Cystinosis induced by CTNS gene mutation: a rare disease study.

A boy, aged 1 year and 6 months, was found to have persistent positive urine glucose at the age of 4 months, with polydipsia, polyuria, and growth retardation. Laboratory examinations suggested that the boy had low specific weight urine, anemia, hypokalemia, hyponatremia, hypomagnesemia, metabolic acidosis, glycosuria, acidaminuria, increased fractional excretion of potassium, and decreased tubular reabsorption of phosphate. X-ray examinations of the head, thorax, and right hand showed changes of renal rickets. The slit-lamp examination showed a large number of cystine crystals in the cornea. The genetic testing showed a suspected pathogenic homozygous mutation of the CTNS gene, C.922g>A(p.Gly308Arg). The boy was finally diagnosed with cystinosis. At the beginning of treatment, symptomatic supportive treatment was given to maintain the stability of the internal environment, and cysteamine tartaric acid capsules were used after diagnosis to remove cysteine. This article reported a case of cystinosis caused by CTNS gene mutation and summarized the etiology, clinical features, diagnosis, and treatment of this disease, which can provide a reference for the early diagnosis, treatment, and subsequent study of the disease.1岁6月龄男性患儿，4月龄时发现持续尿糖阳性，伴多饮、多尿、生长迟缓，辅助检查提示患儿存在低比重尿、贫血、低钾血症、低钠血症、低镁血症、代谢性酸中毒、糖尿、氨基酸尿、钾排泄分数增高、肾小管磷重吸收率降低，头颅、胸部及右手腕X线提示肾性佝偻病改变，裂隙灯检查观察到角膜出现大量结晶，基因检查示CTNS基因存在可疑致病性纯合突变c.922G>A(p.Gly308Arg)，该患儿最终诊断为胱氨酸贮积症。治疗初期予对症支持治疗，维持内环境稳定，确诊后特异性应用半胱胺酒石酸胶囊行清除胱氨酸治疗。该文报道了1例CTNS基因突变致胱氨酸贮积症患儿，对该病病因、临床特征、诊疗等进行归纳总结，为该病的早期诊断、治疗及后续研究提供参考依据。.