Autism Spectrum Disorder in Two Unrelated Patients with Homozygous Variants in Either ALG8 or ALG11.

Background: Autism spectrum disorder (ASD) is used to describe individuals with a specific combination of disorders in social communication and repetitive behaviors, highly restricted interests, and/or sensory behavior that begin early in life. The prevalence of ASD has been increasing rapidly in recent years. Pathophysiology of ASDs remains still unclear; however, genetic defects and multifactorial causes have been reported to play an important role in genetic disorders. The prevalence of inborn errors of metabolism (IEM) reported among patients with ASD is 2-5%. The clinical presentation of congenital disorders of glycosylation (CDG) may be in the form of psychiatric disorder only.

Case study: Case 1: a 5-year-old female patient was admitted for investigation of ASD. She had a dysmorphic facial appearance, inverted nipples, abnormal fat distribution, ataxic gait, and autistic features. Her transferrin isoelectric focusing test was compatible with a type 1 CDG pattern. A homozygous variant in ALG8 gene revealed the diagnosis of ALG8-CDG (CDG Type 1H). Case 2: a 2-year-old male patient was admitted with complaints of ASD for investigation of an underlying IEM due to speech delay. Physical examination revealed hypertelorism, small hands, and autistic behavior. Transferrin isoelectric focusing test was also found normal. As a result of the WES, a homozygous variant was detected in ALG11 confirming the diagnosis of CDG type 1p.

Conclusion: CDG should also be considered in the differential diagnosis of autistic patients with dysmorphic findings. The aim of our study was to emphasize that autism should be listed among the neurological findings of CDG.