How these twins’ rare growth disorder could provide the key to preventing cancer

Twin sisters María Luísa and María del Cisne Romero, from the town of Piñas in southern Ecuador, both have Laron syndrome, a rare genetic condition that stops the body growing taller than about 1.2m. Researchers studying the community believe the disorder may hold clues to preventing cancer, since people with the condition appear to have lower rates of cancer and diabetes than the general population, and scientists hope to replicate this protective effect through drugs or diet for people without the syndrome.

Laron syndrome, also called growth hormone insensitivity, prevents the body from using the growth hormone it produces, and was identified 60 years ago by paediatrician Zvi Laron. Around 840 people worldwide are known to have the condition, most of them in Ecuador's El Oro and Loja provinces, with Prof Laron tracing its spread from Indonesia via Sephardic Jewish migration routes to isolated communities in the Americas. Endocrinologist Dr Jaime Guevara, who has studied the condition for 40 years, is leading research into the sisters and others with the syndrome, while Prof Laron is due to publish a new paper in July documenting all known cases recorded between 1966 and 2025.