop codon; the T1072C transversion occurred at codon 358 caused a missense mutation, tyrosine to histidine. All six unaffected family members were heterozygotes. These two mutations were not detected in any of the 100 control subjects.


CONCLUSIONS
The novel compound heterozygous mutation results in loss of CHST6 function and causes the occurrence of MCD. This is the first report of this gene mutation.
Qi
Yan-hua
YH
Department of Ophthalmology, Second Affiliated Hospital of Harbin Medicine University, Harbin 150086, China. qyh64@hotmail.com
Dang
Xiu-hong
XH
Su
Hong
H
Zhou
Nan
N
Liang
Ting
T
Wang
Zheng
Z
Huang
Shang-zhi
SZ
D044466:Asian People / Q000235:genetics; D003317:Corneal Dystrophies, Hereditary / Q000235:genetics*; D006579:Heterozygote; D006801:Humans; D009154:Mutation; D010375:Pedigree; D015238:Sulfotransferases / Q000235:genetics*; D000097811:Carbohydrate Sulfotransferases
D015238:Sulfotransferases; D000097811:Carbohydrate Sulfotransferases