Kleefstra Syndrome
New Kleefstra syndrome research, summarized each month in plain language.
2026 so far: So far in 2026 (January to September), an international care guideline organized KLEFS1 diagnosis and follow-up, and an observational cohort reported adaptive-functioning improvements with olanzapine in some people. Read the 2026 review
We also cover clinical trials.
Yearly update
2026 so far
- Olanzapine and daily skills. A real-world medication signal was paired with mechanism work.
- Guideline-based care plan. Care became more structured, while evidence gaps were highlighted.
- Development, sleep, and heart rhythm. Reports added concrete reference ranges and flagged under-detected issues.
- Sharper genetic answers. More causes and clearer variant interpretation reduced some uncertainty.
- Faster lab models. Infrastructure advanced toward quicker testing of tailored approaches.
New
September 2026
- EHMT1 variant groups. More EHMT1 missense variants were grouped as likely tolerated or damaging.
- Protein effects in lab. Some variants lowered protein stability or weakened target binding in lab tests.
- Patient neuron models. Patient samples were turned into stem cells and neurons more quickly.
- Oligonucleotide designs. Oligonucleotide treatment designs were made quickly, without testing in people.
July 2026
- EHMT2 gene link. Reports more clearly linked EHMT2 changes to Kleefstra-like features.
- DNA methylation match. Some EHMT2 cases shared a DNA methylation pattern with Kleefstra type 1.
- Variant type differences. Both de novo and inherited EHMT2 changes were described.
June 2026
- Daily skills signal. Reports linked olanzapine to better daily skills in some people.
- S100B and overactivity. Lab models linked S100B to overactive brain signaling.
- Methylation test matches. A methylation DNA test matched some people to known syndromes.
May 2026
- Tracking identity and relationships. Parents want future treatment studies to track changes in identity and relationships, not only medical or skill outcomes.
- Family roles and connections. Some parents worry that changes in abilities could shift family roles and relationships over time.
- Genetic diagnosis in Rwanda. One case report confirmed a new EHMT1-related diagnosis of Kleefstra syndrome in Rwanda.
March 2026
- 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.
February 2026
- Milestone timing ranges. In a larger group of people with Kleefstra syndrome, rolling, sitting, walking, and first words were reported at later ages, giving reference ranges without setting a single expected timeline.
- QT changes with exercise. In one child with Kleefstra syndrome, QT prolongation appeared during exercise testing even though the resting ECG was normal, suggesting some rhythm changes may only show up under stress.
- EHMT1 and rhythm (hypothesis). Researchers discussed a possible link between EHMT1 and heart rhythm control, but this remains a hypothesis rather than a confirmed explanation.
January 2026
- Care plan. A new guideline pulled everyday care into one plan.
- Follow-up schedule. The guideline outlines ongoing checkups across common health concerns.
- Genetic testing steps. More than one genetic test may be needed after unclear results.
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