Introduction Causes and demographics Clinical features Diagnosis Treatment
Majeed syndrome (MIM609628) is a very rare inherited autoinflammatory condition that presents in early childhood with chronic recurrent multifocal osteomyelitis (CRMO, or inflamed bones) and congenital dyserythropoietic anaemia (CDA, or anaemia due to inadequate manufacture of red cells by the bone marrow). Transient neutrophilic skin inflammation can occur, often resembling Sweet disease, in which biopsy reveals many polymorphonuclear neutrophil white blood cells.
Majeed syndrome is an autosomal recessive genetic condition, meaning two copies of the mutated gene are required, one from each carrier parent.
The gene altered in Majeed syndrome is called LPIN2, located on chromosome 18p11.31, encoding the Lipin 2 protein. Homozygotes (two copies of the same mutation) and compound heterozygotes (two different mutations affecting the same gene) have been identified. Nonsense and missense mutations have been found. The incidence of such gene mutations has been estimated to be 1 in 35,000 in an ethnically-matched population, but have not been detected in other populations. Other missense mutations in this gene have been reported in psoriasis. Lipin 2 is an enzyme involved in lipid (fat) metabolism. The mechanism of disease is so far unknown, but probably involves the innate immune system.
Only a small number of families have so far been identified with Majeed syndrome, and all have come from the Middle East. The rate of carriage of the mutations in Arab populations would predict this syndrome should be seen more commonly. It has therefore been postulated that it is under-diagnosed.
Clinical features develop in early childhood, no later than 2 years of age. The youngest reported onset has been at 3 weeks of age.
Majeed syndrome presents clinically as acute episodes of fever, pain and joint swelling that last several days, with 1-3 attacks per month.
The cardinal features of Majeed syndrome are:
Other inconsistent features reported include:
Involvement of the bones results in:
Quality of life can be poor due to:
It is possible carriers may develop the skin features alone, such as psoriasis and pustulosis, although the numbers are too small to be sure yet.
Diagnosis of CRMO is based on:
LPIN2 gene mutations can be identified on molecular genetic testing. This is the only gene so far found to be affected in Majeed syndrome.
X-Rays: typical lesions are found in the metaphyses of long bones as irregular radiolucent areas (osteolysis) surrounded by increased radiodensity (sclerosis).
Skeletal scans: increased uptake of Tc-99 or Ga-67 in inflammatory lesions and can detect asymptomatic lesions.
MRI: is the most sensitive investigation for active bone lesions especially in the vertebrae.
Bone biopsy: histology shows nonspecific inflammation with granulocytes.
Bone marrow biopsy: increased erythropoiesis including dyserythropoiesis with binucleated and trinucleated normoblasts.
Skin biopsy: intraepidermal neutrophil abscesses
Cultures: from bone, bone marrow, blood and skin are always negative
Blood tests:
Majeed syndrome must be distinguished from the distinct clinical entity Chronic Recurrent Multifocal Osteomyelitis (CRMO, MIM 259680), which is usually a sporadic condition but has also been reported in families. It typically begins later in childhood (onset 4-14 years) and usually resolves. Episodes usually occur less frequently with longer periods of remission between attacks than have been reported in Majeed syndrome. It is not associated with anaemia although the skin can be involved (psoriasis, palmoplantar pustulosis, Sweet syndrome), as can joints and bowel.
For the osteomyelitis:
For the anaemia:
For the skin:
Prenatal testing can be considered in subsequent pregnancies as siblings of an affected child have a 25% chance of also developing the syndrome and a 50% chance of being a carrier for the mutated gene. Testing can only be done if the actual mutation has been identified in the affected child. All children of an affected individual must be carriers for the syndrome.
