With autism statistics at 1 in 68 children, the search for information on the causes and possible treatments is a priority for many neuroscientists. While there is no known cause of autism, it occurs in approximately 60% of children who have Fragile X syndrome so researchers are looking at ways the two disorders are connected. Fragile X is a genetic disorder that causes certain facial features like a large forehead and ears as well as intellectual disabilities, social anxiety and self-stimulating behavior like hand flapping. It occurs as a result of the expansion of the CGG trinucleotide repeat affecting the Fragile X mental retardation 1 (FMR1) gene on the X chromosome, resulting in a failure to express the fragile X mental retardation protein (FMRP), which is required for normal neural development.
There are no treatments available for Fragile X itself, nor are there medications for most autism spectrum disorders however some children who have ADHD or anxiety along with these conditions do take medications for focus and/or stress relief. New research into how it relates to autism might offer another avenue for treatment however.
A study by researchers with the UC Davis MIND Institute has found that treatment with the anti-depressant drug sertraline (brand name Zoloft) may provide small but important improvements in intellectual ability and social participation in children with fragile X syndrome, but only at very young ages. The study is published online in the Journal of Developmental & Behavioral Pediatrics and is the first clinical trial to look at low doses of Zoloft for the learning and emotional issues children with the genetic disorder suffer from. The researchers noted that language acquisition also improved in the children who took Zoloft.
In a press release from UC Davis Randi Hagerman, senior author and medical director of the UC Davis MIND Institute stated, “These are important outcomes that warrant further studies of sertraline in fragile X syndrome and in autism spectrum disorder. All of the families that completed the study wanted to continue their children on sertraline.”
Since Zoloft is a selective serotonin reuptake inhibitor (SSRI) and serotonin levels are low during early development, when synapse formation is most rapid there is a window in the first five years of a child’s life where boosting serotonin levels could improve development. This very crucial period of time in a child’s life could be the best time for treatments that involve SSRIs. Previous research in mouse models also showed that SSRIs stimulate a substance in the brain called brain-derived neurotrophic factor (BDNF) which is necessary for proper synaptic growth. Hagerman believes there could be a link between SSRIs and this development in children with Fragile X.
“Given the lack of maturation of synapses in fragile X syndrome, along with BDNF’s role in synaptic maturation, plasticity and neurogenesis, SSRIs are of particular interest for the treatment of fragile X syndrome,” Hagerman said.
The research involved 52 children between the ages of 2 and 5 who were monitored for cognitive development and social skills for a period of 3.5 years. Half of the children were given Zoloft and half a placebo. The children who received the medication showed better progress in areas of cognition and social functioning as well as language development. In the video below Dr. Hagerman explains more about the study and what it might mean for children affected by Fragile X.
Sources: UC Davis
, Journal of Developmental Behavioral Pediatrics
, National Fragile X Foundation