First, there are two main forms of Long QT:
It's self-explanatory, but the inherited form is genetic related and the acquired form is caused by other reasons, in particular medications that prolong the QT interval.
There are two forms of inherited long QT:
1. Romano Ward Syndrome
2. Jervell and Lange-Nielsen
The main difference is that Romano Ward is the genetic version not associated with deafness, while Jervell and Lange-Neilsen is associated with profound hearing loss/deafness from birth. JLN is still genetic and this is common if you happen to inherit genetic variants from both parents.
One Step Further:
As of this writing, there are, I believe, 15 genetic types of Long QT. It is known that more genetic variants have yet to be discovered. I won't get into all the specifics of the gene variants on here.
Some general information:
- The most common gene variants are Long QT 1, 2, and 3.
- Since they are the most common, the most research has been done on these three genes and more is known about these three genes than the other 12.
- The others are more rare and some of the latter ones have only recently been discovered.
- It is known that Long QT 5 is somewhat similar to type 1.
- Long QT 8 is also known as Timothy Syndrome.
- Timothy Syndrome is a type of long qt that includes other symptoms such as syndactyly (webbed fingers and/or toes) and developmental delays.