Some children are born without a nose, a rare condition whose genetic basis was unknown until now. A*STAR scientists in Singapore recently solved the mystery by identifying the gene that allows the nose to form when the baby is in the mother’s womb.
When gene SMCHD1 is mutated, the nose does not form, resulting in a condition known as congenital arhinia. Since 1981, fewer than 100 cases have been reported in medical literature.
Children born without a nose experience typically need to undergo a tracheotomy (an incision in the windpipe) to allow them to breathe during breastfeeding. They will never experience the sense of smell. They may also have eye and reproductive defects, some of which may develop at a later stage in their lives.
The SMCHD1 gene has been previously linked with a completely unrelated but more common condition called facioscapulohumeral muscular dystrophy type 2, a muscle-weakening disorder that mostly affects the face, shoulders and upper arms. A better understanding of the gene may help scientists develop a therapy for this condition.
The gene discovery, published in Nature Genetics on 9 January this year, was led by researchers from A*STAR’s Institute of Medical Biology, Institute of Molecular and Cell Biology and Genome Institute of Singapore, in collaboration with a multinational team of researchers and clinicians based in France, Germany and Australia.