Abstract：
Abetalipoproteinemia (ABL) is a rare recessive genetic disease caused by bi-allelic pathogenic variants in the microsomal triglyceride transfer protein (MTTP) gene. This disease is characterized by a deficiency in the secretion of apolipoprotein B-containing lipoproteins. Patients with ABL present with neurological, hematological, and gastrointestinal symptoms due to fat malabsorption and a deficiency in liposoluble vitamins. In this report, we present a total of four ABL cases, including three new cases, all originating from the same French-Canadian founder population in Saguenay-Lac-Saint-Jean, Québec, Canada. These individuals are homozygous for the same pathogenic variant in the MTTP gene (c.419dup, p.Asn140Lysfs*2). We found that this variant is more common than anticipated in this population, with an estimated carrier frequency of 1:203. Early diagnosis is essential to initiate treatment known to prevent complications associated with ABL. Population carrier screening or newborn screening for ABL should be considered in this French-Canadian founder population.
摘要：
ABL是一种罕见的隐性遗传疾病，由微粒体甘油三酯转移蛋白（MTTP）基因的双等位基因致病变异引起。这种疾病的特征是含有载脂蛋白B的脂蛋白的分泌缺乏。ABL患者存在神经系统，血液学,以及由于脂肪吸收不良和脂溶性维生素缺乏引起的胃肠道症状。在这份报告中,我们总共提供了4例ABL病例，包括三个新病例,所有这些都来自萨格奈-拉克-圣让的法裔加拿大创始人，魁北克,加拿大。这些个体是MTTP基因中相同致病变异的纯合子(c.419dup,P.Asn140Lysfs*2)。我们发现这种变异在这个人群中比预期的更常见，估计载波频率为1:203。早期诊断对于启动已知的预防与ABL相关的并发症的治疗至关重要。在这个法裔加拿大创始人人群中，应考虑进行ABL的人口携带者筛查或新生儿筛查。
