Initially identified in an analysis of two genome-wide association studies (FBrf0223922), the human gene XYLT1 is proposed as a candidate susceptibility locus for Alzheimer disease. XYLT1 encodes a xylosyltransferase enzyme that catalyzes the first step in biosynthesis of glycosaminoglycan chains. There is a single fly ortholog, oxt, for which RNAi-targeting constructs, and alleles caused by insertional mutagenesis have been generated. Dmel\oxt is also orthologous to the human gene XYLT2. XYLT1 is also implicated in the disease Desbuquois dysplasia 2 (MIM:615777) and as a modifying locus for Pseudoxanthoma elasticum (MIM:264800).
The XYLT1 gene has not been introduced into flies.
The fly ortholog oxt was tested for genetic interaction with a transgenically introduced mutational variant of the human tau gene (Hsap\MAPT): RNAi-mediated reduction in the expression of oxt was observed to enhance the phenotype associated with tau toxicity; overexpression in the eye reduces the tau toxicity phenotype. Genetic interactions of Dmel\oxt have been characterized; see the gene report for oxt.
[updated June 2016 by FlyBase; FBrf0222196]
Alzheimer disease (AD) is the most common form of progressive dementia in the elderly. [from MIM:104300; 2016.01.08]
Memory loss is the most common sign of Alzheimer disease. As the disorder progresses, some people with AD experience personality and behavioral changes; other common symptoms include agitation, restlessness, withdrawal, and loss of language skills. Total care is usually required during the advanced stages of the disease. Affected individuals usually survive 8 to 10 years after the appearance of symptoms, but the course of the disease can range from 1 to 25 years. Death usually results from pneumonia, malnutrition, or general body wasting. [from Genetics Home Reference, Alzheimer disease; 2016.01.08]
Alzheimer disease can be classified as early-onset or late-onset. The signs and symptoms of the early-onset form appear before age 65, while the late-onset form appears after age 65. The early-onset form is much less common than the late-onset form, accounting for less than 5 percent of all cases of Alzheimer disease. [from Genetics Home Reference, Alzheimer disease; 2016.01.08]
Locus identified as showing significant association with susceptibility to Alzheimer disease in an analysis of two genome-wide association studies (GWAS).
XYLT1 encodes a xylosyltransferase enzyme that catalyzes the first step in biosynthesis of glycosaminoglycan chains. [from Gene Cards, XYLT1; 2016.06.01]
Many to one: 2 human to 1 Drosophila; the fly gene oxt is orthologous to XYLT1 and XYLT2 in human.
High-scoring ortholog of human genes XYLT1 and XYLT2 (1 Drosophila to 2 human). Dmel\oxt shares 35-36% identity and 49-50% similarity with the human genes.
