Researchers at Boston Children's Hospital have developed a custom-made drug for a six-year-old girl, Mila Makovec. The child suffers from a form of Batten disease, which has limited mobility and reduced vision. Mila's symptoms were caused by a mutation in the CLN7 gene.
Unlike the usual, the mutation affected only one of the two alleles; the other was affected by an unknown mutation. To treat this form of the disease, doctors had to find this other mutation and understand the mechanism. For this purpose, they performed a total DNA sequencing. This allowed them to identify an anomaly of the mRNA, which modified the way the gene is expressed.
To resolve both abnormalities, doctors developed new forms of antisense oligonucleotide or ASO. The new drugs had the same skeleton as that used for spinal muscular atrophy.
The scientists tested them in vitro on the patient's cells, choosing the one that worked best. At this point they also tested it on guinea pigs and, once the safety of the drug was proven, they used it on Mila. Before the test, Mila had 15-30 seizures per day, each lasting an average of 1-2 minutes. With therapy, the frequency dropped to 0-20 attacks per day lasting less than a minute.