A Scientist Finds Her Child’s Rare Brain Illness Stems from the Gene She Studies

Bad luck is bad luck--not everything has a controllable cause. 70% of all zygotes spontaneously abort.

The difference is that we would leave such children to die a century ago.

I don't know what the modern answer is for children with these kinds of debilitating errors in their DNA.

DNA is pretty interesting. It's kind of like reading a binary file in that every three base pairs constitutes a "codon" or the code for an amino acid, a building block of a protein. In this case, a base pair was knocked out via one of many unfortunate methods, and this causes a "frameshift error".

This is kind of like if you have an array of xyz vertices (common in 3d graphics) xyzxyzxyz and then you suddenly delete one: xzxyzxyz. If you try to read that file, you'll get unintelligible artifacts. Unfortunately, that's what happened to the little girl's gene. Depending on where the error occurs, more or less of the gene is read incorrectly. Sometimes if you're lucky, it occurs near the end and it might not be a big deal, but if it happens at the beginning or middle, the entire protein is messed up.

Anyways, I hope that helps illuminate what's happening here if you weren't already aware.

I'm not a professional biologist, but I sometimes act like one. Please correct me if I got a detail wrong. :)

EDIT: I should mention the reason why those changes don't hurt most people is that there's a lot of non-coding DNA that serves various functions such as structural, can promote the activation of other genes, could be part of disabled viral genomes, and then there's the fact that DNA is a degenerate code (some codons code for the same amino acid). There are probably many other categories that I didn't mention too.

I want to provide some background, which is not typical, but pretty representative. In my 5~6 years as a biologists, I got my hands dirty extensively on 8~10 genes. It means I manipulated the genes in different ways via gene tools to try to figure out their properties. I knew every regions of these genes, even many single nucleotides, and what would happen if mutations occur at these nucleotides/regions. Other than that, I knew 50~60 genes very well. To this day, I can still remember most things about the genes. It is very sad that the random mutation happened to the lovely girl. If we only talk about statistics, the probability of the coincidence may be higher than we first thought.