PIK3CA基因变异致巨脑毛细血管畸形多小脑回综合征1例报告并文献复习

Megalencephaly-capillary malformation-polymicrogyria syndrome caused by PIK3CA gene mutation: a case report and literature review

目的 总结PIK3CA基因突变致巨脑毛细血管畸形多小脑回综合征(MCAP)的临床特征。方法 回顾分析1例PIK3CA基因错义突变致MCAP患儿的临床表型、影像学检查结果和随访情况,并复习相关文献。结果 患儿,女,4岁2个月,只会叫爸妈,能理解简单指令,行走步态欠稳,易摔跤。头围56.9cm,腭弓高,左耳廓有一窦道,左侧肢体较右侧肥大,下肢关节过度伸展,肌张力低,肌力Ⅳ级。Gessell评估发育商32。头颅磁共振成像示Chiari畸形Ⅰ型,伴梗阻性脑积水。外显子高通量测序结果显示,PIK3CA基因存在错义变异c.1133G>A,p.Cys378Tyr(杂合),为新生突变,患儿父母此位点均为正常基因型。随访患儿至5岁1个月,能说3~4个字短句,能进行简单语言交流,仍行走不稳,易摔跤,头围57.7cm。结论 发现1例PIK3CA基因新发突变所致MCAP,丰富了PIK3CA基因突变谱。

Objective To explore the clinical features of Megalencephaly-capillary malformation-polymicrogyria syndrome (MCAP) caused by PIK3CA gene mutation. Method The clinical phenotype, imaging findings and follow-up of MCAP caused by missense mutation of PIK3CA gene in a child were retrospectively analyzed, and the related literature was reviewed. Results A girl aged 4 years and 2 months can only say ma, pa and understand simple instructions. She had unsteady walking gait and was easy to fall. The child had a head circumference of 56.9 cm, a high palatal arch, and a sinus tract in the left auricle. The left limb was more hypertrophic than the right side and the lower limb joints were over-extended. She had low muscle tension and the muscle strength was grade IV. Gessell development scales showed the development quotient was 32. Cranial magnetic resonance imaging showed type I chiari malformation with obstructive hydrocephalus. High-throughput exon sequencing results showed that PIK3CA gene had a "missense mutation of c.1133G>A, p.Cys378Tyr (heterozygous)", which was a new mutation. The parents of the children had normal genotypes. The child was followed up to the age of 5 years and 1 month. She could speak short sentences of 3-4 words and communicate in simple language. She was still unsteady in walking and easy to fall, with a head circumference of 57.7 cm. Conclusion A case of MCAP caused by a new mutation of PIK3CA gene was found, which enriched the mutation spectrum of PIK3CA gene.