Cheng Ying, Liang Hong, Cai Na-Li, Guo Li, Huang Yu-Ge, Song Yuan-Zong
Department of Pediatrics, First Affiliated Hospital, Jinan University, Guangzhou 510630, China.
Zhongguo Dang Dai Er Ke Za Zhi. 2017 Sep;19(9):968-974. doi: 10.7499/j.issn.1008-8830.2017.09.007.
Microvillus inclusion disease (MVID) is an autosomal recessive disorder caused by biallelic mutations in the MYO5B or STX3 gene. Refractory diarrhea and malabsorption are the main clinical manifestations. The aim of this study was to investigate the clinical features and MYO5B gene mutations of an infant with MVID. A 21-day-old female infant was referred to the hospital with the complaint of diarrhea for 20 days. On physical examination, growth retardation of the body weight and length was found along with moderately jaundiced skin and sclera. Breath sounds were clear in the two lungs and the heart sounds were normal. The abdomen was distended and the veins in the abdominal wall were observed. The liver and spleen were not palpable. Biochemical analysis revealed raised serum total bile acids, bilirubin, transaminases and γ-glutamyl transpeptidase while decreased levels of serum sodium, chloride, phosphate and magnesium. Blood gas analysis indicated metabolic acidosis. The preliminary diagnosis was congenital diarrhea, and thus parenteral nutrition was given along with other symptomatic and supportive measures. However, diarrhea, metabolic acidosis and electrolyte disturbance were intractable, and the cholestatic indices, including transaminases, γ-glutamyl transpeptidase, bilirubin and total bile acids, remained at increased levels. One month later, the patient was discharged and then lost contact. On genetic analysis, the infant was proved to be a compound heterozygote of the c.310+2Tdup and c.1966C>T(p.R656C) variants of the gene MYO5B, with c.310+2Tdup being a novel splice-site mutation. MVID was thus definitely diagnosed.
微绒毛包涵体病（MVID）是一种常染色体隐性疾病，由MYO5B或STX3基因的双等位基因突变引起。难治性腹泻和吸收不良是主要临床表现。本研究旨在调查一名患有MVID的婴儿的临床特征和MYO5B基因突变情况。一名21日龄女婴因腹泻20天被转诊至我院。体格检查发现体重和身长发育迟缓，皮肤和巩膜中度黄疸。双肺呼吸音清晰，心音正常。腹部膨隆，可见腹壁静脉。肝脏和脾脏未触及。生化分析显示血清总胆汁酸、胆红素、转氨酶和γ-谷氨酰转肽酶升高，而血清钠、氯、磷酸盐和镁水平降低。血气分析提示代谢性酸中毒。初步诊断为先天性腹泻，因此给予肠外营养及其他对症支持治疗。然而，腹泻、代谢性酸中毒和电解质紊乱难以控制，包括转氨酶、γ-谷氨酰转肽酶、胆红素和总胆汁酸在内的胆汁淤积指标仍处于升高水平。1个月后，患者出院，随后失去联系。基因分析显示，该婴儿为MYO5B基因c.310+2Tdup和c.1966C>T（p.R656C）变异的复合杂合子，其中c.310+2Tdup为新的剪接位点突变。由此确诊为MVID。
