TFR2-related hereditary hemochromatosis as a frequent cause of primary iron overload in patients from Central-Southern Italy.
OBJECTIVE
Hereditary hemochromatosis (HH) is a common Mendelian disorder of iron metabolism. Eighty percent of northern Europeans descendant HH patients carry the same mutation (p.C282Y) in the HFE gene. Simultaneously, due to a founder effect, its frequency varies considerably between different populations. In Central-Southern Italy the prevalence of p.C282Y mutation is low and in several patients the disease has different causes. Four additional rarer forms have been described. Type 3 HH has been reported in about 50 families and no more than 30 TFR2 pathogenic mutations have been globally identified. The aim of this study is to assess the TFR2 role in non-HFE HH pathogenesis.


METHODS
TFR2 sequence analysis was performed on 45 Italian patients without HFE mutations.


RESULTS
This study revealed TFR2 biallelic pathogenic mutations in 7/45 (15.6%) individuals. Moreover monoallelic TFR2 deleterious defects (18%) or polymorphisms with unclear meaning (36%) were identified. Besides, we recognized 10 novel variants and 9 described changes.


CONCLUSIONS
We believe this to be the largest series of type 3 HH patients described so far. Present findings support the hypothesis of a main role of the TFR2 gene in HH pathogenesis in those regions, such as Central-Southern Italy, where the p.C282Y frequency is low.
Medical Genetics, Molecular Medicine Department, Sapienza University of Rome, San Camillo-Forlanini Hospital, Rome, Italy. Electronic address: francesca.clementina.radio@gmail.com.
Francesca Clementina
FC
Radio
Medical Genetics, Molecular Medicine Department, Sapienza University of Rome, San Camillo-Forlanini Hospital, Rome, Italy.
Silvia
S
Majore
Medical Genetics, Molecular Medicine Department, Sapienza University of Rome, San Camillo-Forlanini Hospital, Rome, Italy.
Francesco
F
Binni
Medical Genetics, Molecular Medicine Department, Sapienza University of Rome, San Camillo-Forlanini Hospital, Rome, Italy.
Michele
M
Valiante
Hematology Department, Catholic University of Sacro Cuore, Rome, Italy.
Bianca Maria
BM
Ricerca
Medical Genetics, Molecular Medicine Department, Sapienza University of Rome, San Camillo-Forlanini Hospital, Rome, Italy.
Carmelilia
C
De Bernardo
Healthcare Administration, S. Camillo-Formìlanini Hospital, Rome, Italy.
Aldo
A
Morrone
Medical Genetics, Molecular Medicine Department, Sapienza University of Rome, San Camillo-Forlanini Hospital, Rome, Italy.
Paola
P
Grammatico
D000483:Alleles; D001483:Base Sequence; D004252:DNA Mutational Analysis; D006432:Hemochromatosis / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007501:Iron / Q000378:metabolism; D019190:Iron Overload / Q000235:genetics / Q000378:metabolism; D007558:Italy; D009154:Mutation; D011990:Receptors, Transferrin / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism
D011990:Receptors, Transferrin; C503640:TFR2 protein, human; D007501:Iron
Hereditary hemochromatosis; Iron overload; Mediterranean area; Non-HFE hereditary hemochromatosis; Novel mutations; TFR2