More than twenty years ago, biologist and geneticist Silvana Santos embarked on a life-changing journey to Serrinha dos Pintos, a secluded hillside town in northeastern Brazil. Home to fewer than 5,000 people, the town had long puzzled residents and doctors alike—many children were mysteriously losing the ability to walk. There were no answers, only growing concerns.
Santos, who lived in São Paulo at the time, became intrigued after hearing alarming stories from her neighbours—many of whom had family ties to Serrinha and marriages within extended families. Their accounts of children back home affected by an unknown illness sparked her initial interest.
Discovering a New Genetic Disorder: Spoan Syndrome
That visit eventually led to a groundbreaking medical discovery. Santos identified and named Spoan syndrome, a previously undocumented genetic disorder that affects the nervous system. The disease only manifests when a child inherits the same mutated gene from both parents.
Her findings not only brought global recognition, earning her a spot on the BBC’s list of 100 most influential women in 2024—but also changed lives in Serrinha forever.
“She gave us a diagnosis we never had. After the research, help came: people, funding, wheelchairs,” said Marquinhos, one of the many patients diagnosed with Spoan.
Cousin Marriages and the Genetics Connection
Santos’s research began in São Paulo’s neighbourhoods, where she observed that many of her Serrinha-born neighbours had married their cousins. One such person, Zirlândia, had uncontrollable eye movements and later lost motor control, requiring full-time assistance.
Encouraged by these stories, Santos visited Serrinha and found that inter-family marriages were widespread, largely due to the town’s isolation and limited migration. A 2010 study she led revealed that over 30% of couples in Serrinha were related, and nearly a third of them had at least one child with a disability.
While global studies estimate about 10% of marriages occur between relatives, the rates vary widely—from over 50% in Pakistan to around 1–4% in Brazil. According to geneticist Luzivan Costa Reis, “If a couple is unrelated, the chance of having a child with a rare genetic disorder or disability is about 2–3%. For cousins, the risk rises to 5–6% per pregnancy.”
Years of Dedication and a Breakthrough
Santos’s short research trip turned into years of persistent fieldwork. She drove nearly 2,000 km between São Paulo and Serrinha multiple times, collecting DNA, talking with families, and building genealogies over coffee chats.
Her hard work culminated in a 2005 study that identified Spoan syndrome as a condition caused by the loss of a small chromosomal fragment. This genetic defect leads to the overproduction of a protein in brain cells, disrupting normal neurological function.
“They said it came from Maximiano, a womaniser in our family,” recalled Lolô, a farmer whose daughter, Rejane, lives with the syndrome.
Now 83, Lolô believes the gene may have older origins, something Santos’s genetic analysis supports. She found links between affected individuals in Brazil and European ancestry, likely tracing the mutation back to Sephardic Jews or Moors fleeing persecution on the Iberian Peninsula over 500 years ago. Supporting her theory, two identical cases were found in Egypt, sharing similar European lineage.
A New Era of Awareness and Action
Although no cure exists yet, Santos’s work has transformed Serrinha. Awareness about genetics has replaced stigma. Many patients, once confined to beds or the floor, now have wheelchairs and medical support.
Spoan syndrome continues to affect families, `patients often become fully dependent by age 50. Inés, mother to Chiquinho and Marquinhos, shared her heartache: “It’s hard to have a ‘special’ child. We love them the same, but we suffer for them.”
Her niece, Larissa Queiroz, also married a distant cousin, only to later discover they shared a common ancestor. “In Serrinha dos Pintos, deep down, we’re all cousins. We’re related to everyone,” Larissa admitted.
Now part of a genetic screening initiative by Brazil’s Ministry of Health, couples like Larissa and her husband are tested for genes linked to serious recessive conditions. The aim isn’t to discourage cousin marriages, Santos explains, but to help families make informed choices.
Legacy Beyond the Lab
Though Santos no longer lives in Serrinha, she frequently visits and now leads a genetics education center and advocates for expanded testing in Brazil’s northeast. Her efforts have redefined how one small town understands family, illness, and science.
“It’s as if Santos is family,” Inés said, a sentiment echoed across the community.
