Write an account on the prevalence of sickle cell disease among the tribal populations of India. What are the initiatives undertaken by the affected states to tackle with this disease? (Answer in 250 words)

- Write an account on the prevalence of sickle cell disease among the tribal populations of India. What are the initiatives undertaken by the affected states to tackle with this disease? (Answer in 250 words)
Introduction
Sickle cell disease is India's commonest inherited disorder and is concentrated in the tribal belt, where it persists because the same variant protected against malaria.

Body
1. The genetic basis: a single base substitution in the beta-globin gene replaces glutamic acid with valine at the sixth position, producing haemoglobin S. When deoxygenated it polymerises and distorts the red cell, giving haemolytic anaemia and vaso-occlusive crises in homozygotes. Heterozygotes are protected against falciparum malaria, so in a malarious tribal environment the allele is maintained as a balanced polymorphism, and endogamy raises the frequency of homozygotes.
2. Prevalence and distribution: first reported in India by Lehmann and Cutbush in 1952 among the Nilgiri hill tribes. Carrier rates range from under one per cent to more than thirty, commonly ten to twenty per cent among the Gond, Bhil, Madia, Baiga, Sahariya and Pardhan. Three belts are recognised — central India from Gujarat and Rajasthan through Madhya Pradesh, Chhattisgarh, Maharashtra and Odisha to Jharkhand, the Nilgiri and Western Ghats south, and pockets in the east. It is not confined to tribes. The Indian haplotype carries higher foetal haemoglobin and milder disease than African ones.
3. State and national initiatives: Gujarat's control programme from 2006 pioneered screening with carrier cards and counselling before marriage; Madhya Pradesh, Maharashtra, Chhattisgarh and Odisha followed, Odisha with an institute at Burla. The National Sickle Cell Anaemia Elimination Mission, launched in 2023, aims to screen the tribal population under forty across seventeen states and eliminate the disease as a public health problem by 2047, with hydroxyurea, folic acid and disability certification.
4. The limitations: screening far outruns treatment and follow-up.

Conclusion
Carrier cards without counselling stigmatise, and hydroxyurea supply and referral remain weak. The mission's targets measure screening, not survival.