Medical Genetics Unit, Santa Maria della Misericordia Hospital, University of Perugia, Perugia, Italy.
Medical Genetics Unit, Department of Medical Sciences, Ferrara University Hospital, Italy.
Am J Med Genet A. 2020 Oct;182(10):2377-2383. doi: 10.1002/ajmg.a.61773. Epub 2020 Aug 3.
Mutations in the MBOAT7 gene have been described in 43 patients, belonging to 18 families, showing nonspecific clinical features (intellectual disability [ID], seizures, microcephaly or macrocephaly, and mild to moderate cerebellar atrophy) that make the clinical diagnosis difficult. Here we report the first Italian patient, a 22.5-year-old female, one of the oldest reported, born to apparently consanguineous parents. She shows severe ID, macrocephaly, seizures, aggressive outbursts, hyperphagia. We also documented progressive atrophy of the cerebellar vermis, that appeared not before the age of 7. The whole-exome sequencing of the trio identified a novel homozygous variant c.1057_1058delGCinsCA (p.Ala353His) in the MBOAT7 gene. The variant is considered to be likely pathogenic, since it is absent from population database and it lies in a highly conserved amino acid residue. This disorder has a neurometabolic pathogenesis, implicating a phospholipid remodeling abnormalities. A brain hydrogen-magnetic resonance spectroscopy (H-MRS) examination in our patient disclosed a peculiar neurometabolic profile in the cerebellar hemispheric region. This new finding could address the clinical suspicion of MBOAT7-related disorder, among the wide range of genetic conditions associated with ID and cerebellar atrophy. Moreover, the documented progression of cerebellar atrophy and the worsening of the disease only after some years open to the possibility of a therapeutic window after birth.
MBOAT7 基因突变已在 43 名患者中被描述,这些患者属于 18 个家族,表现出非特异性的临床特征(智力障碍[ID]、癫痫发作、小头畸形或大头畸形,以及轻度至中度小脑萎缩),这使得临床诊断变得困难。在这里,我们报告了首例意大利患者,一名 22.5 岁的女性,是报道中年龄最大的患者之一,出生于明显近亲结婚的父母。她表现出严重的 ID、大头畸形、癫痫发作、攻击性行为、食欲过盛。我们还记录了小脑蚓部的进行性萎缩,直到 7 岁以后才出现。对三人的全外显子组测序发现了 MBOAT7 基因中的一个新的纯合变异 c.1057_1058delGCinsCA(p.Ala353His)。该变体被认为很可能是致病性的,因为它不存在于人群数据库中,并且位于高度保守的氨基酸残基中。这种疾病具有神经代谢发病机制,涉及磷脂重塑异常。对我们患者的大脑氢磁共振波谱(H-MRS)检查显示小脑半球区域存在特殊的神经代谢特征。这一新发现可以在与 ID 和小脑萎缩相关的广泛遗传条件中,增加对 MBOAT7 相关疾病的临床怀疑。此外,小脑萎缩的进行性进展和疾病的恶化仅在几年后才出现,这为出生后的治疗窗口提供了可能性。