GENETIC TESTING IS BACK !

Genetic testing came back from America yesterday too. This is different to the enzyme test previously done.

This test was to see if they could find the specific ADA genetic mutation. Sometimes they cannot find it or it has not been reported before . In our case a few other cases have been reported with our same mutation.

Now for those who wish they were doctors and or who understand genetics, I have included below the doctors email re this. From my research into the genetics part of it I have identified four other children ( Worldwide) that carry the exact same genetic coding we have for ADA deficiency. Pretty scary stuff - although I cannot say for sure that these would be the only 4 others,but it just shows how rare this thing is. We knew that anyway given Harrison being only the fourth child diagnosed in Australia with ADA deficiency in the last 10 or 15 years, but this sort of confirms it for me.

The number 4 seems to be a common theme here - Harrison is my 4th Child, he is the 4th diagnosed in Australia with ADA-SCID, and only 4 others I can find in the world with the same genetic mutation, and according to statistics we have a 1 in 4 chance of having a child with ADA deficiency. Very Scary Stuff!!!

I am going to ask for a more detailed breakdown of what this means exactly when we visit the hospital next week - and of course Google myself to death to find answers to my questions that I can then convert the below to normal speak - for translation to you all. :)

Email detail from Doctors: "Harrison (patient) is homozygous for the A329V mutation in exon 11 (c.986C>T); both of his parents and his sister Ella are carriers for this mutation.

A329V has occurred in a number of ADA deficient patients with SCID,. When expressed in E. coli, human ADA cDNA carrying A329V has about 0.05% of ADA activity expressed by the wild type cDNA (Arredondo Vega et al AmJ Hum Genet 63:1049, 1998). "

An Exon is a very small part of a gene. It is the part that holds the particular coding if you like for your genetic makeup. They are numbered and so that is how the genetics Doctors can identify where a particular trait comes from – like this ADA gene. So I think it goes that - in Harrison’s case on chromosome 20 is where the ADA gene lives. The mutation that causes the ADA deficiency appears on Exon 11 within that ADA gene. Because of this mutation, (which both Scott I carry), if a child is born who gets both sets of these mutated genes, then they have the disorder. Harrison is this child. Luckily our only child AFFECTED. Ella carries the disorder ( and so only got 1 set of the mutation and the other set she got is OK) and it looks as if Marlie & Sterling are ok and probably not carriers.

It is known as autosomal recessive genetic disorder. It is a genetic trait we both carry - with no prior family history on either side, so we are just unlucky that Harrison has this - but ... We as a family are very lucky that all kids aren’t affected – as we have a 1 in 4 chance of having a child with ADA deficiency, the way genetics really works means that ALL of the kids could have been affected. We just got lucky. Like we got lucky that Harrison and Ella were a perfect match for Bone Marrow.

I have since found out that 80% of patients who need a bone marrow transplant don't end up getting one from a sibling. So we are truly very lucky indeed.