Discovering which genes cause anosmia at birth could lead to gene therapies to restore the sense of smell not only for congenital anosmics, but also for others who suffer from full or partial loss of smell. The lab of Dr. Joel Mainland has been studying genetic inheritance patterns as part of a NIH grant to identify genes that cause congenital anosmia.
As of fall 2021, they have sequenced and identified more than 20,000 genes for each member in 10 families that include at least two congenital anosmics. They have now analyzed this large data set looking for patterns of gene variants that are more likely to occur in anosmic family members, both within and across different families. This research is especially challenging because researchers have identified only two genes associated with congenital smell loss, while more than 200 genes are implicated in patients born without sight and 100 altered genes have been discovered in patients born without hearing.
The Mainland group uses whole-exome sequencing, which captures all of the genes involved in protein synthesis. More than 20,000 genes are analyzed for each individual in the study. The Mainland lab has generated a list of candidate anosmia genes, and as they sequence more samples, this list will be refined to prioritize gene variants found in multiple unrelated affected individuals.
Our lack of understanding of congenital anosmia prevents many anosmics from knowing if their condition is acquired or genetic, temporary or permanent, and provides them little hope for diagnosis and treatment. The work of the Mainland lab promises to provide critical knowledge about this condition.