ADSLD is considered an autosomal recessive disorder. What the hell does that mean? Let’s figure it out…
'Autosomal' refers to the type of chromosome. Humans have 46 chromosomes, 23 from each parent. 2 of those are sex chromosomes (X and Y). Aside from the sex chromosomes, which are lettered, autosomal chromosomes are numbered. ADSLD occurs on the 22nd chromosome, so it is autosomal.
‘Recessive’ refers to how many copies are necessary to cause disease. In an autosomal recessive disorder like ADSLD, two copies are required (one from each parent) to cause disease. In an autosomal dominant disorder (examples include Ehlers-Danlos syndrome and Huntington disease) only one copy is necessary to cause disease.
What does this have to do with Shakespeare?
In 2004 I was in college studying theater arts. In a Shakespeare scene study class, I was partnered with a swarthy young man named Justin, the Demetrius to my Helena. During a run-through of our scene together, thunder clapped as I knocked him out of his chair, and that was that. A decade later we had Jonah on the way.
Each child born to recessive carriers of a disorder has a 25% chance of being born with the disease. So really, the extraordinary thing isn’t that my kids were born affected, although it would have been a bad bet on 100% of my children having ADSLD. In reality, what is rare is that Justin and I found each other in the first place.
Even more rare, we are homozygous (2 copies of the same R246H variant.)
This is not true of all affected people!
Keep learning about this in Blame it On Shakespeare : Part 2...
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