Department of Pediatrics, Shiga Medical Center for Children, Shiga, Japan.
Department of Pediatrics, Shiga University of Medical Science, Shiga, Japan.
Brain Dev. 2021 Jun;43(6):724-728. doi: 10.1016/j.braindev.2021.02.002. Epub 2021 Mar 11.
The MEHMO (mental retardation, epileptic seizures, hypogonadism and hypogenitalism, microcephaly, and obesity) syndrome, which is caused by a hemizygous variant in the EIF2S3 gene on chromosome Xp22, is associated with significant morbidity and mortality. Refractory epileptic seizures and glucose dysregulation are characteristic manifestations of the MEHMO syndrome, which can often diminish patients' quality of life.
A 5-year-old boy was referred to our hospital because of profound intellectual disability, micropenis, cryptorchidism, central hypothyroidism, and microcephaly. He had neonatal hypoglycemia at birth and later experienced refractory epileptic seizures and developed obesity and insulin-dependent diabetes. A diagnosis of MEHMO syndrome was established on the basis of the patient's clinical manifestations and de novo novel missense variant in the EIF2S3 gene (NM_001415.3:c.805 T > G) that was detected through whole-exome analysis. Although the patient's refractory seizures and diabetes had been well controlled with a combination of ketogenic diet (KD) therapy and insulin therapy, acute fatal necrotizing pancreatitis occurred at the age of 68 months. Moreover, despite intensive care, his condition rapidly deteriorated to multiple organ failure and acute respiratory distress syndrome, resulting in death.
The pathophysiology of glucose intolerance in MEHMO syndrome remains to be elucidated; however, recent studies have suggested that EIF2S3 gene variants could lead to glucose dysregulation and β-cell damage in the pancreas. We suspect that in the present case, KD therapy led to an abnormal load on the beta cells that were damaged owing to eIF2γ dysfunction. Therefore, the adverse effects of KD in patients with MEHMO syndrome should be considered.
MEHMO 综合征(智力障碍、癫痫发作、性腺功能减退和性腺发育不全、小头畸形和肥胖)是由 Xp22 染色体 EIF2S3 基因的半合子变异引起的,与较高的发病率和死亡率相关。难治性癫痫发作和葡萄糖调节异常是 MEHMO 综合征的特征性表现,常导致患者生活质量下降。
一名 5 岁男孩因严重智力障碍、小阴茎、隐睾、中枢性甲状腺功能减退和小头畸形就诊于我院。患儿出生时即有新生儿低血糖,随后出现难治性癫痫发作,并发肥胖和胰岛素依赖型糖尿病。根据患儿的临床表现和通过全外显子组分析发现的 EIF2S3 基因(NM_001415.3:c.805T>G)的新生错义变异,诊断为 MEHMO 综合征。尽管患者的难治性癫痫发作和糖尿病通过酮饮食(KD)疗法联合胰岛素治疗得到了很好的控制,但在 68 月龄时仍发生了急性致命性坏死性胰腺炎。此外,尽管进行了强化治疗,但其病情迅速恶化,导致多器官衰竭和急性呼吸窘迫综合征,最终死亡。
MEHMO 综合征葡萄糖不耐受的病理生理学仍有待阐明;然而,最近的研究表明,EIF2S3 基因突变可能导致胰腺葡萄糖调节异常和β细胞损伤。我们怀疑在本病例中,KD 疗法导致了因 eIF2γ 功能障碍而受损的β细胞异常负荷。因此,应考虑 MEHMO 综合征患者 KD 的不良影响。