Related Experiment Videos
Rett syndrome: potential gene sources--phenotypical variability
H O Akesson1, J Wahlström, I W Engerström
1Department of Psychiatry, Sahlgrenska Hospital, Göteborg, Sweden.
Clinical Genetics
|October 1, 1995
Summary
Swedish Rett syndrome (RS) shows a strong common ancestry, with many affected females tracing back to the same homesteads. This genetic link may explain disease variants and transmission patterns.
Area of Science:
- Genetics
- Neurology
- Medical History
Background:
- Previous studies indicated a common ancestral origin for classical Swedish Rett syndrome (RS) females.
- A significant percentage of RS patients originated from the same homesteads generations ago.
Purpose of the Study:
- To perform an a priori test of the initial genealogical findings in Swedish Rett syndrome.
- To investigate the prevalence of common ancestry and its potential impact on RS phenotypical variability.
Main Methods:
- Genealogical tracing of an additional 20 consecutively identified Swedish Rett syndrome (RS) females.
- Analysis of ancestral origins, including homestead and geographic "Rett areas."
- Assessment of consanguineous marriage rates among grandparents of RS patients.
Main Results:
- 53% of the 19 RS females originated from defined "Rett areas," with 58% traceable to the same homestead.
- Two distinct clusters of three RS females each shared common ancestors from two couples.
- Consanguineous marriages were significantly more frequent (11%) in the RS patient group compared to the general Swedish population (1%).
Conclusions:
- The study confirms the high rate of common ancestry among Swedish Rett syndrome (RS) females.
- Phenotypical variability in RS is observed among interrelated females, suggesting a genetic component.
- Genealogical data suggest a possible transmission model involving premutations that can lead to full mutations over generations, potentially influenced by homozygous parental premutations.