We report a 9-year-old boy with lysinuric protein intolerance (LPI). He had developmental delay, short stature, failure to thrive, high-protein food aversion, hypothyroidism, growth hormone deficiency, features of hemophagocytic lymphohistiocytosis (HLH), decreased bone mineral density and multiple thoracic spine compression fractures on X-ray. LPI was suspected, but urine amino acid profile and normal orotic acid did not suggest biochemical diagnosis of LPI. Targeted next generation sequencing panel for HLH (including SLC7A7) was organized. Due to elevated glutamine in plasma amino acid analysis, a metabolic consultation was initiated and his asymptomatic post-prandial ammonia was 295 μmol/L. We then suspected n-acetylglutamate synthase or carbamoyl-phosphate synthase I deficiency due to marked hyperammonemia, elevated glutamine level, normal orotic acid, and normalization of ammonia at 2 h of carglumic acid (200 mg/kg/d). His targeted next generation sequencing panel for HLH revealed homozygous pathogenic variant in SLC7A7 ((NM_001126106.2): c.726G>A (p.Trp242*)) and confirmed the diagnosis of LPI. We emphasize the importance of genetic investigations in the diagnosis of LPI.

我们报告一个9岁的男孩与赖氨酸尿酸蛋白不耐症（LPI）。他的发育迟缓，身材矮小，无法ive壮成长，对高蛋白食物有厌恶，甲状腺机能减退，生长激素缺乏症，吞噬性淋巴细胞组织细胞增生症（HLH）的特征，骨矿物质密度降低和X线胸片多发性脊柱压缩性骨折。怀疑有LPI，但尿液氨基酸谱和正常乳清酸未提示LPI的生化诊断。组织了针对HLH（包括SLC7A7）的下一代靶向测序小组。由于血浆氨基酸分析中谷氨酰胺升高，开始进行代谢咨询，其无症状的餐后氨水为295μmol/ L。然后，我们怀疑ñ由于明显的高氨血症，谷氨酰胺水平升高，正常的乳清酸以及在2小时的焦磷酸（200 mg / kg / d）氨正常化导致的-乙酰基谷氨酸合酶或氨基甲酰基磷酸合酶I缺乏。他针对HLH的靶向下一代测序小组揭示了SLC7A7中的纯合致病变异（（NM_001126106.2）：c.726G> A（p.Trp242 *））并证实了LPI的诊断。我们强调遗传调查在LPI诊断中的重要性。