[Role of the electrophysiologic examination in the diagnosis of Bassen-Kornzweig syndrome]

Clinical features and molecular genetics of two Tunisian families with abetalipoproteinemia

Abetalipoproteinemia (ABL) is a rare monogenic disease characterized by very low plasma levels of cholesterol and triglyceride and almost complete absence of apolipoprotein B (apoB)-containing lipoproteins. Typically, patients present with failure to thrive, acanthocytosis, pigmented retinopathy and neurological features. It has been shown that ABL results from mutations in the gene encoding the microsomal triglyceride transfer protein (MTTP). Sanger sequencing of MTTP was performed for two unrelated consanguineous Tunisian families with two affected individuals each, presenting a more severe ABL phenotype than previously reported in the literature. The patients were found to be homozygous for two novel mutations. In the first family, a nonsense mutation, c.2313T>A, leading to a truncated protein (p.Y771X) was identified. In the second family, a splice mutation, IVS 9+2T>G, was found. These mutations are believed to abolish the assembly and secretion of apoB-containing lipoproteins.

Importance of screening the peripheral smear

A 5-year-old boy presented with history of failure to thrive from infancy. There was a history of one sibling death due to similar problems and history of severe abortions in the mother. Routine examination of peripheral smear revealed more than 50% acanthocytes. Based on this tests were streamlined to doing lipid profile and Lipo protein electrophoresis which revealed hypolipidemia and absent beta hypo protein band. Jejunal mucosal biopsy confirmed the diagnosis of A Beta Lipo proteinemia which revealed lipid laden enterocytes. This case illustrates the importance of simple tests like peripheral smear examination in streamlining further tests in the diagnosis of major diseases.