Icahn School of Medicine at Mount Sinai
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Genetic Testing Lab

Test Catalog Molecular Genetics Laboratory Congenital Erythropoietic Porphyria

Congenital Erythropoietic Porphyria

Test Description:

CEP is a deficiency of the enzyme uroporphyrinogen III synthase (URO-synthase), due to mutations, or changes, in the UROS gene. The disorder is autosomal recessive. CEP is one of the most severe porphyrias, symptoms usually begin soon after birth or in early childhood. Some severe cases have been diagnosed before birth as a cause of anemia and fluid accumulation in the fetus (fetal hydrops). Less severe cases may occur in adults in association with another bone marrow condition.

Skin photosensitivity results in severe blistering and scarring, often with mutilation and loss of facial features and fingers. Increased hair growth (hypertrichosis) on sun-exposed skin, brownish-colored teeth (erythrodontia), and reddish-colored urine are common. There may be bone fragility due to expansion of the bone marrow and vitamin deficiencies, especially vitamin D. Red blood cells have a shortened life-span, and mild or severe hemolytic anemia often results. Synthesis of heme and hemoglobin is actually increased to compensate for the shortened red blood cell survival and is associated with splenomegaly. Bacteria may infect the damaged skin and contribute to mutilation and scarring.

DNA analysis of the UROS gene is performed by full gene sequencing of all exons (coding regions), 20-30 base pairs into the introns (including splice sites), and the promoter region. This methodology should identify >99% of gene mutations listed in the Human Gene Mutation Database as well as novel mutations.

Specimen Requirements:
Two 10 mL EDTA (lavendar top) tubes and one 10 mL ACD (yellow top) tube. Two to three confluent T-25 flasks of cultured cells and one control flask are required for prenatal samples.

Shipping: Send at room temperature.

Turnaround Time: 14 days

CPT Codes: 83891, 83898x10, 83904x4, 83912

Consent Form: Porphyria Genetic Testing Consent [PDF]

Requisition Form: Porphyria Testing Requisition [PDF]

Prior to ordering prenatal testing, please contact our laboratory at 212-241-7518 to discuss.