Partial Lipodystrophy

Partial lipodystrophy is a rare condition where the body loses fat tissue from specific areas such as the arms, legs, and buttocks, while fat may accumulate in other regions like the face, neck, and abdomen. This abnormal distribution of fat can lead to serious metabolic complications including diabetes, high triglycerides, and fatty liver disease.

Table of contents

• What is partial lipodystrophy
• Types of partial lipodystrophy
• Signs and symptoms
• Causes and genetics
• How common is the condition
• Diagnosis
• Treatment and management
• Metabolic complications
• Impact on quality of life

What is partial lipodystrophy

Partial lipodystrophy refers to a group of rare conditions where fat tissue (also called adipose tissue) is selectively lost from certain parts of the body. Unlike generalized lipodystrophy where fat loss affects the entire body, partial forms cause fat to disappear from specific regions while sometimes building up in others^[1][2].

Fat tissue plays important roles in the body beyond just storing energy. It cushions organs, helps regulate body temperature, and releases hormones that control how the body processes sugar and fats. When fat tissue is lost or distributed abnormally, it disrupts these vital functions and can lead to serious health problems^[2].

In partial lipodystrophy, fat loss typically affects the arms, legs, and buttocks, giving these areas a very muscular appearance. Meanwhile, excess fat often accumulates around the face, neck, between the shoulder blades, and inside the abdomen. This creates a distinctive body shape that can be quite noticeable^[1][3].

Familial partial lipodystrophy, FPLD, Acquired partial lipodystrophy, APL, Barraquer-Simons syndrome, Köbberling–Dunnigan syndrome

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Types of partial lipodystrophy

There are two main categories of partial lipodystrophy: genetic (also called familial) and acquired forms. Each category includes several subtypes with different characteristics^[2][5].

Familial partial lipodystrophy (FPLD) is inherited from parents and usually becomes noticeable around puberty. The most common form is Type 2, also known as Dunnigan disease. People appear normal at birth and throughout childhood, but fat gradually disappears from the limbs and trunk during adolescence. At least six different types of familial partial lipodystrophy have been identified, each caused by mutations in different genes^[1][5].

Acquired partial lipodystrophy (APL), also called Barraquer-Simons syndrome, typically develops during childhood at a median age of 7-8 years. It predominantly affects females and often occurs after a viral illness, most commonly measles. Fat loss usually begins in the face and gradually spreads downward to affect the neck, arms, and upper body. Some people may develop excess fat in the lower body, particularly around the hips, legs, and buttocks^[4][10].

Signs and symptoms

The most visible sign of partial lipodystrophy is the abnormal distribution of body fat. In familial forms, fat loss from the arms and legs creates a very muscular appearance, while the face may become fuller and rounder. Some people develop what doctors call a “cushingoid” appearance, meaning they look similar to people with a hormonal disorder called Cushing disease^[1].

The skin in body folds and creases often becomes thick, dark, and velvety—a condition called acanthosis nigricans. This happens because of high insulin levels in the bloodstream and typically appears on the neck, armpits, and where the legs meet the trunk^[1].

Women with partial lipodystrophy frequently develop reproductive problems after puberty. These may include irregular or absent menstrual periods, excessive body hair (particularly on the face), and difficulty becoming pregnant. Some women develop polycystic ovary syndrome (PCOS), which causes multiple cysts on the ovaries^[1][5].

Physical changes can appear at different times depending on the type. In familial forms, changes typically become apparent around puberty in females, often later in males. In acquired forms, fat loss may progress slowly over months or years, or occur more rapidly over just a few weeks^[4][14].

• Subcutaneous tissue (fat under the skin)
• Liver
• Pancreas
• Ovaries
• Kidneys
• Heart

Causes and genetics

Familial partial lipodystrophy is caused by mutations in several different genes. The most common form, Type 2, results from mutations in the LMNA gene. This gene provides instructions for making proteins called lamins, which are important for the structure and function of cell nuclei. More than 500 cases of Type 2 familial partial lipodystrophy have been reported in medical literature^[1][5].

Other genes associated with familial partial lipodystrophy include PPARG (causing Type 3), AKT2, PLIN1 (causing Type 4), LIPE (causing Type 6), and CIDEC (causing Type 5). Each of these genes plays important roles in fat cell development, structure, or function. When mutations occur, they impair the body’s ability to properly store and use fat^[1][5][7].

Most familial forms are inherited in an autosomal dominant pattern, meaning only one mutated gene from one parent can cause the condition. However, Type 5 is inherited in an autosomal recessive pattern, requiring mutations from both parents^[5][8].

The cause of acquired partial lipodystrophy is less clear. It has been associated with activation of the complement system—a part of the immune system that helps fight infections. Many patients have low levels of a protein called C3 and the presence of autoantibodies. The condition often follows viral illnesses or occurs alongside autoimmune diseases^[4][16].

How common is the condition

Partial lipodystrophy is extremely rare. Familial partial lipodystrophy affects an estimated 1 in 1 million people overall, though this is likely an underestimate because many cases go unrecognized^[1][5].

Approximately 250 cases of acquired partial lipodystrophy have been reported in English medical literature since the condition was first described in the late 1800s. This form predominantly affects females, with women diagnosed about four times more often than men^[4].

Women tend to be diagnosed with familial partial lipodystrophy more frequently than men, probably because fat loss from the hips and limbs is more easily recognized in women, and complications such as diabetes and high triglycerides occur more commonly in women. However, this may reflect underdiagnosis in men rather than true differences in occurrence^[1].

Diagnosis

Diagnosing partial lipodystrophy begins with a careful physical examination to assess body fat distribution. Doctors look for characteristic patterns of fat loss and accumulation. Because the condition is rare and can be easily missed, many people experience delays in receiving an accurate diagnosis^[11][14].

Several imaging techniques can help measure fat distribution. These include dual-energy X-ray absorptiometry (DEXA), magnetic resonance imaging (MRI), and computed tomography (CT) scans. These tests create detailed pictures that show exactly where fat is present or absent in the body^[5][11].

Blood tests are essential for diagnosis and reveal important information about metabolism. Doctors check levels of triglycerides, cholesterol, blood sugar, insulin, and hormones such as leptin and adiponectin. High triglycerides and low levels of HDL cholesterol (the “good” cholesterol) are common findings. Many people have insulin resistance or diabetes^[5][11].

Genetic testing can confirm familial forms by identifying mutations in known lipodystrophy genes. This testing is particularly helpful for family members who may be at risk. However, many patients with lipodystrophy do not have mutations in currently known genes, suggesting that other disease-causing genes remain to be discovered^[5][7].

For acquired forms, special laboratory tests can measure complement levels and look for autoantibodies. Liver enzyme levels should be checked, and ultrasound imaging of the liver can detect fatty liver disease. Body mass index is usually normal despite the abnormal fat distribution^[4][5].

Treatment and management

While there is no cure for partial lipodystrophy, several treatments can help manage symptoms and prevent complications. Treatment focuses on controlling blood sugar, reducing triglyceride levels, and addressing other metabolic problems^[2][11].

Lifestyle changes form the foundation of treatment. A low-fat diet is essential, with fat intake typically limited to no more than 30% of total calories, and sometimes as low as 15-20% when triglycerides are very high. The diet should emphasize complex carbohydrates and high-fiber foods. Regular physical activity is strongly encouraged^[3][15].

Diabetes is treated with standard medications, though people with lipodystrophy often need very high doses of insulin—sometimes more than 200 units per day. Even with these high doses, blood sugar control can be difficult to achieve. Other diabetes medications such as metformin are commonly used^[9][23].

High triglycerides are treated with medications called fibrates, along with fish oil supplements containing omega-3 fatty acids. Statins may be used to lower cholesterol. When triglycerides become extremely high (above 2000 mg/dL), very strict low-fat diets are necessary to prevent pancreatitis, a dangerous inflammation of the pancreas^[11][15].

Leptin replacement therapy with a medication called metreleptin has been approved in some countries for treating generalized lipodystrophy and certain cases of partial lipodystrophy. This treatment replaces the leptin hormone that is deficient due to fat loss. It can improve blood sugar control, reduce triglycerides, and decrease liver fat. However, it does not work equally well for all patients with partial lipodystrophy^[3][11][14].

Metabolic complications

The abnormal storage of fat in partial lipodystrophy leads to numerous metabolic problems. Many people develop insulin resistance, a condition where the body’s tissues cannot adequately respond to insulin, which normally helps regulate blood sugar levels. This resistance often progresses to diabetes mellitus^[1][3].

High levels of fats called triglycerides circulate in the bloodstream, a condition called hypertriglyceridemia. When triglyceride levels become very high, they can cause pancreatitis, which is painful and potentially life-threatening. Some patients have experienced triglyceride levels as high as 67 mmol/L (normal is below 1.7 mmol/L)^[1][20].

Fat accumulates abnormally in the liver, causing hepatic steatosis (fatty liver disease). This can lead to an enlarged liver and abnormal liver function. In some cases, it progresses to more serious conditions such as inflammation of the liver (steatohepatitis) or scarring (cirrhosis)^[1][5].

Cardiovascular problems are common, especially in Type 2 familial partial lipodystrophy. Some people develop abnormalities of the heart muscle (cardiomyopathy), coronary artery disease, and problems with the heart’s electrical system. High blood pressure is frequent. These complications contribute to an increased risk of heart attacks and strokes at younger ages than typical^[1][5][9].

In acquired partial lipodystrophy, about 20% of patients develop kidney disease called membranoproliferative glomerulonephritis. This serious complication affects kidney function and may cause protein to appear in the urine. It is more likely in patients who have low complement C3 levels^[4][16].

Insulin resistance
Diabetes mellitus
Hypertriglyceridemia
Pancreatitis
Hepatic steatosis
Coronary artery disease
Cardiomyopathy
Membranoproliferative glomerulonephritis
Polycystic ovary syndrome
Acanthosis nigricans

Impact on quality of life

Beyond the medical complications, partial lipodystrophy significantly affects quality of life and mental health. The visible changes in body shape can cause considerable distress, self-consciousness, and difficulties with self-image. People may feel uncomfortable in social situations or avoid activities where their body would be visible^[14][20].

Many people experience chronic fatigue that interferes with daily activities. Some report needing frequent naps to get through the day or struggling to stay alert at work. Muscle cramps, particularly in the calves, can be painful and limiting^[20].

The condition affects family life as well. Parents worry about their children inheriting the condition, and families cope with the stress of managing a chronic disease. The rarity of the condition can make people feel isolated, though connecting with others who have lipodystrophy through support groups can be helpful^[14][17][20].

Managing the condition requires ongoing medical care, frequent doctor visits, multiple medications, and strict dietary restrictions. This can be demanding and sometimes overwhelming. However, with proper treatment and support, many people with partial lipodystrophy lead full and productive lives^[11][14].