March 2026 Research Update

At a glance

New KMT2C variants

A small report described additional KMT2C gene variants in people with a Kleefstra syndrome 2 (KS2) diagnosis.

Different variant classes

The reported variants included protein-shortening changes and a missense change, both of which have been seen in KS2.

Reported symptoms

The individuals had developmental and neurologic features that are consistent with prior KS2 descriptions.

What this adds (and doesn’t)

This update mainly expands the list of KS2-linked variants and does not answer treatment or care questions because only three people were reported.

Overview

This month, the main change in Kleefstra syndrome research was on the genetics side. A small report added new information about Kleefstra syndrome 2 (KS2), which is linked to changes in the KMT2C gene.

New KMT2C variants were described in three people who previously did not have a clear genetic diagnosis. The variants included changes expected to shorten the KMT2C protein and one missense change, which is a single-letter DNA change.

The people described had a set of features that match what has already been reported for KS2. These included developmental delay and speech delay. Some also had autism spectrum disorder, cognitive impairment, seizures, and craniofacial differences.

Overall, this month mainly broadened the list of KMT2C variants that have been linked to a KS2-like pattern. It did not test treatments or compare different types of care. It also cannot show how common any specific feature is because only three people were described.

Research topics this month

Limitations

• Only three people were described, so the findings cannot estimate how common features are.
• The report expanded the variant list but did not evaluate treatments or care approaches.
• The report cannot show how well a specific KMT2C variant predicts an individual symptom pattern.

Important information

• This document summarizes recent research from PubMed-indexed publications using automated methods.
• It is intended for educational purposes and does not replace medical advice.
• Links to the original studies are provided via PubMed, where readers can explore abstracts and, when available, access full-text articles.
• Some studies may include additional details that were not accessible for this summary.
• Readers seeking more complete detail or context may find it helpful to review the original studies directly.

1. 1.Sedláčková L, Brožková DŠ, Havlovicová M, Laššuthová P. Novel Variants in KMT2C Further Support a Neurodevelopmental Disorder Distinct From Kleefstra and Kabuki Syndromes. Mol Genet Genomic Med (2026). Open in new tab