Identification of a novel MTTP splice variant c.394-2A>C in an infant with abetalipoproteinemia

Abstract

Abetalipoproteinemia (ABL) is a rare autosomal recessive disorder of lipoprotein metabolism caused by mutations in the microsomal triglyceride transfer protein (MTTP) gene. To date, less than 100 cases of ABL have been reported worldwide. It is characterized biochemically by the absence or extremely low levels of low-density lipoproteins in the blood. We report a four-month-old girl, born to consanguineous parents, who presented with steatorrhea, failure to thrive, marked hypolipidemia and acanthocytosis, with a similar history having been noted in her older sibling. DNA sequencing revealed the infant to be homozygous for a novel pathogenic MTTP splice variant c.394-2A˃C. Family screening revealed her sister to be homozygous for the same MTTP variant while her parents were heterozygotes. Early diagnosis and treatment of ABL in the form of a low-fat diet and fat-soluble vitamin supplementation can mitigate neuropathy and retinopathy. We believe that this is the first identification of an infant with a novel mutation for abetalipoproteinemia in Sri Lanka.