HLA Polymorphism in Regressive and Non-Regressive Autism: A Preliminary Study.

Area of Science:

• Immunogenetics
• Neurodevelopmental disorders
• Autism Spectrum Disorder (ASD) research

Background:

• Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental condition.
• A subset of ASD cases (10-30%) exhibits regression, characterized by loss of language and social skills around 18-30 months.
• Immune dysfunctions, including inflammation and autoimmunity, are implicated as potential risk factors in regressive ASD.

Purpose of the Study:

• To investigate the distribution of Human Leukocyte Antigen (HLA) Class I and Class II haplotypes in children with ASD.
• To determine if specific HLA haplotypes are associated with the regressive subtype of ASD.
• To explore the potential role of HLA polymorphism in the immune-related aspects of regressive ASD.

Main Methods:

• Analysis of HLA Class I and Class II haplotype distribution in 131 children diagnosed with ASD (DSM-IV-TR criteria).
• Comparison of haplotype frequencies between non-regressive ASD, regressive ASD, and healthy controls.
• Statistical analysis to identify significant associations between HLA haplotypes and ASD subtypes.

Main Results:

• The HLA-DPA1*01-DPB1*04 sub-haplotype was found in 63% of non-regressive ASD patients versus 43% of regressive ASD patients (Pc=0.02).
• This specific HLA haplotype was also more represented in healthy controls compared to patients with common nonpsychiatric autoimmune disorders.
• These findings suggest a potential protective role for HLA-DPA1*01-DPB1*04 against regression in ASD.

Conclusions:

• HLA polymorphism may be involved in the pathogenesis of regressive ASD.
• The HLA-DPA1*01-DPB1*04 sub-haplotype might confer a protective effect against the development of regression in individuals with ASD.
• This association suggests a link between HLA-mediated immune processes and regressive ASD phenotypes.