A recent study in Genetics in Medicine aiming at the identification by whole-exome sequencing of genes involved in infantile nystagmus found heterozygous missense mutations in the MANBA gene, which the encodes lysosomal beta-mannosidase. The mutations resulted in decrease of ?-mannosidase activities in the patients as well as in mutant-transfected HEK293T cells.
MANBA is expressed in the pretectal nucleus of the developing midbrain, known to be involved in oculomotor and optokinetic nystagmus. Further analysis revealed that nystagmus is present in at least 24 different lysosomal storage diseases involving the brain.
This is the first identification of MANBA mutations in patients with autosomal-dominant nystagmus, suggesting a new clinical entity.
Posted by Nicola Brunetti-Pierri