羧化全酶合成酶缺陷病的临床诊治及基因突变分析

目的：报道羧化全酶合成酶(holocarboxylase synthetas, HCS)缺陷病的诊治及随访情况，了解该疾病的基因突变谱。方法：①采用质谱分析及生物素酶活性测定进行HCS缺陷病的诊断。②采用聚合酶链反应-直接测序法进行HCS基因突变分析。③11例HCS缺陷病患儿中10例接受了生物素的治疗（10~40 mg/d），对其疗效进行随访观察。结果：①11例患儿均有不同程度精神萎靡、嗜睡及代谢性酸中毒，10例患儿有皮肤损害。质谱分析血3-羟基异戊酰肉碱，尿3-甲基巴豆酰甘氨酸、甲基枸橼酸等增高。生物素酶活性与正常对照者生物素酶活性的比值＞30%。②发现4种突变：c.1522C>T（R508W），c.1088T>A（V363D），c.126G>T（E42D），c.1994G>C（R665P）(新变异)。实变频率分别为50%，29%，7%，14%。③10例接受生物素治疗的患儿，1～2周后临床症状消失，2～6月后异常代谢产物多下降至正常。结论：HCS缺陷病以神经系统及皮肤损害、代谢性酸中毒为特征。质谱分析、生物素酶活性测定、基因突变分析有助于明确诊断，口服生物素疗效显著。突变R508W和V363D可能是中国患儿的常见突变。［中国当代儿科杂志，2009，11（8）：609-612］

Diagnosis, treatment and gene mutation analysis in children with holocarboxylase synthetas deficiency

Objective To report the clinical diagnosis,treatment and follow-up of children with holocarboxylase synthetas(HCS)deficiency and explore the gene mutation spectrum of the disease.Methods Eleven children with HCS deficiency were enrolled.Mass spectrometry analysis and biotinidase activity determination were used for diagnosis of HCS deficiency.HCS gene mutations were analyzed by PCR directed sequencing methods.Ten patients received oral biotin treatment(10-40 mg/d).Clinical effects of biotin treatment were observed.Results All 11 cases developed apathetic,lethargy and metabolic acidosis at different degrees,and 10 cases presented with skin lesions.The average blood 3-hydroxyisovaleryl-carnitine concentrations and urinary 3-methylcrontonylglycine and methylcitrate concentrations increased significantly.The biotinidase activity increased,being higher over 30% of the normal reference value.Four mutations in HCS gene were identified,and they were c.1522C>T(R508W),c.1088T>A(V363D),c.126G>T(E42D)and c.1994G>C(R665P)(a new variant)and the frequency was 50%,29%,7% and 14% respectively.The symptoms disappeared in 10 cases 1-2 weeks after biotin treatment,and blood and urinary abnormal metabolites were gradually reduced to normal 2-6 months after treatment.Conclusions HCS deficiency is characterized by nervous system damage,skin lesions and metabolic acidosis.Mass spectrometry analysis,biotinidase activity determination and gene mutation analysis may be helpful in the definite diagnosis of this disorder.The effect of early biotin treatment is satisfactory.The mutations R508W and V363D might be hot-spots in Chinese children with HCS deficiency.