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Updated: Jul 27, 2026
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Paradigms for Behavioral Assessment in Drosophila Model of Autism Spectrum Disorder
Published on: September 6, 2024
Autism and the X chromosome. Multipoint sib-pair analysis
J Hallmayer1, J M Hebert, D Spiker
1Department of Psychiatry and Behavioral Sciences, Nancy Pritzker Laboratory of Developmental and Molecular Neurobiology, Stanford University, Calif, USA.
Archives of General Psychiatry
|November 1, 1996
Summary
Genetic factors contribute to autism, but inheritance is unclear. This study found no strong evidence for X-linked genes causing autism, though smaller effects remain possible.
Area of Science:
- Genetics
- Neurodevelopmental Disorders
- Human Genetics
Background:
- Genetic factors are significant in autism etiology.
- The inheritance pattern of autism remains largely unknown.
- Higher autism incidence in males suggests potential X chromosome involvement.
Purpose of the Study:
- To investigate the role of X-linked genes in autism inheritance.
- To identify specific regions on the X chromosome linked to autism.
Main Methods:
- Utilized data from 38 multiplex autism families.
- Conducted multipoint sib-pair linkage analysis on the X chromosome.
- Assessed linkage using risk ratio (lambda xs) parameter and exclusion mapping.
Main Results:
- The entire X chromosome was excluded for a risk ratio (lambda xs) of 4.
- Exclusion ability decreased with smaller lambda xs values.
- A maximum lod score of 1.24 was observed at locus DXS424 for lambda xs = 1.5.
Conclusions:
- Moderate to strong gene effects on the X chromosome causing autism were excluded.
- Smaller gene effects (lambda xs < 4) could not be ruled out.
- A potential small-effect gene between DXS453 and DXS1001 was not excluded.
Related Concept Videos
01:35Pedigree Analysis
Overview
01:58X-Inactivation
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results.
02:32X and Y Chromosomes
Among mammals, the gender of an organism is determined by the sex chromosomes. Humans have two sex chromosomes, X and Y. Every human diploid cell has 22 pairs of autosomes and one pair of sex chromosomes. A human female has two X chromosomes, while a male has one X chromosome and one Y chromosome.
The germline cells such as egg and sperm cells carry only half the number of chromosomes, i.e., 22 autosomes and one sex chromosome. All eggs have an X chromosome, while sperm cells can carry an X or...
The germline cells such as egg and sperm cells carry only half the number of chromosomes, i.e., 22 autosomes and one sex chromosome. All eggs have an X chromosome, while sperm cells can carry an X or...
02:45The Ratio of X Chromosome to Autosomes
In most organisms, sex is determined by the ratio of X and Y chromosomes. However, in some organisms, such as Drosophila and C.elegans, sex is determined by the ratio of the number of X chromosomes to the number of sets of autosomes. The Y chromosome in Drosophila is active but does not determine sex. It contains genes responsible for the production of sperms in adult flies.
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
Normal male Drosophila has a ratio of one X chromosome to two sets of autosomes. In contrast, normal female Drosophila...
01:58X-inactivation
The human X chromosome contains over ten times the number of genes as in the Y chromosome. Since males have only one X chromosome, and females have two, one might expect females to produce twice as many of the proteins, with undesirable results.
01:19Autism Spectrum Disorder
Autism spectrum disorder (ASD) is a neurodevelopmental condition marked by persistent deficits in social communication and interaction alongside restrictive and repetitive behaviors or interests. ASD is sometimes accompanied by intellectual impairment.
These core symptoms manifest differently among individuals, ranging from mild to severe. The disorder's complexity extends beyond its clinical presentation, encompassing a diverse range of biological, cognitive, and sociocultural influences.
These core symptoms manifest differently among individuals, ranging from mild to severe. The disorder's complexity extends beyond its clinical presentation, encompassing a diverse range of biological, cognitive, and sociocultural influences.