The way in which genetic mutations cause a number of rare human diseases, such as Meckel syndrome, Joubert syndrome and several other disorders has been discovered by scientists.
Meckel syndrome causes deadly brain malformations and kidney cysts. Joubert syndrome strikes people with severe movement disorders.
The result gives doctors new possible targets for designing better diagnostics to detect and drugs to treat these diseases.
The study led by University of California, San Francisco, found similarities between the diseases at the molecular level.
"We think these diseases have a common underlying cause. They are fundamentally caused by defects in 'antenna' on cells," said UCSF developmental biologist Jeremy Reiter.
Technically known as cilia, these antennae are protrusions that dangle off cells and, like tiny receivers, allow the cells to explore and interact with their environment.
These antennae are found everywhere from the brain to the eyes to the lungs in humans.
Reiter and his colleagues looked at the DNA of twins from Bangladesh born with Joubert syndrome, and they showed how certain mutations associated with the disease work.
They found that these mutations lead to malfunctions in a protein called Tectonic1, one of several that forms a crucial collar around the base of a cilium.
Similarly, mutations in Tectonic1 prevent the collar from forming correctly, and this causes defects in the cilia within the brain and ultimately leads to Joubert syndrome, they found.
The study was published this week in the journal Nature Genetics.