MLLT3

Chr 9

MLLT3 super elongation complex subunit

Also known as: AF9, YEATS3

NCBI Gene: 4300 ENSG00000171843 UniProt: P42568 OMIM: 159558

MLLT3 encodes a chromatin reader component of the super elongation complex that recognizes acetylated and crotonylated histones to promote RNA polymerase II transcription and maintain hematopoietic stem cell function. Mutations cause autosomal dominant neurodevelopmental disorder with developmental delay, intellectual disability, and behavioral abnormalities. This gene is highly constrained against loss-of-function mutations (pLI 0.999, LOEUF 0.131), consistent with its essential role in transcriptional regulation.

OMIM ResearchSummary from RefSeq, UniProt

Enables several functions, including chromatin binding activity; histone H3 reader activity; and histone binding activity. Involved in several processes, including hematopoietic stem cell differentiation; positive regulation of DNA-templated transcription; and regulation of stem cell division. Acts upstream of or within negative regulation of canonical Wnt signaling pathway and positive regulation of Wnt signaling pathway, planar cell polarity pathway. Located in nucleoplasm. Part of transcription elongation factor complex. [provided by Alliance of Genome Resources, Jun 2026]

OMIM ResearchGenerating clinical summary…

Clinical highlights

Interpreting a novel variant

This gene is strongly intolerant of loss-of-function variation in the population, so LoF variants warrant close attention. No curated mechanism annotation is available — see the mechanism card for the computational prediction and its caveats.Based on population constraint only.

Active trials

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

0.13

LOEUF· LoF intol.

LOF

Mechanism· predicted