N-Acylsphingosine Amidohydrolase 2B (ASAH2B)

ASAH2L is a partial duplication of the ASAH2 gene inserted downstream from promoter sequences. ASAH2L has several putative start codons, with the most likely ORF encoding a 109-amino acid protein. Northern blot analysis using probes common to both ASAH2 and ASAH2L and specific to ASAH2 suggested that ASAH2L was expressed predominantly as a 3.5-kb transcript in all tissues examined. RT-PCR showed that ASAH2L was ubiquitously expressed. Comparison of primate and other mammalian genomes indicated that ASAH2L is specific to humans.

ASAH2L was lower in females, decreased with age, and appeared to be further reduced in patients with late-onset AD. The reduction in patients with late-onset AD was more pronounced in those with an affected mother.