Objective:

To describe the frequency and clinical profile of ASD-related symptoms and final clinical ASD diagnoses in children and adolescents with classical galactosemia.

Approach:

• Assessment Tools: Intellectual functioning was assessed using the Stanford–Binet Intelligence Scales, Fifth Edition. ASD symptoms were evaluated using the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID), Autism Spectrum Rating Scales (ASRS, parent version), and Autism Diagnostic Observation Schedule, Second Edition (ADOS-2), along with a comprehensive clinical assessment by a child and adolescent psychiatrist.

Key Findings:

• A clinical diagnosis of ASD was established in 36% of participants.
• Results indicating ASD symptoms were obtained in 56% of children using MINI-KID, 48% using ADOS-2, and 30% based on overall ASRS scores.
• Moderate negative correlations were found between IQ and ASD symptom severity, particularly in social communication and social-emotional reciprocity.
• Long-term manifestations like white matter abnormalities and osteopenia/osteoporosis were more frequent in children with ASD symptoms identified by MINI-KID.

Interpretation:

Children and adolescents with classical galactosemia frequently presented ASD-related social-communication difficulties, with a significant proportion meeting criteria for clinical ASD diagnosis.

Limitations:

• The study is limited by its small sample size of 50 participants.
• The lack of a national registry for classical galactosemia may affect data comprehensiveness.

Conclusion:

The study highlights the overlap of ASD symptoms in children with classical galactosemia, indicating a need for careful assessment in this population.