FB2026_01 , released March 12, 2026
FB2026_01 , released March 12, 2026
Human Disease Model Report: intellectual disability, autosomal recessive 46
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General Information
Name
intellectual disability, autosomal recessive 46
FlyBase ID
FBhh0000248
Overview

This report describes intellectual disability, autosomal recessive 46; an alternative designation of this disease is 'mental retardation, autosomal recessive 46' (MRT46). The human gene implicated in this disease is NDST1, which catalyzes both the N-deacetylation and the N-sulfation of heparan sulfate glycosaminoglycans; it is a transmembrane protein that resides in the Golgi apparatus. There is a single fly ortholog, sfl, for which loss-of-function alleles, RNAi-targeting constructs and an allele caused by insertional mutagenesis have been generated. Dmel\sfl is also orthologous to human genes NDST2, NDST3, AND NDST4. The NDST1 gene has also been implicated in a recent GWAS study with non-obstructive azoospermia (FBhh0000239).

The NDST1 gene has not been introduced into flies.

In Drosophila, systemic knockdown of sfl typically results in lethality during the pupal stage. Assessments of larval phenotypes reveal locomotor defects and abnormalities in synaptic physiology and morphology. Genetic interactions of Dmel\sfl have been characterized; see the gene report for sfl.

[updated Apr. 2016 by FlyBase; FBrf0222196]

Disease Summary Information
Parent Disease Summary: intellectual disability, autosomal recessive
Symptoms and phenotype

Intellectual disability is characterized by impairments in intellectual functioning and adaptive behavior; symptoms must be present before a child becomes 18 years old (http://medical-dictionary.thefreedictionary.com/mental+retardation; 2016.01.19).

Intellectual disability can be subdivided into syndromic forms, characterized by cognitive impairment accompanied by dysmorphic features, malformations or neurological abnormalities, and nonsyndromic forms, characterized by cognitive impairment without additional features (Basel-Vanagaite, 2008; DOI: 10.1002/9780470015902.a0021454).

Specific Disease Summary: intellectual disability, autosomal recessive 46
OMIM report

[INTELLECTUAL DEVELOPMENTAL DISORDER, AUTOSOMAL RECESSIVE 46; MRT46](https://omim.org/entry/616116)

Human gene(s) implicated

[N-DEACETYLASE/N-SULFOTRANSFERASE 1; NDST1](https://omim.org/entry/600853)

Symptoms and phenotype

Patients from a small number of families have been characterized. All had delayed psychomotor development apparent from infancy or early childhood with delayed or absent expressive speech; most patients had hypotonia; some had therapy-responsive seizures. [from MIM:616116]

Genetics

Autosomal recessive mental retardation 46 (MRT46) is caused by homozygous mutation in the NDST1 gene, exhibiting an autosomal-recessive mode of inheritance. [from MIM:616116]

Cellular phenotype and pathology
Molecular information

NDST1 is a member of the heparan sulfate/heparin GlcNAc N-deacetylase/N-sulfotransferase family, involved in the biosynthesis of heparan sulfate proteoglycans. The NDST1 enzyme is a type II transmembrane protein that resides in the Golgi apparatus. [from Gene Cards, NDST1; 2016.04.07]

External links
Disease synonyms
intellectual disability, autosomal recessive 46
mental retardation, autosomal recessive 46
MRT46
Ortholog Information
Human gene(s) in FlyBase
    Human gene (HGNC)
    D. melanogaster ortholog (based on DIOPT)
    Comments on ortholog(s)

    Many to one: 4 human to 1 Drosophila; additional high-scoring human orthologous genes are NDST2, NDST3, and NDST4; one low-scoring ortholog also exists.

    Other mammalian ortholog(s) used
      D. melanogaster Gene Information (1)
      Gene Snapshot
      sulfateless sfl encodes a heparan sulfate-glucosamine N-sulfotransferase that catalyzes both the N-deacetylation and the N-sulfation of N-acetyl-glucosamine (GlcNAc) of the heparan sulfate glycosaminoglycan chain. It is involved in the first step in heparan sulfate modification and is required for subsequent sulfotransferase reactions at the 2-O position of iduronate or glucuronate, and the 6-O-position of glucosamine. [Date last reviewed: 2024-12-19]
      Gene Groups / Pathways
      Comments on ortholog(s)

      Ortholog of human genes NDST1, NDST2, NDST3, AND NDST4 (1 Drosophila to 4 human). Dmel\sfl shares 53-55% identity and 70-71% 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 (7 groups)
        RNA-protein
        Interacting group
        Assay
        References
        anti tag coimmunoprecipitation, nucleic acid uv cross-linking assay, reverse transcription pcr, quantitative reverse transcription pcr
        anti tag coimmunoprecipitation, nucleic acid uv cross-linking assay, quantitative reverse transcription pcr, reverse transcription pcr
        anti tag coimmunoprecipitation, nucleic acid uv cross-linking assay, reverse transcription pcr, quantitative reverse transcription pcr
        anti tag coimmunoprecipitation, nucleic acid uv cross-linking assay, quantitative reverse transcription pcr
        anti tag coimmunoprecipitation, nucleic acid uv cross-linking assay, reverse transcription pcr, quantitative reverse transcription pcr
        anti tag coimmunoprecipitation, nucleic acid uv cross-linking assay, quantitative reverse transcription pcr, reverse transcription pcr
        anti tag coimmunoprecipitation, nucleic acid uv cross-linking assay, quantitative reverse transcription pcr
        Alleles Reported to Model Human Disease (Disease Ontology) (5 alleles)
        Models Based on Experimental Evidence ( 4 )
        Modifiers Based on Experimental Evidence ( 3 )
        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
        Related mammalian, viral, bacterial, or synthetic 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 (5)