Porphyria Cutanea Tarda in Argentina. An update.

VARELA, LAURA; MENDEZ MANUEL; CERBINO, GABRIELA; COLOMBO, FEDERICO; MELITO, VIVIANA; BUZALEH ANA MARIA; PARERA VICTORIA

Mar del Plata

Congreso; CONGRESO DE BIOCIENCIAS 2022; 2022

Sociedad Argentina de Investigación Clínica

Porphyria Cutanea Tarda (PCT) is the most common porphyria inArgentina (prevalence 1:20,000). There are two main types: PCT-A(acquired, sporadic or type I) and PCT-H (hereditary or type II).Type I is the most common form of PCT (70-80%) and the deficiencyin Uroporphyrinogen decarboxylase (URO-D) is restricted tothe liver. In PCT type II blood URO-D activity is reduced by 50%.The manifestation of PCT is associated with triggering factors: alcoholconsumption, hormones and iron overload. The associationbetween PCT and other pathologies is remarkable: hereditary haemochromatosis(HH), HCV and HIV. The aim of this study was toanalyze the patients diagnosed in CIPYP with PCT to date to evaluatethe incidence of the different types of PCT in our population.All patients signed the Informed consent. Among 2230 PCT casesanalyzed, 92% were PCT-A; 79% male and 21% female, in a 3.7:1ratio. In the PCT-H cohort, 179 were symptomatic and 43 were latentin a 1.3:1 male:female ratio in both cases. 16.4% of the PCTswere HIV+ and 34% were HCV+. Only 4.3% were HH, 31.6% carriedp.H63D (26.5% heterozygous, 5.1% homozygous). 6.8% carriedthe p.C282Y mutation (5.1% heterozygous, 1.7% homozygous)and 2.6% were heterozygous for both mutations. In the 84 unrelatedPCT-H families, 45 different pathogenic variants were found, ofwhich 16 were reported for the first time in CIPYP. In 23 families, thec.10-12insA variant (27%) was detected, being the most frequent in the country. The second was p.M165R (8%) and in third placep.N304K (7%), which together represent 38% of the allelic variantscharacterized. We also diagnosed 25 cases of childhood PCT, carryingc.10-12insA (8 cases) and p.M165R (2 cases). Although PCT-His inherited in an autosomal dominant manner with low penetrance,there are multiple triggering factors. Genetic diagnosis is of utmostimportance as it allows counselling about contact with such agentsto avoid the clinical expression in latent cases.