Characterization of a novel α-mannosidosis-causing mutation and its use in leukocyte genotyping after bone marrow transplantation

Abstract

α-Mannosidosis is a lysosomal storage disorder caused by deficiency of lysosomal α-mannosidase (LAMAN). Major symptoms include mental retardation, skeletal changes and recurrent infections. Recently, a successful bone marrow transplantation (BMT) in an α-mannosidosis patient was reported. Here we show that this patient was homozygous for a novel mutation, a 1-bp insertion (1197–1198insA) in exon 9 of the LAMAN gene. By using this mutation as a marker, we demonstrate that 1 year post-BMT, the LAMAN genotype of the patient’s leukocytes was identical to that of the donor. This method of genotyping blood cells is a fast and accurate way to monitor the colonization of donor bone marrow cells.