TBS and ZLS are known as ‘autosomal dominant’ conditions. Our genes come in pairs, and for an autosomal dominant condition to arise, an individual only needs a mistake in one copy of that gene pair. The gene involved in TBS and ZLS is called KCNH1, which produces a protein that helps cells ‘talk’ to each other. People with TBS or ZLS have a KCNH1 error that causes an overactive protein.
Neither condition is inherited. Instead, the gene error arises as a random mistake. People with TBS or ZLS don’t tend to have children of their own, but if they do, the chance in their offspring of having a similar condition is 50%
KCNH1