Neutral lipid storage disease with myopathy

What it is, symptoms and effects

From: MedlinePlus Genetics, National Library of Medicine

Neutral lipid storage disease with myopathy is a condition in which fats (lipids) are stored abnormally in organs and tissues throughout the body. People with this condition have muscle weakness (myopathy) due to the accumulation of fats in muscle tissue. Other features of this condition may include a fatty liver, a weakened and enlarged heart (cardiomyopathy), inflammation of the pancreas (pancreatitis), reduced thyroid activity (hypothyroidism), and type 2 diabetes (the most common form of diabetes). Signs and symptoms of neutral lipid storage disease with myopathy vary greatly among affected individuals.

Causes and biological mechanisms

From: MedlinePlus Genetics, National Library of Medicine

Mutations in the PNPLA2 gene cause neutral lipid storage disease with myopathy. The PNPLA2 gene provides instructions for making an enzyme called adipose triglyceride lipase (ATGL). The ATGL enzyme plays a role in breaking down fats called triglycerides. Triglycerides are an important source of stored energy in cells. These fats must be broken down into simpler molecules called fatty acids before they can be used for energy.

PNPLA2 gene mutations impair the ATGL enzyme's ability to break down triglycerides. These triglycerides then accumulate in muscle and tissues throughout the body, resulting in the signs and symptoms of neutral lipid storage disease with myopathy.

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

Neutral lipid storage disease with myopathy is a rare condition; its incidence is unknown.

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.

Fatty replacement of skeletal muscle · Very frequent (99-80%)

Muscle fibers degeneration resulting in fatty replacement of skeletal muscle fibers

Increased intramyocellular lipid droplets · Very frequent (99-80%)

An abnormal increase in intracellular lipid droplets In a muscle. The number and size of these drops can increase with somd disorders of lipid metabolism affecting muscle. See PMID 20691590 for histological images.

Progressive proximal muscle weakness · Very frequent (99-80%)

Lack of strength of the proximal muscles that becomes progressively more severe.

Shoulder girdle muscle weakness · Very frequent (99-80%)

The shoulder, or pectoral, girdle is composed of the clavicles and the scapulae. Shoulder-girdle weakness refers to lack of strength of the muscles attaching to these bones, that is, lack of strength of the muscles around the shoulders.

Abnormal circulating creatine kinase concentration · Frequent (79-30%)

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

Cardiomyopathy · Frequent (79-30%)

A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality.

Difficulty running · Frequent (79-30%)

Reduced ability to run.

Easy fatigability · Frequent (79-30%)

Increased susceptibility to fatigue.

Elevated circulating hepatic transaminase concentration · Frequent (79-30%)

Elevations of the levels of SGOT and SGPT in the serum. SGOT (serum glutamic oxaloacetic transaminase) and SGPT (serum glutamic pyruvic transaminase) are transaminases primarily found in the liver and heart and are released into the bloodstream as the result of liver or heart damage. SGOT and SGPT are used clinically mainly as markers of liver damage.

Fasciculations · Frequent (79-30%)

Fasciculations are observed as small, local, involuntary muscle contractions (twitching) visible under the skin. Fasciculations result from increased irritability of an axon (which in turn is often a manifestation of disease of a motor neuron). This leads to sporadic discharges of all the muscle fibers controlled by the axon in isolation from other motor units.

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).

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.

Hepatic steatosis · Frequent (79-30%)

Steatosis is a term used to denote lipid accumulation within hepatocytes.

Other findings in the same source

From: Orphanet

Additional reported features include Hypertriglyceridemia (Frequent (79-30%)); Increased circulating lactate dehydrogenase concentration (Frequent (79-30%)); Motor delay (Frequent (79-30%)); Myalgia (Frequent (79-30%)); Myopathy (Frequent (79-30%)); Pelvic girdle muscle weakness (Frequent (79-30%)); Very long chain fatty acid accumulation (Frequent (79-30%)); Areflexia (Occasional (29-5%)); Chronic pancreatitis (Occasional (29-5%)); Congestive heart failure (Occasional (29-5%)). This is a selected summary, not a complete description of the condition.

Which doctor should you see?

The suggested department for discussing Neutral lipid storage disease with myopathy 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 Neutral lipid storage disease with myopathy. 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.