目的 探讨河南地区失盐型21⁃羟化酶缺乏症（21⁃hydroxylase deficiency, 21⁃OHD）患儿临床及遗传学特点。 方法 回顾性分析2007年8月—2023年11月在河南省儿童医院内分泌遗传代谢科就诊的165例失盐型21⁃OHD患儿的临床特点、实验室检查、遗传学检测结果，分析临床特点与遗传学之间的关系。 结果 生物学男性100例，女性65例；男性中位诊断年龄40 d，女性中位诊断年龄28 d。皮肤黏膜色素沉着155例（93.9%），呕吐151例（91.5%），体重不增153例（92.7%），161例（97.6%）就诊时出现肾上腺危象，所有女性均有阴蒂肥大；83.0%（137/165）血钾>5.5 mmol/L，93.9%（155/165）血钠<135 mmol/L，96.4%（159/165）血促肾上腺皮质激素（adrenocorticotropic hormone, ACTH）升高，90.3%（149/165）患儿血皮质醇降低，100%（165/165）患儿血睾酮（testosterone, T）、17⁃羟孕酮（17⁃hydroxyprogesterone, 17⁃OHP）升高，6例社会性别为男性的患儿染色体核型为46,XX；所有患儿均携带CYP21A2纯合或复合杂合致病性变异，检出29种类型的变异共330个，最常见的为c.293⁃13A/C>G（37.3%）和大片段缺失（22.4%），20例携带CYP21A2与CYP21A1P基因重组；各基因型组之间17⁃OHP水平差异有统计学意义（P<0.05），血钾、血钠、ACTH、T、皮质醇差异无统计学意义（P>0.05）。 结论 失盐型21⁃OHD多以肾上腺危象起病，高钾血症、低钠血症以及17⁃OHP、T、ACTH升高和皮质醇降低有助于该疾病的诊断，最终确诊仍需基因检测，基因型并不能完全预测临床表型。

Objective To explore the clinical and genetic characteristics of children with salt-wasting (SW) 21-hydroxylase deficiency (21-OHD) in Henan Province. Methods Clinical characteristics, laboratory results, and genetic findings were retrospectively reviewed for 165 children with SW 21-OHD who presented to the Department of Endocrinology and Genetic Metabolism, Children's Hospital Affiliated to Zhengzhou University, from August 2007 to November 2023. Associations between clinical characteristics and genotypes were analyzed. Results Of the 165 patients, 100 were biologically male and 65 female. The median age at diagnosis was 40 days in males and 28 days in females. Skin and mucosal hyperpigmentation occurred in 155 patients (93.9%), vomiting in 151 patients (91.5%), and failure to gain weight in 153 patients (92.7%). All females had clitoral hypertrophy. At presentation, 161 (97.6%) had adrenal crisis. Hyperkalemia (serum potassium >5.5 mmol/L) was present in 83.0% (137/165), and hyponatremia (serum sodium <135 mmol/L) in 93.9% (155/165). Elevated adrenocorticotropic hormone (ACTH) occurred in 96.4% (159/165), decreased cortisol in 90.3% (149/165), and elevated testosterone and 17-hydroxyprogesterone (17-OHP) in 100% (165/165). Six patients with male social gender had a 46,XX karyotype. All patients carried homozygous or compound heterozygous pathogenic variants in CYP21A2; 330 variants representing 29 types were identified, with c.293-13A/C>G (37.3%) and large deletions (22.4%) being most common. Twenty patients carried recombinant alleles between CYP21A2 and CYP21A1P. Across genotype groups, serum potassium, sodium, ACTH, testosterone, and cortisol showed no statistically significant differences (P>0.05), whereas 17-OHP levels differed significantly (P<0.05). Conclusions SW 21-OHD typically presents with adrenal crisis. Hyperkalemia, hyponatremia, elevated 17-OHP, testosterone, and ACTH, together with decreased cortisol, support the diagnosis; definitive confirmation requires genetic testing. Genotype does not fully predict clinical phenotype.