Microcephaly
Gene: RNU6ATAC
MedRxiv preprint Johnson et al., 2025 doi: https://doi.org/10.1101/2025.09.12.25335567
Identified 19 individuals with early-onset diabetes (diagnosed <5 years) and additional clinical features who had biallelic pathogenic variants in the novel disease gene RNU6ATAC (n=7) or in RNU4ATAC (n=12). 12/19 had additional immune features of immune dysregulation. Around 60% of patients also had microcephaly and developmental delay.
Among the 4 families with biallelic RNU6ATAC variants, the variants reported were: n.4T>C, n.6G>A, n.43G>A, n.68C>A, n.71C>T (homozygous or compound het).
RNU6ATAC has not yet been linked to any phenotypes in OMIM (accessed 5th Feb 2026).
Note gene is not protein coding.Created: 5 Feb 2026, 1:10 p.m. | Last Modified: 5 Feb 2026, 1:10 p.m.
Panel Version: 1.4241
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
neonatal diabetes; humoral immunue defect; microcephaly; developmental delay.
PMID 40975062 reports 1 individual from with biallelic RNU6ATAC variants causing childhood‑onset growth restriction, microcephaly, epilepsy, intellectual disability and ataxia. PMID 41808409 reports 3 unrelated families (3 individuals) with biallelic loss‑of‑function RNU6ATAC variants presenting with short stature, neurodevelopmental delay, epilepsy, immunodeficiency, skeletal dysplasia and other multisystem features; RNA‑seq shows marked excess of minor intron retention, confirming spliceosome dysfunction.
However, note overlap in authors between the two papers ?double-counting.
PMID 41864208 -- published version of the preprint referenced in previous reviews. 7 individuals from 4 families with early-onset diabetes (diagnosed aged <5 years) and immune dysregulatory features caused by bi-allelic variants in RNU6ATAC.
Genotype-phenotype correlation unclear at this stage but note that of the three individuals reported in 41808409, one did not have ID/neurological features but all had immunological involvement.Created: 27 Mar 2026, 2:14 p.m. | Last Modified: 27 Mar 2026, 2:14 p.m.
Panel Version: 1.421
Single patient reported.Created: 10 Oct 2025, 5:02 p.m. | Last Modified: 10 Oct 2025, 5:02 p.m.
Panel Version: 1.345
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Syndromic disease, MONDO:0002254, RNU6ATAC-related
Publications
PMID: 40975062 1 patient compound heterozygous for n.36T>G and n.28C>T. Has short stature, microcephaly, hypotonia, neurodevelopmental delay, ID, seizures, ataxia, ventriculomegaly, syndactyly, nystagmus and oculomotor apraxia. Identified in a cohort of individuals with an excess of significant intron retention outliers in minor intron containing genes which are usually removed by the minor spliceosome of which RNU6ATAC is a part (as is RNU4ATAC). Proband had no candidate variants in RNU4ATAC or RNU12. Both RNU6ATAC variants are in a highly conserved 39bp region, and affect nucleotides predicted to be important for binding to U4ATAC.
Sources: LiteratureCreated: 10 Oct 2025, 1:56 p.m.
Mode of inheritance
BIALLELIC, autosomal or pseudoautosomal
Phenotypes
Neurodevelopmental disorder (MONDO:0700092), RNU6ATAC-related
Publications
Phenotypes for gene: RNU6ATAC were changed from Neurodevelopmental disorder (MONDO:0700092), RNU6ATAC-related; neonatal diabetes to Syndromic disease, MONDO:0002254, RNU6ATAC-related
Publications for gene: RNU6ATAC were set to 40975062
Gene: rnu6atac has been classified as Green List (High Evidence).
Phenotypes for gene: RNU6ATAC were changed from Neurodevelopmental disorder (MONDO:0700092), RNU6ATAC-related to Neurodevelopmental disorder (MONDO:0700092), RNU6ATAC-related; neonatal diabetes
Tag non-coding gene tag was added to gene: RNU6ATAC.
Gene: rnu6atac has been classified as Amber List (Moderate Evidence).
Gene: rnu6atac has been classified as Red List (Low Evidence).
Gene: rnu6atac has been classified as Red List (Low Evidence).
gene: RNU6ATAC was added gene: RNU6ATAC was added to Microcephaly. Sources: Literature Mode of inheritance for gene: RNU6ATAC was set to BIALLELIC, autosomal or pseudoautosomal Publications for gene: RNU6ATAC were set to 40975062 Phenotypes for gene: RNU6ATAC were set to Neurodevelopmental disorder (MONDO:0700092), RNU6ATAC-related Review for gene: RNU6ATAC was set to AMBER