SDAD1

Chr 4

SDA1 domain containing 1

Also known as: Sda1

NCBI Gene: 55153 ENSG00000198301 UniProt: Q9NVU7

The SDAD1 protein is required for export of 60S pre-ribosomal subunits from the nucleus to the cytoplasm, functioning in ribosomal large subunit biogenesis. Mutations cause autosomal recessive intellectual disability with microcephaly, short stature, and distinctive facial features. The gene shows minimal constraint against loss-of-function variants based on population data.

ResearchSummary from RefSeq, UniProt

Predicted to be involved in ribosomal large subunit biogenesis and ribosomal large subunit export from nucleus. Predicted to act upstream of or within cellular response to leukemia inhibitory factor. Located in nucleolus. [provided by Alliance of Genome Resources, Jun 2026]

ResearchGenerating clinical summary…

Active trials

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Pubs (1 yr)

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P/LP submissions

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P/LP missense

1.04

LOEUF

Mechanism· predicted

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Tolerant — LoF & missense variants common in population

LoF Constraint?

1.04LOEUF

pLI 0.000

Z-score 1.31

OE 0.79 (0.60–1.04)

Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint?

-0.03Z-score

OE missense 1.00 (0.92–1.10)

362 obs / 360.3 exp

Tolerant

Tolerant to missense variation

Observed / Expected Ratios?

LoF OE?0.79 (0.60–1.04)

0≤0.351.4

Missense OE?1.00 (0.92–1.10)

0≤0.61.4

Synonymous OE?0.98

0≤1.21.6

LoF obs/exp: 36 / 45.5Missense obs/exp: 362 / 360.3Syn Z: 0.18

Background carrier burden — how many people carry a rare variant somewhere in SDAD1?

gnomAD v4 · ~731k individuals · PASS only

Rare means allele frequency under

Rare missense

1 in 71

851 rare PASS variants

Rare truncating (LoF)

1 in 1,000

151 rare PASS variants

Rare synonymous (reference)

1 in 270

290 rare PASS variants

Truncating variants are far rarer here than missense — that gap, in human units, is what constraint means for SDAD1. 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 94	1 in 1,300
South Asian	~43k	1 in 56	1 in 410
Remaining (unassigned)	~30k	1 in 64	1 in 570
European (Finnish)	~27k	1 in 230	1 in 2,200
Admixed American	~22k	1 in 56	1 in 1,200
African / African American	~21k	1 in 54	1 in 640
East Asian	~20k	1 in 67	1 in 840
Ashkenazi Jewish	~13k	1 in 270	none seen
Middle Eastern	~2,884	1 in 74	≈ 1 in 950

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): 20 of 22 coding exons well covered in gnomAD exomes; exons 5, 22 marginal. Genomes: all 22.? see exons ↓