Why Friedreich’s ataxia spares some populations?
Friedreich’s ataxia, FRDA, destroys nerves and heart. Onset: 5-15 years. No cure. NIMS Hyderabad sees 1 case a month, mostly from consanguineous marriages.
A new study found FRDA is common in Europeans, West Asians, South Asians. Almost absent in Sub-Saharan Africans, East Asians, Southeast Asians.
Why? The FXN gene has two "normal" variants: short and long. Only short variants can expand and cause disease. Sub-Saharan Africans lack short variants. East Asians have them but rarely.
Analytically, this is evolution + culture. Consanguinity increases risk because it brings two bad copies together. In India, screening in high-risk communities can prevent cases.
Science here is not a new drug. It is geography of disease. Understanding why helps in counseling, early diagnosis, and targeted screening.
India must integrate genetics into primary health. We spend on ICU beds but ignore prevention. Knowing who is at risk is the cheapest cure.