In addition, the frequency of positive anti-TPO antibodies increased with age from 1% at the age of 12 months, to 6% at age 24 months and 25% at age 10.7 years in the DS placebo group, whereas there was a trend toward a lower percentage of children developing anti-TPO positivity among DS patients who received thyroxine treatment. Here, TPO is linked to Dravet syndrome.