Missing molecule prevents puberty

A molecule important in blood vessel formation and brain wiring is also essential for the onset of puberty, finds new research led by UCL and the University of Milan. The researchers found a genetic fault that prevented this molecule, called SEMA3E, from being working correctly in two brothers with Kallman Syndrome, an inherited condition that prevents people from undergoing puberty or being able to smell. They then studied mice without SEMA3E to see how its loss affected their development. SEMA3E was found to protect the nerve cells that regulate sexual reproduction. These nerve cells grow in the nose of developing foetuses and then migrate to the brain where they produce gonadotropin releasing hormone (GnRH), which is needed to stimulate puberty. The research showed that these GnRH-producing nerve cells could not survive the migration without SEMA3E to protect them. The new study, published in the Journal of Clinical Investigation, pinpointed genes responsible for Kallmann Syndrome in the two brothers and then verified the effect in tissue culture and mouse models.