HYDIN

Chr 16

HYDIN axonemal central pair apparatus protein

Also known as: CILD5, HYDIN1, PPP1R31

NCBI Gene: 54768 ENSG00000157423 UniProt: Q4G0P3

The protein is required for ciliary motility and maintains proper cilia function. Mutations cause autosomal recessive primary ciliary dyskinesia-5, characterized by accumulation of cerebrospinal fluid within the brain ventricles. The gene shows moderate constraint against loss-of-function variants (LOEUF 0.505).

GeneReviews ResearchSummary from RefSeq, OMIM, UniProt

This gene encodes a protein that may be involved in cilia motility. Mutations in this gene cause of autosomal recessive primary ciliary dyskinesia-5, a disorder characterized by the accumulation of cerebrospinal fluid within the ventricles of the brain. A duplicate copy of this gene has been found in humans on chromosome 1. [provided by RefSeq, Jan 2013]

GeneReviews ResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProtCiliary dyskinesia, primary, 5

Clinical highlights

Gene–disease validity (ClinGen)

Definitive · primary ciliary dyskinesia 5 · AR · ClinGen 2022

Interpreting a novel variant

Loss of function is the curated mechanism (Gene2Phenotype), though the gene is not strongly LoF-constrained in the population — weigh truncating variants against that tolerance.Curated gene-level mechanism — a prior for triage, not a per-variant call.

Active trials

Pubs (1 yr)

—

P/LP submissions

—

P/LP missense

0.51

LOEUF

LOF

Mechanism· G2P

📖

GeneReview available — HYDIN

Authoritative clinical overview · Recommended first read

Open GeneReview ↗

Some data sources returned errors (1)

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD

Moderate LoF intolerance

LoF Constraint?

0.51LOEUF

pLI 0.000

Z-score 7.14

OE 0.42 (0.34–0.51)

Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint?

0.81Z-score

OE missense 0.95 (0.92–0.99)

1990 obs / 2094.3 exp

Tolerant

Mild missense constraint

Observed / Expected Ratios?

LoF OE?0.42 (0.34–0.51)

0≤0.351.4

Missense OE?0.95 (0.92–0.99)

0≤0.61.4

Synonymous OE?1.04

0≤1.21.6

LoF obs/exp: 72 / 173.5Missense obs/exp: 1990 / 2094.3Syn Z: -0.97

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

gnomAD v4 · ~731k individuals · PASS only

Rare means allele frequency under

Rare missense

1 in 11

3,391 rare PASS variants

Rare truncating (LoF)

1 in 230

313 rare PASS variants

Rare synonymous (reference)

1 in 22

1,440 rare PASS variants

Truncating variants are far rarer here than missense — that gap, in human units, is what constraint means for HYDIN. 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 14	1 in 290
South Asian	~43k	1 in 11	1 in 240
Remaining (unassigned)	~30k	1 in 10	1 in 240
European (Finnish)	~27k	1 in 24	1 in 600
Admixed American	~22k	1 in 10	1 in 340
African / African American	~21k	1 in 10	1 in 220
East Asian	~20k	1 in 14	1 in 220
Ashkenazi Jewish	~13k	1 in 35	1 in 1,600
Middle Eastern	~2,884	1 in 11	≈ 1 in 1,400

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): 33 of 85 coding exons well covered in gnomAD exomes; exons 6, 8, 10, 12, 13 and 27 more poorly covered; exons 3, 4, 7, 17, 20 and 15 more marginal. Genomes: 33 of 85 (exons 6, 8, 12, 13, 18 and 47 more below).? see exons ↓