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General Information
Name
Alzheimer disease, susceptibility to (postulated), XYLT1-related
FlyBase ID
FBhh0000283
Disease Ontology Term
Parent Disease
OMIM
Overview

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 (OMIM:615777) and as a modifying locus for Pseudoxanthoma elasticum (OMIM: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]

Disease Summary Information
Parent Disease Summary: Alzheimer disease
Symptoms and phenotype

Alzheimer disease (AD) is the most common form of progressive dementia in the elderly. [from OMIM: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]

Specific Disease Summary: Alzheimer disease, susceptibility to (postulated), XYLT1-related
OMIM report
Human gene(s) implicated
Symptoms and phenotype
Genetics

Locus identified as showing significant association with susceptibility to Alzheimer disease in an analysis of two genome-wide association studies (GWAS).

Cellular phenotype and pathology
Molecular information

XYLT1 encodes a xylosyltransferase enzyme that catalyzes the first step in biosynthesis of glycosaminoglycan chains. [from Gene Cards, XYLT1; 2016.06.01]

External links
Disease synonyms
Ortholog Information
Human gene(s) in FlyBase
    Human gene (HGNC)
    D. melanogaster ortholog (based on DIOPT)
    Comments on ortholog(s)

    Many to one: 2 human to 1 Drosophila; the fly gene oxt is orthologous to XYLT1 and XYLT2 in human.

    Other mammalian ortholog(s) used
      D. melanogaster Gene Information (1)
      Gene Snapshot
      peptide O-xylosyltransferase (oxt) encodes an enzyme that catalyzes the first xylose of the linkage region of glycosaminoglycan (GAG). Through GAG synthesis, the product of oxt is involved in several signaling pathways mediated by GAGs in development. [Date last reviewed: 2019-03-14]
      Gene Groups / Pathways
      Comments on ortholog(s)

      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.

      Orthologs and Alignments from DRSC
      DIOPT - DRSC Integrative Ortholog Prediction Tool - Click the link below to search for orthologs in Humans
      Other Genes Used: Viral, Bacterial, Synthetic (0)
        Summary of Physical Interactions (0 groups)
        Alleles Reported to Model Human Disease (Disease Ontology) (2 alleles)
        Models Based on Experimental Evidence ( 0 )
        Allele
        Disease
        Evidence
        References
        Modifiers Based on Experimental Evidence ( 2 )
        Allele
        Disease
        Interaction
        References
        Alleles Representing Disease-Implicated Variants
        Genetic Tools, Stocks and Reagents
        Sources of Stocks
        Contact lab of origin for a reagent not available from a public stock center.
        Bloomington Stock Center Disease Page
        Selected mammalian transgenes
        Allele
        Transgene
        Publicly Available Stocks
        Selected Drosophila transgenes
        Allele
        Transgene
        Publicly Available Stocks
        RNAi constructs available
        Allele
        Transgene
        Publicly Available Stocks
        Selected Drosophila classical alleles
        Allele
        Allele class
        Mutagen
        Publicly Available Stocks
        References (4)