RAMAC

Chr 15

RNA guanine-7 methyltransferase activating subunit

Also known as: C15orf18, FAM103A1, HsT19360, RAM, RAMMET

NCBI Gene: 83640 ENSG00000169612 UniProt: Q9BTL3 OMIM: 614547

RAMAC encodes a regulatory subunit of the mRNA-capping methyltransferase complex that methylates the N7 position of guanosine in the 5'-cap structure of mRNAs and promotes recruitment of the methyl donor S-adenosyl-L-methionine. Mutations cause autosomal recessive intellectual disability with macrocephaly, seizures, and spasticity. The gene shows tolerance to loss-of-function variants with normal constraint metrics.

OMIM ResearchSummary from RefSeq, UniProt

Enables RNA binding activity and enzyme activator activity. Involved in 7-methylguanosine mRNA capping. Located in nucleoplasm. Part of mRNA cap methyltransferase RNMT:RAMAC complex and mRNA capping enzyme complex. [provided by Alliance of Genome Resources, Jun 2026]

OMIM ResearchGenerating clinical summary…

Active trials

Pubs (1 yr)

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P/LP submissions

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P/LP missense

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LOEUF

Mechanism· predicted

Some data sources returned errors (1)

gnomad: Error: gnomAD API error: 400

Population Genetics & Constraint

gnomAD

Constraint data not available from gnomAD.

Background carrier burden — how many people carry a rare variant somewhere in RAMAC?

gnomAD v4 · ~731k individuals · PASS only

Rare means allele frequency under

Rare missense

1 in 370

122 rare PASS variants

Rare truncating (LoF)

1 in 3,300

16 rare PASS variants

Rare synonymous (reference)

1 in 2,100

30 rare PASS variants

Truncating variants are far rarer here than missense — that gap, in human units, is what constraint means for RAMAC. A background rate for each class, not the frequency of any particular variant; thin-coverage exons undercount.

By genetic ancestry · 9 gnomAD groups · rare = under 0.1% in that group

Group	People	Missense	Truncating
European (non-Finnish)	~556k	1 in 430	1 in 7,200
South Asian	~43k	1 in 240	≈ 1 in 21,000
Remaining (unassigned)	~30k	1 in 360	1 in 4,300
European (Finnish)	~27k	1 in 1,000	none seen
Admixed American	~22k	1 in 350	≈ 1 in 6,600
African / African American	~21k	1 in 200	≈ 1 in 6,400
East Asian	~20k	1 in 960	≈ 1 in 6,400
Ashkenazi Jewish	~13k	1 in 1,700	none seen
Middle Eastern	~2,881	1 in 400	none seen

Each group is summed over the variants that are rare in that group. Grey ≈ figures rest on fewer than five expected carriers — too few to distinguish groups. Differences mostly reflect how many people were sampled and how much variation each ancestry carries, not disease risk.

Exome coverage (gnomAD): 1 of 2 coding exons well covered in gnomAD exomes; exon 4 marginal. Genomes: 1 of 2 (exon 4 below).? see exons ↓