INVESTIGADORES
FERREIRA GOMES Mariela Soledad
congresos y reuniones científicas
Título:
VARIEGATE PORPHYRIA IN ARGENTINEAN POPULATION. CHARACTERIZARION OF THE MOLECULAR DEFECT
Autor/es:
MARIELA FERREIRA GOMES; VICTORIA PARERA; ALCIRA BATLLE ; MARIA VICTORIA ROSSETTI
Reunión:
Congreso; Cape Town Porphyrins and Porphyrias 2005; 2005
Resumen:
Variegate
Porhyria (VP) is a low penetrante, autosomal dominant disorder of heme
biosynthesis that results from partial deficiency of Protoporphyrinogen oxidase
(PPOX). At present 120 diferent mutations in PPOX gene causing VP have been
described. VP prevalence is much higher in South Africa (1:300) due to a
founder effect. In Europe, the higher prevalences are found in Finland
(2:100.000) and Sweden (1:100.000).
Up date,
about 60 individuals representing 49 apparently unrelated Argentinean families
have been biochemically diagnosed with VP, giving a prevalence of approximately
1:600.000 inhabitants.
Genetic
studies have been performed in 15 of these families. Sequencing analysis
indentified 8 different mutations in 7 of 12 probands. In order 3 families the
mutation was not yet found. Three nucleotide substitutions (R168H, L178V and
H106P), a small deletion (delG745), a small insertion (insT1320) and 3 splicing
defects (G810®A,
G749®A,
g3912®c)
were found. R168H and delG745 mutations have been previously reported. The
occurrence of the missense mutation R168H have been reported in American
(Chile), German and Dutch families, representing the first demostrable hot
spot mutation in VP. All mutation were
each specific for an individual family
except the small insertion (insT1320) which was found in 5 unrelated families
suggesting that it might represent a common mutation in Argentina. So,
the inicial screening to elucidate the genetic defect in VP patients from
Argentina includes the insertion search. Haplotype analysis should still be
performed to elucidate if the high occurrence of this mutation would be due to
a founder effect.
Molecular
analysis in those available family members revealed 5 adults and 4 children who
were silent carriers of VP trait assessing that molecular techniques represent
the most accurate approach to identify unaffected carriers and to also provide
accurate genetic counsenling for asymptomatic affected individuals.