Hi everyone! I just wanted to give a quick update on our Timothy Syndrome Natural History Study that I believe all of you have participated in by filling out a rather long survey. Thanks for your participation!
So that we all have a better feel for what the Timothy Syndrome Community is made of, we have tabulated the number of cases of each type since the first observations in 1992 in Germany, Africa, and the US. Based on survey responses and previously published case reports since 2004, we currently know of 48 TS1 families, 13 TS2 families, and 11 Gly402Ser families. From our survey and published reports, the Gly402Ser variant should be reclassified as part of the larger non-syndromic LQT8 group of families. Like the LQT families that many of you may have learned about from the SADS Foundation, Gly402Ser variants in the CACNA1C gene can be heritable from generation to generation, as well as occur de novo. However, it is rare that these individuals have extra-cardiac symptoms common to our TS1 and TS2 individuals. There are many more variants that account for non-syndromic LQT8, and Gly402Ser appears to be one of them. Some of the others are: Ala28Thr, Leu207Arg, Ile304Thr, Arg518Cys, Arg518His, Glu771Lys, Arg858His, and Gly2573Ala. We do intend to continue to survey families with variants other than the typical Gly406Arg variant of TS1 and TS2 to help determine if they have a more TS-like syndrome or non-syndromic LQT8.
Individuals with variants other than Gly406Arg that do present with symptoms remarkably like TS1 and TS2 include those with Ser405Arg, Cys1021Arg, Ile1166Thr, and Arg1473Gly. These appear to arise de novo and have only been observed in 1-3 individuals each.
So, we’re a small family with serious medical concerns. Documenting ALL of the symptoms that our kids experience is important for a greater understanding of this disease and for determining therapies to improve the quality of life for our TS kids and young adults.