A New Case of Abetalipoproteinemia Caused by Novel Compound Heterozygote Mutations in the MTTP Gene without Fat or Vitamin Malabsorption

Abetalipoproteinemia (ABL) is a rare disease characterized by extremely low apolipoprotein B (apoB) -containing lipoprotein levels, dietary fat, and fat-soluble vitamin malabsorption, leading to gastrointestinal, neuromuscular, and ophthalmological symptoms. We herein report a case of ABL with novel compound heterozygous mutations in the microsomal triglyceride transfer protein gene (c. 1686₁687del p. Ser563TyrfsTer10 and c. 1862T>C p. Ile621Thr), identified via panel sequencing. Although the patient had extremely reduced low-density lipoprotein cholesterol levels and a fatty liver, he did not exhibit other typical complications. Furthermore, unlike typical ABL, this patient had a preserved apoB-48 secretion and increased concentrations of high-density lipoprotein cholesterol, which may account for the normal serum fat-soluble vitamin levels.