Consanguinity of parents of children with PDD: comparison between patients with and without associated medical conditions

Background:

Estimates of consanguineous marriages are relatively high in Tunisia (30 to 34%), leading to a high rate of genetic disorders. Therefore, study of consanguinity may be relevant for the understanding of the genetic transmission of PDD.

Objectives:

To estimate the prevalence of consanguinity among parents of children with Pervasive Developmental Disorders, and to compare it in two groups: children with and without proved comorbid neurological or genetic pathology.

Methods:

Genealogic evaluation have been conducted for families of all consecutive patients of the child psychiatry clinic at the University Hospital F. Bourguiba, Monastir (Tunisia), over years 2003 to 2007, who received a diagnosis of PDD according to DSM IV criteria and to the scales CARS-T and/or  PDD-MRS, and for whom a standard neurological and genetic assessment has been obtained (audiometry, EEG, brain imagery, chromosomal formula, screening for innate metabolic disorders and research for fragile X mutations when indicated) (N=186)

Results:

Overall consanguinity rate was 32,8%. It was respectively 44,6% and  28,7% for patients with and without established comorbid medical conditions. No major differences were found in familial histories of mental or language delays between the two groups.

Conclusions:

Parental consanguinity may lead to a higher heritability of pathological traits in neurodevelopmental disorders, and hence to more severe clinical pictures.