How is achromatopsia 4 inherited?

achromatopsia 4 follows an autosomal recessive inheritance pattern. This means a child must inherit a copy of the altered gene from both parents to develop the condition. Parents who each carry one copy typically do not show symptoms.

How is achromatopsia 4 diagnosed?

Information about diagnosis is currently limited for this condition.

Are there treatments for achromatopsia 4?

Information about treatment is currently limited for this condition.

What complications might arise from achromatopsia 4?

Currently, there is limited information about specific complications related to achromatopsia 4. However, individuals may face challenges with activities that require color discrimination, which can affect daily tasks and safety. It's important to stay informed as more research may provide additional insights into potential complications.

How does achromatopsia 4 affect daily life?

Living with achromatopsia 4 can make it difficult to distinguish between colors, which may impact activities like driving, choosing clothing, or even reading color-coded materials. People with this condition may need to develop strategies to adapt to these challenges, such as using labels or relying on brightness and patterns instead of color.

What is the prognosis for someone with achromatopsia 4?

Information about the long-term prognosis for individuals with achromatopsia 4 is currently limited. Since this condition primarily affects color vision, many people may lead normal lives but might need support in specific areas. Ongoing research may eventually provide a clearer understanding of the condition's progression and impact.

Are there any specialists I should see for achromatopsia 4?

While specific recommendations for specialists are not detailed, it is generally helpful for individuals with achromatopsia 4 to consult with an eye care professional who understands genetic vision disorders. They can provide guidance on managing symptoms and adapting to the challenges of living with this condition.

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achromatopsia 4 (ACHM4) - Clinical Profile, Genes & Research | Kisho | Kisho

Rare Disease

achromatopsia 4

MONDO:0013465

Also known as:ACHM4GNAT2 achromatopsiaachromatopsia caused by mutation in GNAT2

Overview

Any achromatopsia in which the cause of the disease is a mutation in the GNAT2 gene.

GeneticsAutosomal recessive · GNAT2 (chr 1)

Clinical Presentation

Built from Human Phenotype Ontology (HPO) phenotype annotations and GeneReviews clinical descriptions. Features represent findings documented across known cases — not an exhaustive list of possible symptoms.

Features include: Nystagmus, Photophobia, Visual impairment, and Achromatopsia.

Organ System	Phenotype Count	Example Features
Eyes	2	Nystagmus, Visual impairment

Genetic Landscape

Assembled from HGNC gene records, ClinGen gene-disease validity evidence, and ClinVar pathogenic variant data. Validity classifications reflect the strength of published evidence linking each gene to this disease.

GNAT2 encodes G protein subunit alpha transducin 2 (354 aa). Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems.

Achromatopsia 4 is associated with mutations in the GNAT2 gene on chromosome 1.

The GNAT2 protein participates in Opsins act as GEFs for G alpha-t pathway.

GNAT2 is classified as a druggable target with score 0.0.

Diagnosis

Drawn from GeneReviews diagnostic guidelines, newborn screening panel status (RUSP), and ClinGen gene-disease validity classifications. Reflects current clinical evidence and consensus where available.

GeneReviews

Diagnostic Criteria

Suggestive Findings

Achromatopsia should be suspected in individuals with the following typical clinical findings, additional testing, and family history.

Clinical findings

Pendular nystagmus
Increased sensitivity to light (photophobia)
Eccentric fixation

Treatment

Compiled from FDA-approved drug records, orphan drug designations, and FDA Adverse Event Reporting System (FAERS) safety data. GeneReviews management guidance is included where available.

No approved treatments are currently available for achromatopsia 4. The disease remains an area of unmet medical need.

GeneReviews

Management Guidelines

Evaluations Following Initial Diagnosis

To establish the extent of disease and needs in an individual diagnosed with achromatopsia, the evaluations summarized in this section (if not performed as part of the evaluation that led to the diagnosis) are recommended:

Standard clinical ophthalmologic evaluation and testing with attention to visual acuity and use of spectacles and/or contact lenses to achieve the best possible corrected visual acuity

Prognosis

Based on GeneReviews surveillance recommendations, HPO phenotype frequency and severity annotations, and published prevalence estimates from Orphanet and OMIM.

GeneReviews

Surveillance Guidelines

Ophthalmologic examination is indicated:

Every six to 12 months in children to monitor changes in refraction in order to achieve the best possible corrected visual acuity;
Every two to three years in adults.

Source: GeneReviews — "Achromatopsia"

Research Landscape

Sourced from ClinicalTrials.gov and PubMed. Publication types are classified using NLM-curated article metadata; research type breakdowns reflect the nature of published work for this disease.

No clinical trials have been registered for achromatopsia 4.

59 publications have been identified in PubMed for achromatopsia 4. Research spans Epidemiology / Natural History (24%), Basic Science / Preclinical (19%), and Review / Meta-Analysis (13%).

Research Type	Count	% of Total
Disease patterns and progression	13	24%

Data assembled from 6 of 12 sources · Last updated Sep 19, 2026, 6:42 AM UTC

MONDOHPOClinicalTrials.govFDAPubMedHGNCClinVarClinGenGeneReviewsOrphanetOMIMRUSP

Medical References

External Resources

OMIM

Online Mendelian Inheritance in Man

OMIM:613856

GARD

Genetic and Rare Diseases Info Center

GARD:15723

Questions for Your Care Team

→Should my partner and I meet with a genetic counselor to discuss carrier status and family planning?
→Are there specialists or centers of excellence for this condition in my area?
→Is there a patient registry I should consider joining?

FAQ

Frequently Asked Questions

Common questions about achromatopsia 4

Achromatopsia 4 is a type of achromatopsia caused by a mutation in the GNAT2 gene. This condition is defined by the absence or impairment of color vision. It is one of several forms of achromatopsia, and in this type the change in the GNAT2 gene is the key factor leading to the condition. People with this condition may experience difficulties with color discrimination. The description is based on the known definition and recognized involvement of the GNAT2 gene. More detailed information may be available as further research is conducted.

Information about symptoms is currently limited for this condition.

Achromatopsia 4 is caused by a mutation in the GNAT2 gene. This genetic change is the direct cause of the condition, leading to an abnormal development or function in the cells responsible for color vision. Associated genes include GNAT2.

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GeneReviews

Differential Diagnosis

Achromatopsia is readily recognized by its characteristic features . Conditions to consider in the differential diagnosis are congenital nystagmus (as nystagmus is usually one of the first manifestations) and cerebral achromatopsia or dyschromatopsia, which is associated with severe or total color vision deficits and can arise adventitiously after brain fever, cortical trauma, or cerebral infarction, especially involving lesions to the ventral occipital cortex . Inherited retinal dystrophies that may be confused with achromatopsia are summarized in . Table 3. Inherited Retinal Dystrophies to Consider in the Differential Diagnosis of Achromatopsia

Disorder	Gene(s)	MOI	Overlapping Clinical Features	Distinguishing Clinical Features	Comments
Blue-cone monochromatism1 (OMIM 303700)	OPN1LW; OPN1MW2	XL3	Severely visual acuity; Eccentric fixation; ± Infantile nystagmus; No obvious fundus abnormalities; Poor or no color discrimination4; Peak of photopic luminosity function is near 440 nm (the peak sensitivity of the S cones), not 507 nm (the peak sensitivity of the rods).	A special 4-color plate test or a 2-color filter test can clinically distinguish blue-cone monochromats from achromats (rod monochromats).; Cone ERG responses can be elicited by presenting blue flashes on a yellow background (because the S cones are functioning in addition to the rods).	—
Hereditary red-green color vision defects (OMIM 303800, 303900)	OPN1LW, OPN1MW	XL	Color vision defects5	In hereditary red-green color vision defects:; Most individuals w/protanomalous deuteranomalous color vision defects (i.e., anomalous trichromats) have no major problems in naming colors.	Clinical chart tests widely used to detect red-green color vision defects include Ishihara plates the American Optical HRR pseudoisochromatic plates.
OPN1SW	AD	Color confusion	Other non-congenital yellow-blue deficits (similar in some ways to tritan defects) may result from aging or disorders of choroid, pigment epithelium, retina, or optic nerve (e.g., optic atrophy type 1; OMIM 165500); they are usually progressive have other related signs; e.g.	—	—

Source: GeneReviews — "Achromatopsia"

Kisho

achromatopsia 4

Overview

Clinical Presentation

Genetic Landscape

Diagnosis

Diagnostic Criteria

Suggestive Findings

Treatment

Management Guidelines

Evaluations Following Initial Diagnosis

Prognosis

Surveillance Guidelines

Research Landscape

Medical References

External Resources

OMIM

GARD

Questions for Your Care Team

Questions for Your Care Team

FAQ

Frequently Asked Questions

Clinical Guidance

Explore clinical features

Differential Diagnosis

Treatment of Manifestations

Surveillance

Agents/Circumstances to Avoid

Clinical Guidance

Therapies Under Investigation

Clinical Trials

Recent Publications

Latest News & Developments

Progressive cone dystrophy in PDE6C-associated achromatopsia with a likely pathogenic variant and a VUS.

Gene Therapy for Rare Eye Disease to Advance to Human Trial | Managed Healthcare Executive

achromatopsia 4

Overview

Clinical Presentation

Genetic Landscape

Diagnosis

Diagnostic Criteria

Suggestive Findings

Treatment

Management Guidelines

Evaluations Following Initial Diagnosis

Prognosis

Surveillance Guidelines

Research Landscape

Medical References

External Resources

OMIM

GARD

Related Diseases

Questions for Your Care Team

Questions for Your Care Team

FAQ

Frequently Asked Questions

What is achromatopsia 4?

What are the symptoms of achromatopsia 4?

What causes achromatopsia 4?

How is achromatopsia 4 inherited?

How is achromatopsia 4 diagnosed?

Are there treatments for achromatopsia 4?

What complications might arise from achromatopsia 4?

How does achromatopsia 4 affect daily life?

What is the prognosis for someone with achromatopsia 4?

Are there any specialists I should see for achromatopsia 4?

Clinical Guidance

Explore clinical features

Differential Diagnosis

Treatment of Manifestations

Surveillance

Agents/Circumstances to Avoid

Clinical Guidance

Therapies Under Investigation

Clinical Trials

Recent Publications

Latest News & Developments

Progressive cone dystrophy in PDE6C-associated achromatopsia with a likely pathogenic variant and a VUS.

Gene Therapy for Rare Eye Disease to Advance to Human Trial | Managed Healthcare Executive