Arguably the nastiest inherited illness. Symptoms include involuntary jerking, difficulty swallowing and speaking, lapses of memory, lack of concentration, depression, anxiety, mood swings, irritability and personality changes. Eventually, the patient dies.
Huntington's is caused by a genetic stutter: three letters of the genetic code, C, A and G, are repeated over and over in the DNA encoding a protein called huntingtin. Unlike most genetic disorders, for which a faulty gene must be inherited from both parents, Huntington's requires only one parent to carry the mutation for it to be passed on.
Everyone has some CAG repeats in their huntingtin genes. If the number exceeds 36, the repeat-chain may lengthen over the course of life until the resulting protein becomes toxic. If the number is 40 or more, this will definitely occur. Symptoms usually appear in middle age, as the toxic protein accumulates in and destroys brain cells, particularly in a deeply buried structure called the striatum (specifically the caudate nucleus and putamen).
An estimated 100,000 people in America alone carry the overlong repeat segments in their huntingtin genes, of whom 40,000 already have symptoms.
In September 2025 uniQure, a firm in Amsterdam, announced results from a three-year trial of AMT-130, a microRNA molecule delivered to the brain via a genetically modified but harmless virus using MRI-guided, convection-enhanced stereotactic delivery. AMT-130 binds to the messenger RNA that carries instructions for making huntingtin, causing the cell to destroy the resulting double-stranded RNA before the toxic protein can be produced. The trial of 29 people in America and Europe reported a 75% slowing of disease progression by one widely used measure and a 60% slowing by another, with few worrying side-effects. There is no claim of a cure.
Half Moon tonight. (At least it's better than no Moon at all.)