Toto is a primitive Indo-Bhutanese tribe residing in a small enclave called Totopara in the Jalpaiguri district of West Bengal, India. Toto culture and language is totally unique to the tribe, and is clearly distinguished from the neighboring Rajbongshis, Koch or the Bhutanese Sharchop tribes. Totos use to do consanguineous marriage and stay in the same locality even after marriage. Totos are becoming extinct since 1950. Total population of Totos are 1377 (smallest tribe of the world) and it is declining day by day. We noticed that their life span is very short (35-40 years). With a motive to investigate the reason behind it we started our work and got the answers of our queries. Almost 50% of them are carrier of beta Thalassemia, which is a genetic disease and are caused by the mutation of beta globin gene. The objectives of our study are,
To screen their whole population for Thalassemia (carrier / patient).
To increase the awareness level by arranging awareness program in that locality frequently through seminar, documentaries and discussions.
To make Totos understand about the ill fate of Thalassemia patients.
To control the birth of Thalassemic children, we are insisting them not to marry between two carriers.
Finally to confirm the mutation in globin gene by DNA analysis.
After awareness program, 3-4 ml of blood sample was collected from each Toto along with their written consent. On the spot inexpensive NESTROF (Naked Eye Single Tube Red Cell Osmotic Fragility) test was done. After returning to institute we use to do CBC (Complete Blood Count) followed by HPLC (High Performance Liquid Chromatography). DNA was isolated from those samples detected as carrier or patients using the protocol standardized in our lab. Mutation was detected by ARMS (Amplification Refractory Mutation System)–PCR.
Total individual already screened in the Totopara under the age limit 10- 35 years is 688. Number of Totos and Non-Totos are 628 and 60 respectively. From NESTROFT and CBC result it was revealed that different blood parameters e.g., MCV, MCH, RBC, RDW, Hb% etc of 71% Totos do not match with the normal value and found to be significantly altered. HPLC results show that 51% Totos are carrier of HbE and 20% of them are HbE homozygous. Whereas 97% non-Totos are found to be normal. DNA analysis by ARMS-PCR confirmed the result of HPLC. The percentage of HbE carrier and HbE homozygous is very high among Totos and this is the real cause of their early death. To protect this primitive tribe we have to restrict their marriage between two carriers. For Totos thalassemia carrier detection should be mandatory before marriage.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.