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.

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.

Normal Function

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, which are the main source of stored energy in cells. Triglycerides are the major component of cell structures called lipid droplets (also called adiposomes). The ATGL enzyme is found on the surface of lipid droplets. When activated, the ATGL enzyme breaks down triglycerides to provide energy for the body.

Health Conditions Related to Genetic Changes

Neutral lipid storage disease with myopathy

At least five mutations in the PNPLA2 gene have been found to cause neutral lipid storage disease with myopathy. Some of these mutations cause the enzyme to function abnormally. Other mutations prevent the enzyme from ever reaching lipid droplets, so it is unable to interact with triglycerides. Any disruption in the breakdown of triglycerides leads to the accumulation of these fats in muscle and other tissues throughout the body, resulting in the signs and symptoms of neutral lipid storage disease with myopathy.

Other Names for This Gene

• adipose triglyceride lipase
• ATGL
• desnutrin
• FP17548
• patatin-like phospholipase domain containing 2
• PLPL2_HUMAN
• transport-secretion protein 2.2
• triglyceride hydrolase
• TTS-2.2
• TTS2

Genomic Location

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.

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