Yang Y, Ding B, Wang K, Bu D, Tu P, Zhu X
Department of Dermatology, Peking University First Hospital, Beijing, China.
Br J Dermatol. 2004 Jun;150(6):1190-3. doi: 10.1111/j.1365-2133.2004.05938.x.
Xeroderma pigmentosum (XP) is a group of autosomal recessive diseases characterized by hypersensitivity to ultraviolet rays. Among its eight complementation groups, XP group A (XPA) is the most severe type. The XPAC gene has been identified as the defective gene in XPA patients.
To examine genomic DNA from a Chinese family with XPA, to determine the XPAC mutation and, after genetic counselling, to undertake DNA-based prenatal diagnosis in a subsequent pregnancy.
Fetal DNA was extracted from amniotic fluid and used to amplify exon 5 of XPAC containing the potential mutation. Direct sequencing and restriction endonuclease digestion were used for prenatal diagnosis.
We identified a homozygous nonsense XPAC mutation of 631C-->T, which results in an R211X mutation in XPA protein, in the proband. Both her parents are heterozygous. Prenatal diagnosis demonstrated a heterozygous sequence predicting an unaffected child, and a healthy girl was born.
These data provide the first example of a DNA-based prenatal test for genodermatosis in China.
着色性干皮病（XP）是一组常染色体隐性疾病，其特征为对紫外线过敏。在其八个互补组中，XP A组（XPA）是最严重的类型。XPAC基因已被确定为XPA患者中的缺陷基因。
检测一个患有XPA的中国家系的基因组DNA，确定XPAC突变，并在遗传咨询后，对后续妊娠进行基于DNA的产前诊断。
从羊水提取胎儿DNA，用于扩增含有潜在突变的XPAC第5外显子。直接测序和限制性内切酶消化用于产前诊断。
我们在先证者中鉴定出一个纯合的XPAC无义突变631C→T，该突变导致XPA蛋白中的R211X突变。她的父母均为杂合子。产前诊断显示一个杂合序列，预测胎儿未受影响，随后一名健康女婴出生。
这些数据提供了中国首例基于DNA的遗传性皮肤病产前检测实例。
