Background: Dyslexia is a major educational problem, but the studies
on genetics of dyslexia are very limited in India. There is a great
dearth of proper statistical data to show the incidence of dyslexia in
Indian population. More over inheritance pattern of dyslexia is not
well established in our population. Aims & Objective: To
establish the inheritance pattern of dyslexia in 23 selected families.
Materials and Methods: We have ascertained 23 dyslexic probands and
their families from the state of Karnataka. Individuals with above 8
years of age, normal performance intelligence quotient (>85) and
remarkable deviation in reading and writing skills compared to
chronological age were considered for the study. Based on the genetic
registry pedigrees of the families were constructed. Results: Based
on the affectedness, the dyslexia phenotypes were classified into four
types: severe reading spelling deficit, mild reading spelling deficit,
severe spelling deficit and mild spelling deficit. Severe dyslexia
phenotypes were more frequent than mild phenotypes. Mild spelling
deficits were better compensated than the other types. It was found
that autosomal dominant inheritance pattern of dyslexia was more
prevalent than autosomal recessive and sporadic pattern in the present
study. Conclusion: Family history of dyslexia is a consistent risk
factor; therefore this knowledge can be applied to the prevention and
remediation of dyslexia