Thursday, 28 July 2016

Spatax Meeting - Papers, Day 2, part 1

This is the second instalment of the papers presented, this time the morning of the second day. As per day 1, the papers were a mix of HSP and Ataxia papers, and I focused on paying most attention to the HSP papers.

Full post index:
Papers Day 1:
Papers Day 2a:
Papers Day 2b:
Papers Day 3:
Posters 1:
Posters 2:

Day 2 was opened by Peter Bauer Peter talked about genetic sequencing and genetic testing using gene panels (i.e. a sample from a patient is tested against multiple specific genes for a match). He outlined that there are three main areas for problems in getting a genetic test, obtaining the sample, doing the preparation for sequencing, and in the interpretation of the results. The perfect genetic test would know about all possible variants and test for repeat expansions. There are guidelines for diagnostic testing: Asking predictive questions of tests can be tough when there is only limited data available - results can be ambiguous. There can be diagnostic gaps in the data - which would miss patients out who would otherwise get a diagnosis. Another issue is that such a test can show "incidental" findings - i.e. a gene is matched which was not part of the original search remit - consent is needed from the patient to find an report these findings. Peter indicated that 5-10% of rare disease patients have two different conditions. He also indicated that it would be a good idea for the Spatax network to work with the UK 100,000 genome project

There were a couple of people - Tzoulis Charalampos and Robert Roxburgh who talked about higher incidences of varying conditions in certain areas - Western Norway and Maori / Pacific Islands respectively - due to population bottlenecks in the past, also known as founder effects. Robert was talking about Canvas Syndrome - a type of Ataxia - noting that a chronic cough can be a symptom.

Rebecca Schule gave a really good overview of HSP. She indicated that the recessive HSP's have an age of onset around 1 decade earlier than the dominant types, and that there is some influence on the age of onset with the mutation type for certain HSP's. When looking at the severity of HSP, this is partially explained by the disease duration, but that only accounts for 10% of the range of severity. They have looked at how the Spastic Paraplegia Rating Scale varies with type of HSP in order to look at rate of change. They found that SPG4 progresses relatively slowly, with a change of 0.38 points per year, whereas SPG5 is faster at 0.74 points per year. You can find details here:  However, she noted that there are a load of factors which affect patients which are not assessed in the SPRS. For example, with a family there may be differences with the same mutation - perhaps a 30 year difference in the age of onset. One of the key questions is deciding when the disease starts. Another important factor is that day-to-day changes in mobility and other symptoms can be greater than the progression of the disease over a few years. There are lots of unknowns. New tools include biomarkers, gait paradigms and video gait analysis. SPG4 is a good candidate for looking at the effects of genetics and environment to understand more about the variation.

As last time, I realise that it is on a very different level to my normal posts. I know I've just used a lot of terms that I dont normally use, and I've just kept this post to the points which I perceived to be most important.

Key takeaway points are:

  • Genetic test results can be ambiguous.
  • Changes in health can be indicators of underlying problems - e.g. the chronic cough
  • Day-to-day variation can be bigger than year-to-year progression

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