X连锁遗传性脑积水的L1CAM基因突变检测及产前诊断

目的探讨X连锁遗传性脑积水的L1CAM基因突变检测和产前诊断的可行性。方法应用PCR-直接序列测定法对一个X连锁遗传性脑积水家系进行L1CAM基因突变分析,并对孕妇进行了产前诊断。结果该家系先证者在L1CAM基因外显子28存在c.3581CT(p.S1194L)致病突变,患者的姐姐和母亲均为携带者,姨和表妹均未检测到该致病突变。对携带有该基因突变的姐姐先后进行了3次产前基因诊断(包括1例羊水检测,1例双胎羊水检测,1例绒毛检测),均证实为获得致病突变的男性胎儿。结论对于B超发现的男性脑积水胎儿,可以对其进行L1CAM基因突变筛查,有助于对下次妊娠的复发风险或携带者的妊娠风险进行评估;对携带突变基因的孕妇进行产前诊断,避免患儿的出生。

Detection of L1 CAM mutation and prenatal diagnosis of X-linked hydrocephalus

Objective: To evaluate the feasibility of Chinese X-linked hydrocephalus by detection of L1 CAM mutation.
Methods: PCR-direct sequencing was used to detect L1CAM gene mutation in a congenital hydrocephalus family. Prenatal diagnoses were then performed by chorionic villus or amniotic fluid samples.
Results: L1CAM exon 28 mutation c. 3581C>T ( p. S1194L) was detected in this family. The Patient’ s mother and sister were c. 3581C>T mutation carrier,and her aunt and cousin were the normal genotypes. Prenatal diagnosis was conducted in the carrier sister successively for three times. The samples of amniotic fluid or chorionic villi of four male fetuses including one twins fetuses with gene mutation were detected successfully.
Conclusions: Detection of L1 CAM genetic mutation should be conducted if a male fetus is found to have congenital hydrocephalus by type-B ultrasound. It is useful to evaluate the recurrence risk of congenital hydrocephalus. It is necessary to do prenatal examination for the pregnancy women who is L1 CAM gene mutation carrier to avoid the children suffered congenital hydrocephalus to born.