Mitochondrial myopathy-cerebellar ataxia-pigmentary retinopathy syndrome

What it is

From: Orphanet

A rare mitochondrial myopathy characterized by motor developmental delay (in infancy), growth impairment and mostly proximal muscle weakness caused by a muscular dystrophy. Muscle biopsy presents myopathic abnormalities and decreased mtDNA content. Electromyography (EMG) shows a myopathic process and serum creatine kinase is increased. The disease is also characterized by early onset non-progressive cerebellar atrophy (particularly cerebellar vermis and hemispheres), corticospinal tract dysfunction, and global or partial cerebral atrophy on brain MRI. Additionally, some patients presented with cognitive deficiencies, skeletal abnormalities, tremors, and retinopathy.

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.

Abnormality of globe size · Frequent (79-30%)

An abnormality in the size of the ocular globe (eyeball).

Anxiety · Frequent (79-30%)

Intense feelings of nervousness, tension, or panic often arise in response to interpersonal stresses. There is worry about the negative effects of past unpleasant experiences and future negative possibilities. Individuals may feel fearful, apprehensive, or threatened by uncertainty, and they may also have fears of falling apart or losing control.

Cerebellar hypoplasia · Frequent (79-30%)

Cerebellar hypoplasia is a descriptive term implying a cerebellum with a reduced volume, but a normal shape and is stable over time.

Delayed skeletal maturation · Frequent (79-30%)

A decreased rate of skeletal maturation. Delayed skeletal maturation can be diagnosed on the basis of an estimation of the bone age from radiographs of specific bones in the human body.

Delayed speech and language development · Frequent (79-30%)

A degree of language development that is significantly below the norm for a child of a specified age.

Depression · Frequent (79-30%)

Frequently experiencing feelings of being down, miserable, and/or hopeless; struggling to recover from these moods; having a pessimistic outlook on the future; feeling a pervasive sense of shame; having a low self-worth; experiencing thoughts of suicide and engaging in suicidal behavior.

Dysdiadochokinesis · Frequent (79-30%)

A type of ataxia characterized by the impairment of the ability to perform rapidly alternating movements, such as pronating and supinating his or her hand on the dorsum of the other hand as rapidly as possible.

Dysmetria · Frequent (79-30%)

A type of ataxia characterized by the inability to carry out movements with the correct range and motion across the plane of more than one joint related to incorrect estimation of the distances required for targeted movements.

EMG: myopathic abnormalities · Frequent (79-30%)

The presence of abnormal electromyographic patterns indicative of myopathy, such as small-short polyphasic motor unit potentials.

Gait disturbance · Frequent (79-30%)

The term gait disturbance can refer to any disruption of the ability to walk.

Generalized hypotonia · Frequent (79-30%)

Generalized muscular hypotonia (abnormally low muscle tone).

Generalized joint hypermobility · Frequent (79-30%)

Joint hypermobility (ability of a joint to move beyond its normal range of motion) affecting many or all joints of the body. In individuals with Joint hypermobility at multiple sites (usually five or more), the term generalized joint hypermobility is preferred.

Gowers sign · Frequent (79-30%)

A phenomenon whereby patients are not able to stand up without the use of the hands owing to weakness of the proximal muscles of the lower limbs.

Growth delay · Frequent (79-30%)

A deficiency or slowing down of growth pre- and postnatally.

Other findings in the same source

From: Orphanet

Additional reported features include Hearing impairment (Frequent (79-30%)); High palate (Frequent (79-30%)); Hyperintensity of cerebral white matter on MRI (Frequent (79-30%)); Hyperthyroidism (Frequent (79-30%)); Hyporeflexia (Frequent (79-30%)); Hypotelorism (Frequent (79-30%)); Increased circulating prolactin concentration (Frequent (79-30%)); Increased intramyocellular lipid droplets (Frequent (79-30%)); Increased muscle glycogen content (Frequent (79-30%)); Increased variability in muscle fiber diameter (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

When it may begin

From: Orphanet

Adult; Infancy

Inheritance in the source

From: Orphanet

Autosomal dominant

Frequency and the population described

From: Orphanet

Reported case(s): 9.0; Worldwide. This is a published case count, not prevalence. Point prevalence: <1 / 1 000 000; Worldwide; Class only.

Understanding the inheritance label

From: MedlinePlus Genetics

An autosomal dominant pattern means that one altered copy of a relevant gene can be sufficient for the condition. Some affected people inherit the change; others have a new change without an affected parent. The precise finding, family history and condition determine what this means for relatives.

Which doctor should you see?

The suggested department for discussing Mitochondrial myopathy-cerebellar ataxia-pigmentary retinopathy syndrome is Clinical Genetics, with a clinical geneticist as the relevant type of clinician. Paediatrician (children) or physician (adults), with clinical geneticist referral.

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

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.

• Does the exact genetic or chromosome finding explain the observed features?
• Would a genetic counsellor help the family understand the result?
• Which organ-specific assessments are appropriate for this particular diagnosis?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Mitochondrial myopathy-cerebellar ataxia-pigmentary retinopathy syndrome. 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.