# NM_001110556.2(FLNA):c.72G>A (p.Arg24=)

https://sugi.bio/variant/flna-p-arg24

## Summary

**FLNA p.Arg24= (c.72G>A)** is classified **Likely benign** in FLNA (ClinVar, Multiple submitters, 2 submitters; last evaluated 2020-02-02). Very rare (popmax 0.000113%, nfe); Associated with familial thoracic aortic aneurysm and aortic dissection.

**At a glance:** Likely benign · review: Multiple submitters · rsID rs1603363947 · 2 submitters · 5 linked conditions · very rare (popmax 0.000113%, nfe)

## For patients & families {#patients}

This is a change in the FLNA gene that is classified as likely benign — not considered disease-causing, submitted by 2 submitters, and is linked to familial thoracic aortic aneurysm and aortic dissection.

*Reference information, not medical advice, and not a prediction for any individual. A genetic counselor or clinician can interpret what it means for you and your family.*

|  |  |
| --- | --- |
| Typical inheritance (of this condition) | Autosomal dominant |
| Age of onset (of this condition) | Adolescent, Adult, Childhood |
| Clinical trials | 2 registered for this condition — see ClinicalTrials.gov |
| Diagnostic panels | FLNA is a diagnostic-grade gene on 22 Genomics England panels |

**Commonly reported features of Familial thoracic aortic aneurysm and aortic dissection** (across patients with this condition; presentation varies — frequencies from Orphanet):

- Cutis marmorata — Very frequent (99-80%)
- Abnormality of connective tissue — Very frequent (99-80%)
- Cystic medial necrosis of the aorta — Very frequent (99-80%)
- Abnormality iris morphology — Frequent (79-30%)
- Hypertension — Frequent (79-30%)
- Cardiomegaly — Frequent (79-30%)
- Aortic regurgitation — Frequent (79-30%)
- Coronaryartery atherosclerosis — Frequent (79-30%)

**Support & next steps:** [Condition overview & support (NIH GARD)](https://rarediseases.info.nih.gov/diseases/0002249/index) · [Find a genetic counselor (NSGC)](https://findageneticcounselor.nsgc.org/).

## Identity {#identity}

| Field | Value |
| --- | --- |
| Gene | [FLNA](https://sugi.bio/atlas/gene/FLNA/) |
| Protein change (HGVS p.) | p.Arg24= |
| Coding change (HGVS c.) | c.72G>A |
| MANE Select transcript | [NM_001110556](https://www.ncbi.nlm.nih.gov/nuccore/NM_001110556) |
| dbSNP | [rs1603363947](https://www.ncbi.nlm.nih.gov/snp/rs1603363947/) |
| Variant type | single nucleotide variant |
| Location | chrX:154371174-154371174 (GRCh38) |
| ClinVar | [VCV745475](https://www.ncbi.nlm.nih.gov/clinvar/variation/745475/) |

**All HGVS expressions:** `LRG_1340:g.8465G>A`, `LRG_1340t1:c.72G>A`, `LRG_745:g.1747C>T`, `NC_000023.10:g.153599542C>T`, `NC_000023.11:g.154371174C>T`, `NG_008677.1:g.1747C>T`, `NG_011506.2:g.8465G>A`, `NM_001110556.2:c.72G>A`, `NM_001456.4:c.72G>A`

## Computational & population evidence {#evidence}

**Concordance:** Mixed / partial computational evidence (see below).

- **Missense predictors (AlphaMissense/REVEL/SaProt) do not apply** to this variant type — they score amino-acid substitutions only. For non-missense variants the computational signal comes from conservation (below), not from a missing predictor score.
- Conservation: phyloP -2.83, GERP -2.95 — fast-evolving / accelerated position
- CADD: **PHRED 10.45**. No single ClinGen-calibrated threshold exists and the expert panels that use CADD disagree — GUCY2D/AIPL1 require ≥ 20.0 for an untranslated-region variant, ABCA4 ≥ 28.1 for a synonymous or indel variant, the Pulmonary Hypertension panel imports Pejaver 2022's missense-calibrated numbers, and the Antibody Deficiencies panel declines CADD entirely for PIK3CD. CADD v1.7 also incorporates Zoonomia phyloP, so it partly re-expresses the conservation above. *Descriptive; no threshold applied.*
- SpliceAI: **not assessed** — no allele at this position is in our SpliceAI release, either because it lies outside the scored MANE transcript scope or because every allele is below Δ0.2. We cannot tell which, so this claims neither; absence is not evidence against a splicing effect.
- Population frequency (gnomAD v4.1): grpmax **0.000113%** (nfe) · 1/888,298 in the highest group · 1/1,082,927 alleles overall — very rare (popmax 0.000113%, nfe).

*Computational predictors are not independent (ClinGen Variant Classification guidance): AlphaMissense (Cheng et al. 2023) carries the ACMG weight for missense and conservation (phyloP/GERP/phastCons) for non-missense; REVEL (Pejaver-2022 calibrated strength bands) and SaProt (Su et al. 2023, structure-aware, ClinVar-independent protein language model, raw LLR) are shown as orthogonal agreement signals, not additive. For frequency, the gnomAD v4.1 grpmax filtering allele frequency (FAF95) is ClinGen's designated BA1/BS1 input (gnomAD v4 guidance v3.0, June 2025); BA1/BS1 thresholds are disease-specific, not a blanket 5%. Predictions, not a clinical determination.*

## Gene constraint & dosage {#gene-context}

**FLNA** population constraint: ClinGen dosage — haploinsufficiency 3, triplosensitivity 0 (0–3 scale). *Lower LOEUF and higher pLI indicate a gene that tolerates loss-of-function poorly; ClinGen dosage is the curated haploinsufficiency call.*

Curated gene–disease validity (ClinGen):

- **periventricular nodular heterotopia** — Definitive (XL)
- **familial thoracic aortic aneurysm and aortic dissection** — Limited (XL)

## Protein context {#protein}

Residue **24** lies in the 'disordered' region; the 'actin-binding' region.

AlphaFold model confidence (whole protein): pLDDT 77.37, 11% of residues very-high.

**26 experimental structure(s)** (PDB): [2AAV](https://www.rcsb.org/structure/2AAV), [2BP3](https://www.rcsb.org/structure/2BP3), [2BRQ](https://www.rcsb.org/structure/2BRQ), [2J3S](https://www.rcsb.org/structure/2J3S), [2JF1](https://www.rcsb.org/structure/2JF1), [2K3T](https://www.rcsb.org/structure/2K3T) — incl. mutant structure 3HOC.

## What this gene does {#gene-function}

*Describes the biological roles of FLNA (the gene this variant disrupts) — not effects measured for this specific variant. A damaging variant is expected to affect these functions and pathways; the degree depends on the variant.*

**How this variant is thought to act:** FLNA's established molecular role includes G protein-coupled receptor binding. p.Arg24= falls in the disordered region.


### Pathways affected {#pathways}

FLNA participates in **5 Reactome pathways** (⚕ = disease pathway):

| Pathway (Reactome) | Evidence |
| --- | --- |
| [Cell-extracellular matrix interactions](https://reactome.org/content/detail/R-HSA-446353) | curated |
| [GP1b-IX-V activation signalling](https://reactome.org/content/detail/R-HSA-430116) | curated |
| [OAS antiviral response](https://reactome.org/content/detail/R-HSA-8983711) | curated |
| [Platelet degranulation ](https://reactome.org/content/detail/R-HSA-114608) | curated |
| [RHO GTPases activate PAKs](https://reactome.org/content/detail/R-HSA-5627123) | curated |

### Molecular function & processes (GO — experimentally supported) {#go}

**Molecular function:** G protein-coupled receptor binding, RNA binding, potassium channel regulator activity, kinase binding, small GTPase binding, Fc-gamma receptor I complex binding.

**Biological process:** adenylate cyclase-inhibiting dopamine receptor signaling pathway, negative regulation of transcription by RNA polymerase I, actin cytoskeleton organization, regulation of cell migration, protein localization to cell surface, negative regulation of protein catabolic process.

## Clinical significance {#significance}

**Likely benign** — review status Multiple submitters *(criteria provided, multiple submitters, no conflicts)*, last evaluated 2020-02-02.

**Submitter consensus:** unanimous (2/2 Likely benign).

**Submission history:** 2 submissions (2018–2020); classifications have been stable.

### Submitter classifications {#submitters}

| Submitter | Classification | Review | Method | Date |
| --- | --- | --- | --- | --- |
| Ambry Genetics | Likely benign | criteria provided, single submitter | clinical testing | 2020-02-02 |
| Labcorp Genetics (formerly Invitae), Labcorp | Likely benign | criteria provided, single submitter | clinical testing | 2018-03-09 |

## Associated conditions {#conditions}

[familial thoracic aortic aneurysm and aortic dissection](https://sugi.bio/atlas/disease/familial-thoracic-aortic-aneurysm-and-aortic-dissection/), [heterotopia, periventricular, X-linked dominant](https://sugi.bio/atlas/disease/heterotopia-periventricular-x-linked-dominant/), [otopalatodigital syndrome type 2](https://sugi.bio/atlas/disease/otopalatodigital-syndrome-type-2/), [Melnick-Needles syndrome](https://sugi.bio/atlas/disease/melnick-needles-syndrome/), [frontometaphyseal dysplasia](https://sugi.bio/atlas/disease/frontometaphyseal-dysplasia/).

**Reported phenotype names (ClinVar):** Familial thoracic aortic aneurysm and aortic dissection, Frontometaphyseal dysplasia, Heterotopia, periventricular, X-linked dominant, Melnick-Needles syndrome, Oto-palato-digital syndrome, type II, Thoracic aortic aneurysms and dissections, PERIVENTRICULAR NODULAR HETEROTOPIA 4, HETEROTOPIA, PERIVENTRICULAR, 1, PERIVENTRICULAR NODULAR HETEROTOPIA 1, X-linked periventricular heterotopia.

## Similar variants {#similar}

Related FLNA variant pages (same residue, condition, or type): [FLNA p.Arg24Gly](/variant/flna-p-arg24gly), [FLNA p.Arg24Trp](/variant/flna-p-arg24trp), [FLNA p.Arg24Leu](/variant/flna-p-arg24leu), [FLNA p.Arg24Pro](/variant/flna-p-arg24pro), [FLNA c.1066-1G>A](/variant/flna-c-1066-minus-1g-a), [FLNA c.2022+1G>A](/variant/flna-c-2022-plus-1g-a), [FLNA c.4598+1G>A](/variant/flna-c-4598-plus-1g-a), [FLNA c.5417-2A>G](/variant/flna-c-5417-minus-2a-g).

### Data sources & attribution {#sources}

ClinVar (NCBI — public domain, built 2026-10-14); gnomAD v4.1 (Broad Institute, built 2026-10-06); AlphaMissense (Cheng et al. 2023, © Google DeepMind — CC BY 4.0, built 2026-01-27); REVEL (Ioannidis et al. 2016 — ODbL, built 2026-07-13); SaProt (Su et al. 2023 — MIT, built 2026-07-14); SpliceAI (Illumina — free for non-commercial use, built 2026-10-13); CADD (Rentzsch et al. 2019, University of Washington — free for non-commercial use, built 2026-10-10); Conservation (phyloP/phastCons/GERP) (UCSC hg38 470-way mammal (Hiller Lab) + Ensembl Compara, built 2026-07-12); gnomAD Non-coding Constraint (Gnocchi) (Chen et al. 2024, Broad Institute — CC0, built 2026-10-11); gnomAD Regional Missense Constraint (Broad Institute — CC0, built 2026-10-13); Pangolin (Zeng & Li 2022 — CC BY 4.0, built 2026-10-11); Repeat regions (UCSC — RepeatMasker, TRF, segmental duplications, built 2026-10-11); ClinGen (ClinGen, built 2026-09-22); UniProt (CC BY 4.0); Reactome / GO (CC BY 4.0, built 2026-09-23); MaveDB (per-record license, built 2026-10-11); CIViC (CC0, built 2026-09-22); Orphanet (Orphanet, built 2026-06-12)

*Primary record: NCBI ClinVar (variation 745475). Classifications reflect these databases as of the page's build date and may change. Free reference use — not medical advice; consult the primary submitters and a clinician.*