Cytoreductive therapy has been the standard of care for CGL for decades, but it has been proven to be ineffective in a small proportion of patients and does not affect the underlying cause of the disease. Recombinant IFN-alpha, an immunomodulatory agent, was shown to produce clinical remission in a small percentage of patients.
Symptoms
CGL disease is characterized by metabolic complications related to insulin resistance. Some infants with the disease develop a characteristic skin condition called acanthosis nigricans. This skin disease causes abnormal hyperkeratosis and hyperpigmentation. It can also cause glucose intolerance and hypertriglyceridemia. Some people with CGL develop extreme hypertriglyceridemia and chylomicronemia.
The severity of CGL depends on the mutation type. There are four major types of CGL: type 1, type 2, and type 4. Type 1 CGL patients have preserved mechanical adipose tissue and lack metabolic fat. Type 2 CGL patients also show the absence of bone marrow fat. Type 3 and type 4 CGL patients show bone marrow fat preservation.
Patients with CGL may also develop polycystic ovary syndrome (PCOS), characterized by an imbalance of female sex hormones and too much androgen. PCOS also results in irregular menstruation and oily skin. Females with PCOS may exhibit signs of hirsutism. Their upper lip may become hairy. In a few cases, a CGL patient may also develop morphological defects in his sperms.
Type 4 CGL causes abnormal thickening of the muscle walls of the left lower chamber of the heart. This obstructs blood flow into and out of the heart. Some individuals with this disorder do not experience any symptoms, but others can develop shortness of breath on exertion, fatigue, and excessive sweating. Some people with this condition also experience chest pain, irregular heartbeats, and dizziness. If left untreated, hypertrophic cardiomyopathy can become life-threatening.
There are several types of CGL, each with different symptoms. Types 1 and 2 have less severe forms of the disease than type 4. Both types have an overall lack of adipose tissue. Affected individuals have a herculean appearance and may have acromegaloid facies. They often experience vitamin D deficiency. In addition, some individuals have a large liver and spleen.
There are some genetic tests that can help confirm a diagnosis. A homozygous mutation of the BSCL2 gene causes CGL. It may also be associated with epilepsy.
Diagnosis
Diagnosis of CGL disease is usually made using family history and phenotypic traits. The most common types of the disease are type 1 and type 2. Type 2 is more common and accounts for over 95% of the cases. Type 3 is rare, with only a few cases reported. Type 4 is more rare, with around 30 cases reported. Type 1 and type 2 hands are depicted in Figure 2. In type 1 patients, there is no evidence of loss of mechanical fat tissue, and in type 2 the loss of fat is noticeable.
Patients with type 2 diabetes usually die before reaching their 30s. Causes of death may include liver disease, infections, and diabetes. Diagnosis of CGL disease is made using clinical data, including the presence of acanthosis nigricans and a reduced amount of total body fat. Blood tests can reveal hypertriglyceridemia, and imaging tests may show ectopic fat deposits. Lastly, a DXA scan can show the presence of low body fat and high bone density.
Although type 1 CGL is more common, some patients with this disease also have type 2. Type 2 CGL is caused by a mutation in the BSCL2 gene. Patients with this gene are at a high risk of developing diabetes. The symptoms of type 2 CGL can vary, but they are usually mild to moderate.
The symptoms of CGL disease are generally similar to those of AGL. During childhood, CGL patients exhibit an absence of fat. They often have prominent muscles and a voracious appetite. In rare cases, the patient may also have acanthosis nigricans, a dark velvety skin disease. Some cases also feature an abnormal liver and spleen.
Diagnosis of CGL disease should include a bone scan. A bone scan may be used to detect the disease in its early stages. The patient should be evaluated in a hospital or clinic. Patients should be monitored with imaging and lifestyle modifications. Surgical management is more difficult in patients with CGL. Patients with CGL disease may have other conditions, including insulin resistance, cardiac and hepatic dysfunction.
In addition to metabolic complications, patients with CGL disease may also experience seizures. The primary symptom is an inability to store triglycerides in adipose tissue. Patients with this disease should be provided with psychological support, a low-fat diet, and increased physical activity.
Treatment
CGL disease treatment involves strict dietary control, which is a challenge due to an increase in appetite. Physical activity is also recommended to improve control of comorbidities. However, it should be noted that exercise should not be initiated in severe cases of cardiomyopathy. Patients with CGL should consult their doctors to determine a treatment plan that will work best for them.
Children with CGL may present with voracious appetite, increased metabolic rate, and accelerated linear growth. They may also show early onset of puberty and mental retardation. Seipin mutations reduce the stability of the protein, which results in reduced oligomerization. In addition, patients with CGL2 may develop cardiomyopathy.
In adults, CGL may cause complications, including problems with the heart, blood vessels, kidneys, and bones. The condition can also lead to diabetes and can be difficult to control. Some people with CGL may have extra hair on the upper lip and chin. The genetics of CGL can be passed on to children, and treatment for CGL requires special testing to diagnose the condition and to determine the appropriate therapy.
Pediatric CGL patients can undergo plastic surgery to improve their facial appearance. Doctors can use skin grafts taken from the thighs, belly, or scalp. Alternatively, they may use implants and injections of fillers to improve facial features. In some cases, the condition can be treated with hormone replacement therapy. If the skin is dark or has patches of FPL, prescription creams may be used to lighten it. However, it is important to remember that over-the-counter bleaches can be irritating to the skin.
Treatment for CGL disease varies according to the type of mutation that causes the disorder. For example, CAV1 mutations impair the production of adipocytes, and this inhibits their differentiation. As a result, patients with CAV1 mutations often experience a reduced fat mass. Moreover, they experience hypomagnesemia and decreased bone density. These genetic variations are rare in CGL patients. It is therefore important to follow a genetic testing regimen for CGL.
CGL disease treatment is multidisciplinary and should include dietary control, medication, and psychosocial support. Dietary control and metreleptin therapy are important in long-term holistic management of CGL. In some cases, the family should also be involved in the treatment process.
Genetics
CGL disease is caused by mutations in genes related to adipocyte differentiation and metabolism. Genetic analysis of a single female patient with CGL showed a homozygous point mutation in the c-fos gene promoter. This gene encodes a transcription factor necessary for the differentiation of adipocytes. Neither of her parents carried the homozygous variant. The patient presented with generalized lipoatrophy and myopathy from childhood. She developed bilateral cataracts by the time she was 22 years old, hepatosplenomegaly, and hypertrichosis by the time she was 35 years old. The patient’s family history did not mention this genetic mutation, but she developed the disease during a hyperacute varicella infection.
Women with CGL disease may also experience polycystic ovary syndrome (PCOS). PCOS is characterized by an imbalance of female sex hormones. This condition can cause irregular menstruation and even the absence of menstruation. Other symptoms include oily skin and multiple cysts on the ovaries. Women with PCOS may also exhibit signs of hirsutism, which is an abnormal increase of hair growth on the upper lip.
Although genetic testing of CGL genes is not routinely performed in asymptomatic individuals, it is necessary for patients with the disease to undergo a genetic test. This test can identify the genes that cause CGL. The genetic test may help determine whether the patient is a carrier of the genes.
The mutations that cause CGL disease are usually caused by mutations in genes that control adipocytes’ metabolic activities. This disease can lead to metabolic complications later in life. Recent genetic studies of patients with CGL have provided important insights into the molecular mechanisms that regulate hypertriglyceridemia, extreme insulin resistance, and metabolic dysregulation. Patients with CGL often exhibit low levels of leptin and FFA. Excess triglyceride accumulation is the main cause of metabolic complications in CGL disease.
Inherited lipodystrophy can lead to serious health complications, including heart, liver, and kidney problems, as well as diabetes. It can also affect bones and the immune system. Symptoms of CGL can range from mild to severe.
