Related Experiment Videos
Clinical and genetic relationships between autism-pervasive developmental disorder and Tourette syndrome: a study of
1Department of Medical Genetics, City of Hope National Medical Center, Duarte, CA 91010.
Insights
Children with autism or pervasive developmental disorder (PDD) and Tourette syndrome (TS) may share genetic links. This study suggests a common genetic basis for PDD and TS, explaining shared symptoms and family patterns.
Area of Science:
- Neurodevelopmental disorders
- Genetics
- Psychiatry
Background:
- Autism or PDD and Tourette Syndrome (TS) share overlapping symptoms.
- Previous reports documented PDD patients developing TS.
Observation:
- This study describes 16 new cases of PDD evolving into TS (PDD-TS).
- Three families showed a TS proband with an autistic relative.
- Relatives of PDD-TS patients exhibited high rates of alcoholism, drug abuse, and behavioral disorders, similar to relatives of TS-only individuals.
Findings:
- A significant genetic and neuropathologic relationship is proposed between PDD and TS.
- The genetic defect in TS may involve tryptophan oxygenase, with a semidominant/semirecessive inheritance pattern.
- Some PDD types may share the same genetic inheritance pattern and gene as TS.
Implications:
- This shared genetic basis could explain symptom similarities and PDD-TS evolution.
- It may also account for apparent recessive PDD inheritance and behavioral issues in relatives.
- Further research into serotonin abnormalities in PDD and TS is warranted.
Abstract:
Children with autism or pervasive developmental disorder (PDD) and Tourette syndrome (TS) share a number of symptoms. Forty-one cases have been reported in which PDD patients subsequently developed TS. We term this PDD----TS. We describe an additional 16 such patients plus 3 families where a close relative of a TS proband had autism. There was a high frequency of alcoholism, drug abuse, obsessive-compulsive, and other behavior disorders in the relatives of these patients. This frequency was virtually identical to that observed in relatives of individuals with TS only. We suggest there is an intimate genetic, neuropathologic relatedness between some cases of PDD and TS. Many observations have led us to suggest that the genetic defect in TS may be a mutation of tryptophan oxygenase and that TS is inherited as a semidominant semirecessive trait, i.e., homozygosity for a common gene which shows some expression in the heterozygous state. We propose that some types of PDD are inherited in the same fashion and by the same gene. This would explain the similarity of symptoms, frequent evolution of PDD into TS, the apparent recessive inheritance of PDD despite no increase in consanguinity, the high frequency of behavior problems in the relatives of PDD----TS patients and the serotonin abnormalities.