Author: Saviour P, Ramachandra NB
Department of Studies in Zoology, University of Mysore, Manasagangothri, Mysore-570006, India
Ramachandra N B
Human genetics Laboratory, Department of Studies in Zoology, University of Mysore
Acquisition of language has become ever more important in this information age. Most children acquire it naturally in a sequence of listening, speaking, reading and writing. Failure in any of these processes may lead to life long socioeconomic and mental health consequences.
There are many causes of language disability; the most common is developmental dyslexia, which is defined as difficulty in learning to read and spell despite adequate education, intelligence, sociocultural opportunities and without any obvious sensory deficits.
It accounts for 80% of learning disabilities. The phenotype of dyslexia is complex and different phenotype dimensions can be distinguished. Although multiple etiologies are proposed for the this complex trait exact cause still remains unknown but substantial evidence from genetic and neurobiological studies suggest that dyslexia is a disorder which is influenced by genetic factors and the underlying deficit is in the language areas of the brain.
Though dyslexia is a major educational problem, no much study has been done on the family patterns of dyslexia in India. There is a great dearth of proper statistical data to show the incidence of dyslexia in Indian population. Here we report the patterns of genetic transmission of dyslexia in 23 Indian families.
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.
How to cite this article:
Saviour P, Ramachandra NB. Modes of genetic transmission of dyslexia in south Indian families. Indian J Hum Genet 2005;11:135-139
How to cite the URL:
Saviour P, Ramachandra NB. Modes of genetic transmission of dyslexia in south Indian families. Indian J Hum Genet [serial online] 2005 [cited 2006 May 16];11:135-139. Available from: http://www.ijhg.com/article.asp?issn=0971-6866;year=2005;volume=11;issue...