my personal edition > lupus > news


  E-Mail this DGDispatch to a colleague

DGDispatch

Systemic Lupus Erythematosus May Be Related to Prolidase Insufficiency

By Maggie Schwarz

WASHINGTON, DC -- November 13, 2006 -- For the first time, a prolidase gene mutation concomitant with systemic lupus erythematosus (SLE) has been identified, according to researchers speaking here at the American College of Rheumatology - Association of Rheumatology Health Professionals Annual Scientific Meeting (ACR-ARHP).

Anil D'souza, PhD, research associate, Oklahoma Medical Research Foundation, Oklahoma City, Oklahoma, reported that a deficiency was discovered in 1 of a cohort of 5 Amish children with SLE.

Prolidase is a ubiquitous cytosolic enzyme involved in the digestion and metabolism of protein which specifically cleaves iminodipeptides containing C-terminal prolyl or hydroxyprolyl residues, thus playing an important role in the final stage of degradation of collagen, which is particularly rich in these amino acids.

Genetic deficiency of prolidase leads to severe problems in child development, including abnormal joints, skin lesions, skin cancer and mental retardation. Many immunological abnormalities also occur and are associated with immune dysfunction. Hepatomegaly, thrombocytopenia and skin rashes are also seen.

Of the 5 children studied, 2 have died.

An assay was developed to test for prolidase deficiency. Polymerase chain reaction conditions were standardized to amplify the exon- 11 region of the prolidase gene. The subject found to have both SLE and prolidase deficiency was a 2.5 year-old male who had been on oral steroids for 2 to 3 months for a skin problem and presented with fever of unknown etiology. His blood cultures were negative. The boy met at least 4 ACR criteria and was classified as having SLE.

The child's clinical work-up was as follows: erythrocyte sedimentation rate, 45; C-reactive protein, 4.5; antineutrophil antibodies, 1:1080 (positive) with speckled pattern; positive dsDNA; uric acid with 2+ protein and serum albumin, 2.9.

A gene mutation was seen on exon 11. The group suggested that a single copy of a gene which causes a rare autosomal recessive genetic illness such as prolidase deficiency might be related to a genetically complicated autoimmune disease such as SLE.

The investigators are not examining SLE samples to determine whether prolidase deficiency correlates with SLE outside of the Amish community.


[Presentation title: Prolidase Deficiency in Systemic Lupus Erythematosus. Abstract 629]

E-Mail this DGDispatch to a colleague

To print, use this version