Farber disease
Synonyms and keywords:  Farber lipogranulomatosis; ceramidase deficiency; disseminated lipogranulomatosis; acid ceramidase deficiency; N-Laurylsphingosine deacylase deficiency; Farber's disease

# Overview
Farber disease describes a group of rare autosomal recessive disorders that cause an accumulation of lipids in the joints, tissues and central nervous system.

# Historical Perspective
Farber disease is named for Sidney Farber.

# Classification
Researchers have described seven types of Farber lipogranulomatosis based on their characteristic features.

# Pathophysiology
Farber disease is a rare inherited condition involving the breakdown and use of fats in the body (lipid metabolism).  In affected individuals, harmful amounts of lipids accumulate in cells and tissues throughout the body, particularly around the joints. 
The brain, liver, heart and kidneys are the organs commonly affected in this disorder.

## Genetics
This disease is associated with a mutation in ASAH1 gene.  It has an autosomal recessive pattern of inheritance.
The ASAH1 gene provides instructions for making an enzyme called acid ceramidase. This enzyme is found in the lysosomes (compartments that digest and recycle materials in the cell), where it breaks down fats called ceramides so that these fats can be used by the body. Ceramides make up one subtype of a group of fats called sphingolipids.The ceramide accumulation in Farber lipogranulomatosis results from an inability to break down ceramides in the lysosomes.
Mutations in the ASAH1 gene lead to a shortage of functional acid ceramidase, which prevents lysosomes from breaking down ceramides properly. Without the activity of acid ceramidase, ceramides can build up in the lysosomes of cells and tissues in the lung, liver, colon, muscles used for movement (skeletal muscles), cartilage, and bone. This buildup causes the signs and symptoms of Farber lipogranulomatosis, and the severity of the disease depends on the amount of ceramide accumulation.

# Epidemiology and Demographics
- About 80 individuals affected by this condition have been reported worldwide.
- Infants are affected by this disorder.
- The disorder affects both males and females.

# Natural History, Complications and Prognosis
- Disease onset is typically in early infancy but may occur later in life.  Children who have the classic form of Farber disease develop neurological symptoms within the first few weeks of life.
- Most children with the disease die by age 2, usually from lung disease.  In one of the most severe forms of the disease, an enlarged liver and spleen (hepatosplenomegaly) can be diagnosed soon after birth.  Children born with this form of the disease usually die within 6 months.

# Daignosis

## Symptoms
- Moderately impaired mental ability
- Problems with swallowing.  The  Other symptoms may include
- Vomiting
- Arthritis
- Hoarseness
- Breathing difficulty

## Physical Examination

### Skin
- Xanthemas which thicken around joints as the disease progresses
- Lipogranulomas - small lumps of fat in the skin

### Head
- Swollen lymph nodes

### Abdomen
- Hepatosplenomegaly

### Extremities
- Swollen joints
- Joint contractures (chronic shortening of muscles or tendons around joints)

### Neurologic
- Impaired intellectual ability

# Treatment
- There is no specific treatment for Farber disease.
- Corticosteroids may be prescribed to relieve pain.
- Bone marrow transplants may improve granulomas (small masses of inflamed tissue) on patients with little or no lung or nervous system complications.
- Older patients may have granulomas surgically reduced or removed.