As with familial hypertriglyceridemia, genetic determinants of hypotriglyceridemia include ultra-rare monogenic syndromic disorders that are associated with a range of other lipoprotein, biochemical and clinical abnormalities, such as abetalipoproteinemia and homozygous hypobetalipoproteinemia, which result, respectively, from bi-allelic mutations in MTTP and APOB genes encoding, respectively, microsomal TG transfer protein, and apo B [36]. Here, APOB is linked to abetalipoproteinemia.