Ciki Kismet, Alavanda Ceren
Department of Pediatric Metabolism, University of Health Sciences, Van Training and Research Hospital, Van, Turkey.
Department of Medical Genetics, University of Health Sciences, Van Training and Research Hospital, Van, Turkey.
Mol Syndromol. 2024 Dec;15(6):531-536. doi: 10.1159/000539280. Epub 2024 Jun 11.
S-adenosylhomocysteine hydrolase (SAHH) is one of the enzymes involved in converting methionine to homocysteine with transmethylation processes. Methyltransfer reactions are impaired in SAHH deficiency. SAHH deficiency is multisystemic and antenatal onset disorder. It is also ultra rare disease. Only 19 cases have been reported so far.
We report an eighteen-month-old female patient who was investigated due to elevated transaminase levels, coagulopathy, cataract, hypotonia, and global developmental delay. She also had dysmorphic findings. Significant methionine elevation and mild homocysteine elevation were detected. Other metabolic investigations and laboratory findings were unremarkable. Homozygous novel variant in the gene and heterozygous novel variant in the gene were found by whole-exome sequencing (WES) analysis. Methionine restricted diet, phosphatidylcholine, and creatine supplements were advised.
In this report, a case with a novel variant in the gene and prominent dysmorphic findings was reported. More SAHH deficiency cases with different findings and phenotypes will be revealed through the use of WES and genetic panels.
S-腺苷同型半胱氨酸水解酶（SAHH）是参与通过转甲基化过程将蛋氨酸转化为同型半胱氨酸的酶之一。SAHH缺乏时甲基转移反应受损。SAHH缺乏是一种多系统且产前发病的疾病。它也是一种极为罕见的疾病。迄今为止仅报道了19例。
我们报告一名18个月大的女性患者，因转氨酶水平升高、凝血病、白内障、肌张力低下和全面发育迟缓而接受检查。她也有畸形表现。检测到显著的蛋氨酸升高和轻度的同型半胱氨酸升高。其他代谢检查和实验室检查结果无异常。通过全外显子测序（WES）分析在该基因中发现纯合新变异，在另一基因中发现杂合新变异。建议采用限制蛋氨酸饮食、补充磷脂酰胆碱和肌酸。
在本报告中，报道了一例该基因存在新变异且有明显畸形表现的病例。通过使用WES和基因检测板将发现更多具有不同表现和表型的SAHH缺乏病例。
