Gestational treatment to prevent recurrent lethal neonatal hemochromatosis
Neonatal hemochromatosis (NH) is characterized as a
condition in which fetuses and infants under one month of age have accumulation
of iron in the liver and other tissues in a pattern similar to that seen in
hereditary hemochromatosis. Most cases result in stillbirths, and the average
life expectancy of children born with this disease is less than a few days.
Death results mainly from liver failure. However, some affected babies have been
successfully treated by medical means (with survival reported to be less than
20%) and by liver transplantation (survival reported to be less
than 50%).
It has become very clear that NH
causes damage to the fetal liver, which usually starts at 20-24 weeks of
pregnancy. Considering all known causes of fetal disease, NH has been thought to
possibly be the result of a genetic disease (gene defect). However, some curious findings in NH are
hard to explain in this way. A
mother may have one or more unaffected children before having the first affected
child. Thereafter, the following
pregnancies may end in either a late stillbirth or a child born with NH. Also, mothers have given birth to
affected children with different fathers. The point is: there is no concrete
evidence that NH is inherited through genes.
Treatment
We have developed a theory
concerning the cause of NH upon which we have based the treatment of prospective
mothers who have had children with NH. We believe that the cause of recurrent NH
involves certain women developing an abnormal immune response to their unborn
babies (called alloimmunity).
According to this theory, the mother's immune system mounts an attack
against a fetal liver protein and results in liver damage and a direct or
indirect effect on fetal iron storage.
Several years ago we began to treat
pregnant women on a research protocol.
The purpose of treatment is to limit the elaboration of immunoglobulin
(mother's immune attack) directed against the fetus (baby). The results of treatments performed as
of August 2005 are: 26 women have been treated though 29 pregnancies, all of
which ended in a live and reasonably healthy baby. About 75% of the babies showed some
evidence of being affected, but only about 15% had significant liver
disease. All 29 babies survived
with medical care alone (no liver transplant). This is significantly different
from these same women's prior affected pregnancies when treatment was not given
in which there was only about 10% survival with medical therapy.
Long-term outlook
The results suggest that the course
of the pregnancies was altered by the treatment to permit the birth of children
with much milder NH and no pregnancy or newborn deaths. These findings suggest
that a simple therapy might prevent this devastating disease. Further study is underway to confirm
these results.
Further reading:
Recent report of treatment successes
Neonatal hemochromatosis overview
Argument for immune basis of NH