Detecting the Difficult: An Intronic NPC1 Variant Hiding in Plain Sight.

An illustration of the importance of manual data review for identifying rare intronic variants adjacent to homopolymers is presented here. A 14-year-old male with Niemann-Pick Type C disease confirmed biochemically was only found to have a heterozygous pathogenic variant by molecular analysis. A manual review of the Next Generation Sequencing (NGS) data identified a c.