A blog about the grief after losing a child to Niemann Pick, Type C, a rare disease, and how I'm moving forward with my life.

Wednesday, October 10, 2012

Can I catch NPD?

October is Niemann-Pick Disease Awareness Month.

Niemann-Pick Disease is not like the flu.  You can't catch it by being near someone affected.  NPD is a genetic mutation that is determined at conception.

Here is a refresher from biology class.

All types of NPD are inherited in an autosomal recessive pattern and can affect both males and females. The disease occurs when both copies of a person's gene have a mutation (a change in a gene which causes it to function incorrectly). Carriers have one normally functioning copy of the gene and one copy that does not function correctly due to a mutation; carriers do NOT have NPD. Being a carrier of NPD is not known to lead to any health problems. Less than 1% of people are carriers of any of the NPD genes.

A person with NPD inherits one gene mutation from each parent, both of whom are carriers. Each child of two carrier parents has: a 25% chance of being unaffected and not a carrier (having two working copies of the gene), a 50% chance of being an NPD carrier (having one functional copy and one non-functional copy, like his/her parents), and a 25% chance of having NPD (having no working copies of the gene).


Blood relatives (siblings, aunts/uncles, cousins, etc.) of patients with NPD may also be carriers of an NPD gene mutation.  If the mutations in the affected family member are known, definitive carrier testing can be done for these relatives.  

The different details of each family history will cause the risk figures and other genetic counseling issues to vary from family to family, and in members of the extended family.  Genetic counseling is recommended for all couples in which both partners are known to be carriers or if one partner is a known carrier and the other's status is uncertain.


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