Victoria Parera, Maria Victoria Rossetti, Viviana Melito & Alcira Batlle

Centro de Investigaciones sobre Porfirinas y Porfirias (CIPYP) - CONICET and University of Buenos Aires

Congenital Erythropoietic Porphyria (CEP) or Gunther’s disease is an extremely rare metabolic disorder. CEP develops as a consequence of diminished activity of Uroporphyrinogen III Sinthetase (UROIII-S) which catalyses the synthesis of the physiological isomer Uroporphyrinogen III in Heme pathway. Large amounts of isomer I are accumulated and oxidized to Uroporphyrin I (URO I) producing red blood cells lysis and releasing URO I content which is excreted in urine and faeces.

Clinical manifestations including severe cutaneous lesions of exposed areas that could lead to tissues mutilation, hypertrichosis, alopecy, erythrodontia, are presented since birth. However later onset has also been described in 12 patients.

This report presents 3 cases of infantil CEP and 1 adult case in a 55 years old man. Urinary porphyrins excretion ranged between 37,000 and 59,500 mg/24 h (NV: < 250 mg/ 24 h). Fecal porphyrins were between 880 and 5,250 mg/g (NV: <130 mg/g) and plasmatic porphyrins between 5.80 and 11.50 (NV: < 1.30). HPLC analysis of urinary porphyrins showed a profile according to a typical CEP pattern (96-98% UROI – 2-4% UROIII).

UROIIII-S activity assayed in one of the children and in the adult revealed that the ability of the enzyme in converting isomer type I to III is diminished between 25-44%; nevertheless this value is greater than expected taking into account the autosomical recessive character of the pathology, these findings are in accordance with the mild clinical manifestation observed in both patients.