Dr. Tjitske Kleefstra

Dr. Tjitske Kleefstra

If you have received a diagnosis of KMT2C and would like to make contact with other families please visit the KMT2C Families and Support Facebook group.

There have been a number of discussions in the KS community recently regarding Kleefstra syndrome and KMT2C (recently named KS2). We wrote to Dr Kleefstra and asked her to provide us with a statement to help clear up any confusion.

Is Kleefstra syndrome and KMT2C the same condition?

“It is really confusing. I also receive many mails from parents/professionals directly with this topic.

I already sent the OMIM database last year a statement that these are two different conditions and that they should remove kleefstra from the designation of the disorder caused by the gene KMT2C, but they have not yet updated their information.

The EHMT1 is in fact KMT1D, and both KMT2C and KMT1D are encoding a protein with very similar activities. Mutations in both genes are causing ID/autism.

In our research we studied a cohort with overlapping features to KS, ‘Kleefstra syndrome like’ but who had no EHMT1/KMT1D mutations and in several we found mutations in other genes, among them KMT2C. We found based on drosophila (fruitfly) modeling that there is a biological interaction between KMT2C and KMT1D/EHMT1, suggesting that there is some clinical and functional overlap.

Now more patients are being diagnosed with KMT2C mutations and I am currently collaborating with Dr. Sid Banka to describe more exactly what is the KMT2C related disorder.”

Tjitske Kleefstra, December 2018.

Page updated: 18-02-2019