Bothnia retinal dystrophy

What it is

From: Orphanet

Bothnia retinal dystrophy is a rare form of retinal dystrophy, seen mostly in Northern Sweden, presenting in early childhood with night blindness and progressive maculopathy with a decrease in visual acuity, eventually leading to blindness by adulthood. Retinal degeneration, without obvious bone spicule formation, accompanied by affected visual fields and the typical presence of retinitis punctata albescens in the posterior pole are also noted.

Reported clinical features and what the terms mean

The following findings are associated with this condition in Orphanet. They are not a checklist for diagnosing yourself, and they do not all occur in every affected person. Some are examination, imaging or laboratory findings that cannot be recognised at home.

The frequency labels describe how often a finding was reported among people with the condition in the source. They do not give the chance that a person with that symptom has the condition. Definitions below reproduce HPO terminology; they explain the term, not the likely severity in an individual.

Abnormal dark-adapted electroretinogram · Very frequent (99-80%)

An electroretinographic anomaly detected by dark-adapted full-field ERG. The dark adapted ERG targets rod-pathway function.

Color vision defect · Very frequent (99-80%)

An anomaly in the ability to discriminate between or recognize colors.

Progressive visual loss · Very frequent (99-80%)

A reduction of previously attained ability to see.

Increased OCT-measured foveal thickness · Very frequent (99-80%)

Undetectable dark-adapted electroretinogram · Very frequent (99-80%)

Visual field defect · Very frequent (99-80%)

Abnormal foveal morphology · Frequent (79-30%)

An abnormality of the fovea centralis, the central area of the macula that mediates central, high resolution vision and contains the largest concentration of cone cells in the retina.

Abnormality of refraction · Frequent (79-30%)

An abnormality in the process of focusing of light by the eye in order to produce a sharp image on the retina.

Macular degeneration · Frequent (79-30%)

A nonspecific term denoting degeneration of the retinal pigment epithelium and/or retinal photoreceptor cells of the macula lutea.

Pigmentary retinopathy · Frequent (79-30%)

An abnormality of the retina characterized by pigment deposition. It is typically associated with migration and proliferation of macrophages or retinal pigment epithelial cells into the retina; melanin from these cells causes the pigmentary changes. Pigmentary retinopathy is a common final pathway of many retinal conditions and is often associated with visual loss.

Retinal degeneration · Frequent (79-30%)

A nonspecific term denoting progressive loss of the retinal pigment epithelium (RPE) and/or neurosensory retinal cells.

Retinal pigment epithelial mottling · Frequent (79-30%)

Mottling (spots or blotches of different shades) of the retinal pigment epithelium, i.e., localized or generalized fundus pigment granularity associated with processes at the level of the retinal pigment epithelium.

Retinitis · Frequent (79-30%)

Inflammation of the retina of the eye.

Abnormal choroid morphology · Occasional (29-5%)

Any structural abnormality of the choroid (the posterior part of the uvea, the middle tunic of the eye, consisting mainly of blood vessels).

Other findings in the same source

From: Orphanet

Additional reported features include Central scotoma (Occasional (29-5%)); Electronegative electroretinogram (Occasional (29-5%)); Nyctalopia (Occasional (29-5%)); Retinal pigment epithelial atrophy (Occasional (29-5%)); Ring scotoma (Occasional (29-5%)); Rod-cone dystrophy (Occasional (29-5%)); Large central visual field defect (Occasional (29-5%)); Paracentral scotoma (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Childhood

Inheritance in the source

From: Orphanet

Autosomal recessive

Frequency and the population described

From: Orphanet

Point prevalence: Unknown; Worldwide; Class only.

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal recessive pattern usually involves disease-causing changes in both copies of a gene. Parents may each carry one altered copy without having the condition themselves. A genetic counsellor can explain carrier testing and reproductive implications using the actual laboratory findings, rather than the condition name alone.

Which doctor should you see?

The suggested department for discussing Bothnia retinal dystrophy is Ophthalmology, with a ophthalmologist as the relevant type of clinician. Ophthalmologist; paediatric services for children as appropriate.

Additional services that may be relevant, depending on the findings, include: Clinical Genetics.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Which part of the eye or visual pathway is affected?
• What change in vision requires immediate contact with the eye service?
• What are the aims and alternatives of any proposed eye treatment?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Bothnia retinal dystrophy. That gap does not mean that treatment is unavailable. A clinician needs to establish the diagnosis and review current guidance before recommending medicines, procedures, rehabilitation or other support.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

The collected references do not establish a complete prevention or long-term outlook section for this entry. Missing information should not be interpreted as proof that prevention is impossible or that a particular outcome is inevitable. Ask what is known for the exact subtype, stage and personal circumstances, and which uncertainties remain.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.