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Incidence of Haemochromatosis in People of Italian Descent

Hereditary and Acquired Iron Overload

 

 

How Did I Get Haemochromatosis?

Haemochromatosis is primarily a genetic disorder, although it can be acquired through taking too many iron supplements or lots of blood transfusions.

Haemochromatosis is a recessive gene which is inherited from parents who either carry one gene mutation (carriers) each or who carry two gene mutations (most likely to be affected with haemochromatosis).  People who have inherited only one gene from either parent are known as carriers and are far less likely to store iron in great quantities than those who carry two genes.  There are currently three genetic mutations that can be tested for by a simple blood test,  C282Y, H63D and S65C.  Possibly in time, more genes will be discovered.

People who have inherited two copies of the same gene such as C282Y/C282Y  or H63D/H63D are known as "homozygous" and those who have inherited one copy of a gene are known as "heterozygous".  About 3% of people who have hereditary haemochromatosis have inherited one copy of C282Y and one copy of H63D  (C282Y/H63D) genes and these people are known as compound heterozygous.   About 90% of people who have hereditary haemochromatosis have the combination of C282Y/C282Y.  When a person has two copies of an of these genes it means that BOTH parents are either be carriers or actually have hereditary haemochromatosis themselves.  It is also interesting that in a few very rare cases, it has been reported that a child has acquired two genes from only one parent ... possibly a spontaneous mutation has occurred  to enable this to happen although further research needs to be done to clarify this).

What Do The Genetic Mutations Mean to Me?

Greater than 90% of haemochromatosis patients are homozygous  for C282Y.  This means they carry a double gene mutation of C282Y.   C282Y/C282Y.  This is the most severe form haemochromatosis and will result in significant iron overload and symptoms will usually appear earlier than with other genetic expressions.

Those who are heterozygous for C282Y are carriers but very rarely develop significant iron overload.  ie, they carry one single mutation of the gene.  C282Y

Compound heterozygotes with one copy of H63D and one copy of C282Y may develop iron overload.  This is usually not as severe as in C282Y homozygotes but may be clinically significant.  C282Y/H63D

Homozygotes for H63D or S65C may have iron overload in some cases, usually mild.  H63D/H63D or S65C/S65C

Heterozygotes of H63D or S65C are very unlikely to have iron overload.  H63D or S65C or H63D/S65C

 

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