The February 2005 issue of the Indian pediatrics reported the first study on the genetic polymorphisms of Attention Deficit Hyperactivity Disorder (ADHD) in the Indian subcontinent(1). ADHD is a childhood disorder which has been inadequately studied in the region. There is a dearth of baseline literature and as a result many children remain undiagnosed and fall to the injustices of the illiterate majority. Bhaduri, et al. have made a great contribution by opening new avenues in the study of ADHD in the Asian region. This area definitely needs more exploration.

We would like to make some suggestions. It was interesting to observe the differences in Taq transmission specific to our population. We must however, remain cognizant of the strong component of consanguinity while interpreting these results. Intra family marriages are extremely common in certain tribes and ethnic communities in this part of the world. Therefore, it is quite plausible that genes for certain traits including cognitive characteristics get concentrated in families. A multivariate analysis where the family history of ADHD is considered would thus be a vital inclusion in such a study design.

It has been seen in preliminary studies done at our institution and also abroad that a huge proportion of ADHD cases exist concurrently with reading disorders such as dyslexia. The degree of overlap between ADHD and dyslexia has been reported to be 35%(2). The combined subtype of ADHD is one of the most common ones as shown by Indian and Pakistani data(3-4). The co-morbidity of ADHD and dyslexia is so common that diagnosis of either disorder should involve assessment for the other. All children with ADHD in this study should ideally have undergone a psychometric assessment to evaluate for the presence of a learning disability. Though Intelligence Quotient (IQ) evaluation was included in the initial evaluation of these subjects, evidence to show that IQ scores playa major role in identifying children with learning disability is limited. The children with co-morbidity could therefore have been a part of the exclusion criteria or could be separately analyzed for atypical or new polymorphisms. The tools used for screening of these disorders need to be suited and validated according to the local languages. A multilingual India creates even more problems in finding a universal tool for screening such children(5). Incorporation of the above suggestions in a study design will help in a better understanding of ADHD.

Omar Aftab,
Fawad Aslam,
Room 212, Male Hostel,
Aga Khan University,
Stadium Road,
Karachi 748 00, Pakistan.
E-mail: [email protected]