婴儿失盐综合征4例病因分析及基因诊断应用价值探讨

Cause analysis and gene diagnosis of infant salt losing syndrome in 4 cases and study of the application value

目的探讨婴儿失盐综合征的病因及基因检测在病因诊断中的应用价值。方法收集2010—2014年上海交通大学附属上海儿童医学中心收治的4例表现为低钠高钾血症的失盐综合征患儿的临床资料、治疗随访情况,并采集该4例患儿及其父母的DNA进行基因检测。结果 4例患儿存在不同程度的失盐。通过基因检测,明确了其存在不同的致病基因突变:分别为CYP21A2基因存在剪接位点变异c.293-13A>G(杂合),小的重复c.923dup T,p.Leu308Phefs*6(杂合);DAX1基因存在小的缺失c.1334del C,p.Ala445Valfs*17(半合子);SCNN1A基因存在小的缺失c.del1311G,p.Arg438Glyfs*43(杂合),剪接位点变异c.1439+1G>C(杂合);CYP11B2基因存在剪接位点变异c.240-1G>A(杂合),无义变异c.1009C>T,p.Gln337*(杂合)。结合临床表现,分别诊断为:先天性肾上腺皮质增生症(21-羟化酶缺乏症);先天性肾上腺发育不良;假性醛固酮减少症I型;醛固酮减少症。结论婴儿失盐综合征病因复杂,容易误诊,基因检测有助于早期明确诊断,进行针对性治疗。

Objective To analyze the causes of infant salt losing syndrome and the application value of gene detection in the diagnosis of the cause. Methods Four cases of salt losing syndrome with low sodium and high potassium admitted from 2010 to 2014 in Shanghai Children＇s Medical Center, Affiliated to Shanghai Jiaotong University School of Medicine were included and clinical data, therapy and follow-up were collected. DNA of children and their parents in the four cases were detected. Results There were different degrees of salt losing situation in the four cases. It found that the patients had different gene mutations through genetic testing： mutations of splicing site [ e.293-13A 〉 G （heterozygous） ] and small duplication [ e .923dupT, p.Leu308Phefs＊6 （heterozygous） ] were detected in CYP21A2, mutation of small deletion [ c. 1334de1C, p.Ala445Valfs＊ 17 （hemizygous） 1 was detected in DAX 1, mutation of splicing site [ c.del 1311G, p.Arg438Glyfs＊43 （heterozygous） ] and point mutation [c.1439＋ 1G 〉 C （heterozygous） ] were detected in SCNN1A and mutation of splicing site [c.240-1G 〉 A （het- erozygous ） ] and nonsense mutation [ c. 1009C 〉 T, p.Gln337＊ （heterozygous） ] were detected in CYP 11B2, respectively. The four cases we,＇ediagnosed as four different diseases： congenital adrenal hyperplasia （21-hydroxylase deficien- cy）, congenital adrenal hypoplasia, pseudohypoaldosteronism type I and hypoaldosteronism. Conclusion The cause of infant salt losing syndrome is complex and is misdiagnosed easily. Gene analysis may be helpful for early diagnosis and treatment.