Striped Socks

Sarah continued her recovery at home and was making good progress. In fact life was pretty much back to normal. Within weeks she was no longer on medication and was again putting on weight. There was however one thing playing on my mind. When Sarah was first admitted to Guy's we had been told the hospital wanted to do a test to check for any genetic conditions. I knew that a sample had been taken but did not recall ever seeing the results.  I told myself, without conviction, that as we had not heard anything from the hospital the result must have been negative.  In January 2006, three months after Sarah's surgery, we had our first check up at the local cardiac clinic and received the good news that Dr. Bell, Cardiology Consultant, was please with her progress. I took the opportunity to ask about the result of the test and was told they could not find the results on file but would check. The following day we received the call I had half expected. The test had revealed a genetic abnormality and an appointment would be arranged with the genetics team at Guy's.

As I sat in the waiting room for the Genetics Clinic at Guy's Hospital I noticed that there were 23 photographs on the wall and that each photograph was of a pairs of striped socks of varying sizes and colours. At first glance this looked like a strange piece of artwork for a waiting room but when reading the accompanying explanation its all made sense.

The 23 photographs represent the 23 pairs of chromosomes in a normal human cell.  At conception we get one set of 23 chromosomes from our mother and one set of 23 chromosomes from our father. We have 22 pairs of Chromosomes numbered 1 through 22 and two sex chromosomes.  We always receive an X sex chromosome from our mother with either and X or a Y sex chromosome from our father.  X from Mum and X from Dad and the result is a baby girl. X from Mum and Y from Dad and the result is a boy.  Sometimes a baby acquires an extra chromosome ending up with 47 instead of 46. the most common example of this is Down's Syndrome where a person has an extra copy of Chromosome 21.

When viewed under a microscope a chromosome looks like it has a number of horizontally striped bands hence the stripes on the socks.

The geneticist told us that Sarah has 22q11.2 is deletion syndrome which means that she has a small piece of genetic material missing on one copy of Chromosome 22. The deletion occurs on the long arm of the Chromosome (q) at band 11.2.  The amount of genetic material missing is typically around 40 genes.  Although every one with 22q11.2 DS has the same part of Chromosome 22 missing no two cases are the same.  A full set of chromosomes can be viewed as a blueprint for the body creating how the foetus develops and how we develop and grow after birth.  If part of the blueprint is missing then a number of errors are likely to occur.  Around 180 anomalies are caused by this deletion and a list of this can be found at http://www.22crew.org/professionals/velo-cardio-facial-syndrome-specialist-fact-sheet .

Typically a person with 22q will experience around 30 of these anomalies throughout their life. In my mind this condition is a bit of an "unlucky dip". Nature take out a handful of genes and depending on the genes removed the level of symptoms can be mild or severe.

The frequency of 22q is believed to be around 1 in 1800 live births. This compares with an incidence of 1 in 1,000 for Down's syndrome which is the most common genetic disorder.

The22 Crew www.22crew.org a charity and support group of which I am a trustee is currently hoping to fund a project to confirm the incidence of this condition.

www.22crew.org