ACAN基因变异致家族性身材矮小一家系报告

摘要

目的 分析家族性矮小家系的临床表型及基因变异特征.方法 回顾1个采用靶向基因高通量测序结合Sanger测序技术确定致病基因的广西壮族地区家族遗传性矮小家系的临床资料.检索相关文献,总结ACAN基因变异患儿的临床表型与基因型的关系.结果 患儿分别为9岁10个月和7岁的两兄弟,身材均矮小;其父母亲身高均为150 cm,非近亲婚配;叔叔和爷爷亦为矮小身材.基因测序证实两兄弟的ACAN基因12号外显子处均存在杂合变异c.6193 delC(p.Gln2065Serfs*27),均遗传自父亲.检索到英文文献11篇,包括本研究在内,在41个家系中发现33个存在ACAN基因致病性变异,包含4个来自中国患儿的变异,但未见中文文献报道.临床表现以特发性矮小最为多见,多为家族性遗传,也可散发.部分患儿还合并有骨关节炎、椎间盘突出或退化等症状.大部分患儿骨龄提前,但亦有部分正常甚至落后.予生长激素联合促性腺激素释放激素类似物推迟青春期治疗可有效改善身高.结论 ACAN基因杂合变异可导致儿童身材矮小,具显著的家系遗传特征,其临床特征与基因型不具备特征性联系.%Objective To explore the clinical phenotype and genetic variation of familial short stature. Method The clinical data of a familial short stature pedigree in Guangxi Zhuang autonomous region were retrospectively analyzed. The disease-causing gene was identified using targeted high-throughput sequencing combined with Sanger sequencing in May 2017. The related literature were searched and the relationship between the clinical phenotype and genotype of the ACAN gene mutation were summarized. Results The two patients were brothers, one was 9-year and 10-month old boy and the other was 7-year-old boy. Both of them had short stature. Their parents were non-consanguineous marriage and both were 150 cm in height, with. Their uncle and grandpa are also short stature. Gene sequencing revealed a novel heterozygous variation c.6193delC (p.Gln2065Serfs*27) in exon 12 of ACAN gene in both brothers, which were inherited from their father. No report of this mutation was found by searching literature and databases. A total of 11 related articles in English were retrieved. Totally (including our study) 32 patients in 41 families were reported to have the pathogenic variants of ACAN gene, including 4 variants from Chinese children, but no such reports were found in Chinese literatures. The most common clinical manifestation is idiopathic short stature, which is mostly familial but could also be sporadic. Some children also suffered from osteoarthritis, disc herniation or degeneration. Most of the children had advanced bone age, but some of them were normal or even lagged. Treatment of postponing puberty by growth hormone combined with gonadotropin-releasing hormone analogues can effectively improve final height. Conclusion Heterozygous mutation of ACAN gene can cause short stature in children and has significant familial genetic characteristics, and the clinical characteristics have no relationship with genotypes.