"Everyone Is A Cousin" In This Village. Courtesy: A Rare Genetic Condition

NDTV

12-05-2025

New Delhi:
A small village in Brazil is afflicted with Spoan syndrome, a rare hereditary illness that weakens the body over time by affecting the nervous system. A 2010 study, headed by geneticist and biologist Silvana Santos, found that more than 30 per cent of couples in Serrinha dos Pintos were related.
Spoan syndrome occurs only when both parents carry the mutated gene, the BBC reported.
Ms Santos visited Serrinha dos Pintos, a secluded community tucked away in the northern Brazilian hills, more than 20 years ago.
The village, with less than 5,000 residents, has long struggled with a perplexing medical riddle. Several children were reportedly losing their ability to walk, and families had no idea why.
Ms Santos was first encouraged to visit the area by her Brazilian neighbours, many of whom were from Serrinha and were married into their extended families. They said many in their homeland couldn't walk, and nobody could tell why.
She called Serrinha "a world of its own" when she eventually visited, citing both its natural beauty and its close-knit community.
According to Ms Santos, intermarriage between cousins was common in the town, more so than in most other parts of Brazil, because of its remote location and low rate of inward migration.
Ms Santos reportedly travelled 2,000 kilometres between Sao Paulo and Serrinha, gathering DNA samples from people's doors, having coffee with families, and finally establishing the link.
The study found that one-third of them had at least one child with Spoan syndrome. Although the numbers vary by nation, cousin marriages account for around 10 per cent of marriages worldwide. It ranges from 1 to 4 per cent in Brazil.
The first scientific study on the Spoan syndrome was published in 2005 by Santos' team. The condition is caused by a small chromosomal defect that causes brain cells to overproduce a crucial protein.
According to experts, the likelihood of passing on rare genetic abnormalities nearly doubles, even if the majority of cousins' children are born healthy.
Ms Santos further claimed that strong European ancestry, including traces of Dutch, Portuguese, and Sephardic Jewish backgrounds, was found in the genetic sequencing of Spoan patients.
Ms Santos' pioneering effort later won her a place in the BBC's list of the 100 most influential women in 2024, and it was the first time the disease was ever recognised worldwide.
Although there is no cure for the Spoan syndrome, Ms Santos' efforts have changed how the public views the condition.