Rare condition in the city of Brazil popular for the marriage of cousin

Before Silvana Santos arrived in the small town of Serrinha Dos Pintos more than 20 years ago, residents had no idea why so many local children had lost the ability to walk.

The remote city in northeast Brazil is the home of less than 5,000 people, and is where biologist and geneticist Santos identified and mentioned a previously unknown state: Spoan Syndrome.

Caused by a genetic mutation, the syndrome influences the nervous system, so that the body is gradually weakened. It only appears when the changed gene of both parents is inherited.

Santos’ research was the first time that the disease had been described all over the world. For this and later work, she was named one of the 100 most influential women of the BBC in 2024.

Before Santos arrived, families had no explanation for the disease that affects their children. Nowadays, residents talk about Spoan and Genetics confidently.

“She gave us a diagnosis that we never had. After the study, help came: people, financing, wheelchairs,” says Marquinhos, one of the patients.

Where Santos comes from in São Paulo, the largest and richest city in Brazil, many of her neighbors were members of the same extensive family originally from Serrinha. Many of them were cousins ​​of varying degrees, married to each other.

They told Santos that many people could not walk in their hometown, but that nobody knew why.

One of the daughters of the neighbors, Zirlândia, suffered from a debilitating state: as a child, her eyes moved involuntarily and over time she lost strength in her limbs and had to use a wheelchair, which needed help with even the simplest tasks.

Years of research would lead Santos and a research team to identify it as symptoms of Spoan Syndrome.

They would find 82 other cases worldwide.

At the invitation of her neighbors, Santos visited Serrinha on vacation. She describes her arrival when stepping in “a world of its own” – not only because of the lush landscape and the mountain views, but also because of what seemed to be a remarkable social coincidence.

The more she walked and spoke with the locals, the more she was about how common marriages were between cousins.

Serrinha’s geographical insulation and little inner migration mean that many of the population are related, making the marriage between cousins ​​much more likely and more social acceptable.

Worldwide, marriages between family members were estimated at around 10% in the early years 2010. More recent data shows that the rate varies greatly, from more than 50% in countries such as Pakistan, to 1-4% in Brazil and less than 1% in the US and Russia. Most children born in couples and nieces are healthy, experts say.

But these marriages do run a higher risk of a harmful genetic mutation that is passed on by the family.

“If a pair is not related, the chance of a child with a rare genetic disorder or disability is about 2-3%. For cousins, the risk is up to 5-6% per pregnancy,” explains geneticist Luzivan Costa trip of Brazili’s federal university of Rio Grande do Sul.

A 2010 study under the leadership of Santos showed that more than 30% of the couples were related in Serrinha, and one third of them had at least one child with a disability.

Santos wanted to find a diagnosis for the people of Serrinha and she started planning a detailed genetic investigation, for which several journeys were needed and eventually led to her move to the region.

She drove the 2,000 km to and from São Paulo many times in the early years of her research. She collected DNA samples from door to door, talked to the locals during coffee and collected family stories, trying to find the mutation that causes the disease.

What should be of fieldwork for three months changed in years of dedication.

It all led to the publication in 2005 of the team’s study, which revealed the existence of Spoan in the Brazilian hinterland.

The Santos team discovered that the mutation contains the loss of a small fragment of a chromosome, so that a gene over produces an important protein in brain cells.

“They said it came from Maximiano, a womanizer in our family,” recalls Farmer Lolô, whose daughter Rejane has Spoan.

Lolô, now 83, never married his cousin and never left Serrinha. He still takes care of cattle and trusts family to take care of Rejane, who is struggling with daily tasks.

But the genetic mutation behind Spoan is much older than the legend of the old Maximiano: it probably arrived more than 500 years ago with early European settlers in northeast Brazil.

“Sequencing studies show strong European descent in patients, in support of data from the Portuguese, Dutch and Sephardic Jewish presence in the region,” says Santos.

The theory got strength after two Spoan cases were found in Egypt, and further studies showed that the Egyptian cases also shared European descent, pointing to a common origin on the Iberian peninsula.

“It probably came with related Sephardic Jews or Moors who fled the Inquisition,” says Santos. She believes that there can be more cases worldwide, especially in Portugal.

Although little progress has been made in the direction of a remedy, following patients has brought some change. Rejane remembers how people used to be called “cripples”. Now it is just said that they have Spoan.

Wheelchairs not only brought independence, but also helped prevent malformations – in the past many with the condition were simply left in bed or on the floor.

As Spoan progresses, physical restrictions aggravate with age and with 50, almost all patients become completely dependent on caregivers.

This is the case for the children of Inés, who are among the oldest in Serrinha. Chiquinho, 59, can no longer speak, and Marquinhos, 46, has limited communication skills.

“It is difficult to have a ‘special’ child. We keep the same thing, but we suffer for them,” says Inés, who is married to a second cousin.

Larissa Queiroz, 25, The niece of Chiquinho and Marquinho, also married a distant family member. She and her husband, Saulo, only discovered their common ancestor after a few months of dating.

“In Serrinha Dos Pintos we are deep on the inside. We are related to everyone,” she says.

Couples such as Larissa and Saulo are the focus of a new research project in which Santos is also involved. Supported by the Brazilian Ministry of Health, the 5,000 couples will screen on genes related to serious recessive diseases.

The goal is not to stop cousin marriages, but to help couples understand their genetic risks, says Santos. Now a university professor, she also leads a Genetics Education Center and works to expand testing in northeast Brazil.

Although she no longer lives in Serrinha Dos Pintos, every visit feels like coming home.

“It’s as if Santos is family,” says Inés.