Marinesco-Sjögren syndrome

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Marinesco-Sjögren syndrome is a condition that has a variety of signs and symptoms affecting many tissues. People with Marinesco-Sjögren syndrome have clouding of the lens of the eyes (cataracts) that usually develops soon after birth or in early childhood. Affected individuals also have muscle weakness (myopathy) and difficulty coordinating movements (ataxia), which may impair their ability to walk. People with Marinesco-Sjögren syndrome may experience further decline in muscle function later in life.

Most people with Marinesco-Sjögren syndrome have mild to moderate intellectual disability. They also have skeletal abnormalities including short stature and a spine that curves to the side (scoliosis). Other features of Marinesco-Sjögren syndrome include eyes that do not look in the same direction (strabismus), involuntary eye movements (nystagmus), and impaired speech (dysarthria).

Affected individuals may have hypergonadotropic hypogonadism, which affects the production of hormones that direct sexual development. As a result, puberty is either delayed or absent.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Mutations in the SIL1 gene cause Marinesco-Sjögren syndrome. The SIL1 gene provides instructions for producing a protein located in a cell structure called the endoplasmic reticulum. Among its many functions, the endoplasmic reticulum folds and modifies newly formed proteins so they have the correct 3-dimensional shape. The SIL1 protein plays a role in the process of protein folding.

SIL1 gene mutations result in the production of a protein that has little or no activity. A lack of SIL1 protein is thought to impair protein folding, which could disrupt protein transport and cause proteins to accumulate in the endoplasmic reticulum. This accumulation likely damages and destroys cells in many different tissues, leading to ataxia, myopathy, and the other features of Marinesco-Sjögren syndrome.

Approximately one-third of people with Marinesco-Sjögren syndrome do not have identified mutations in the SIL1 gene. In these cases, the cause of the condition is unknown.

Inheritance and family implications

From: MedlinePlus Genetics, National Library of Medicine

This condition is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition.

How common is it?

From: MedlinePlus Genetics, National Library of Medicine

Marinesco-Sjögren syndrome appears to be a rare condition. More than 100 cases have been reported worldwide.

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 aldolase level · Very frequent (99-80%)

An abnormal concentration of aldolase in the serum. Aldolase is an enzyme responsible for converting fructose 1,6-bisphosphate into the triose phosphates dihydroxyacetone phosphate and glyceraldehyde 3-phosphate.

Abnormal circulating creatine kinase concentration · Very frequent (99-80%)

Any deviation from the normal activity of creatine kinase in the blood circulation.

Abnormal lactate dehydrogenase activity · Very frequent (99-80%)

A deviation from the normal serum concentration/activity of lactate dehydrogenase (LDH), which catalyzes the reduction of pyruvate to form lactate.

Abnormality of speech or vocalization · Very frequent (99-80%)

An abnormality in the sound (volume) or cadence (rate) of speech.

Abnormality of the cerebellar vermis · Very frequent (99-80%)

An anomaly of the vermis of cerebellum.

Aplasia/Hypoplasia involving the skeletal musculature · Very frequent (99-80%)

Absence or underdevelopment of the musculature.

Ataxia · Very frequent (99-80%)

Ataxia refers to impaired coordination of voluntary muscle movement. Cerebellar ataxia refers to ataxia due to dysfunction of the cerebellum. This causes a variety of elementary neurological deficits including asynergy (lack of coordination between muscles, limbs and joints), dysmetria (lack of ability to judge distances that can lead to under- or overshoot in grasping movements), and dysdiadochokinesia (inability to perform rapid movements requiring antagonizing muscle groups to be switched on and off repeatedly).

Cataract · Very frequent (99-80%)

A cataract is an opacity or clouding that develops in the crystalline lens of the eye or in its capsule.

Cerebellar hypoplasia · Very frequent (99-80%)

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

Dysarthria · Very frequent (99-80%)

Dysarthric speech is a general description referring to a neurological speech disorder characterized by poor articulation. Depending on the involved neurological structures, dysarthria may be further classified as spastic, flaccid, ataxic, hyperkinetic and hypokinetic, or mixed.

Dysphonia · Very frequent (99-80%)

Difficulty in speaking due to a physical disorder of the mouth, tongue, throat, or vocal cords. Associated with a known physical or neurological cause.

External genital hypoplasia · Very frequent (99-80%)

Underdevelopment of part or all of the external reproductive organs.

Global developmental delay · Very frequent (99-80%)

A delay in the achievement of motor or mental milestones in the domains of development of a child, including motor skills, speech and language, cognitive skills, and social and emotional skills. This term should only be used to describe children younger than five years of age.

Hypogonadism · Very frequent (99-80%)

A decreased functionality of the gonad.

Other findings in the same source

From: Orphanet

Additional reported features include Hypotonia (Very frequent (99-80%)); Intellectual disability (Very frequent (99-80%)); Myopathy (Very frequent (99-80%)); Severe short stature (Very frequent (99-80%)); Specific learning disability (Very frequent (99-80%)); Strabismus (Very frequent (99-80%)); Abnormal metacarpal morphology (Frequent (79-30%)); Abnormality of finger (Frequent (79-30%)); Avascular necrosis of the capital femoral epiphysis (Frequent (79-30%)); Brachydactyly (Frequent (79-30%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Marinesco-Sjögren syndrome is Neurology, with a neurologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

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 nervous-system findings help explain the symptoms?
• Would an assessment of walking, communication or daily function be helpful?
• Are rehabilitation or other specialist services relevant?

Treatment discussions and follow-up

The material gathered for this draft does not provide a complete condition-specific treatment pathway for Marinesco-Sjögren 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.