So you’ve never heard of Sotos before? I hadn’t either, until the first round of genetic testing (the one that found the duplication on our son’s 5th chromosome) indicated that further evaluation to assess for a possible diagnosis of Sotos was recommended. We remain grateful to this day for his geneticist’s office who fought diligently to get both rounds of testing covered by our insurance, who wanted to deny payment, because both rounds of testing were crazy expensive. The first round was just short of $8000, the gene mapping was I think even more then that. Can you imagine how many people may go without diagnosis for genetic disorders for want of insurance or the money to pay the costs?
Sotos Syndrome is a genetic disorder that is caused by a mutation to or other problem with the NSD1 gene, which is found on the 5th chromosome, and is estimated to effect roughly 1 in 14000 live births. For our son, it is believed that the break point of his duplication caused the disruption to his NSD1 gene. The vast majority of individuals with Sotos did not inherit the condition, but it developed as a result of spontaneous genetic changes in the womb. However, someone with Sotos has a 50% chance of passing this condition on to each of their children.
Individuals with Sotos usually have advanced bone age (our son does), a larger noggin (Sotos is also known as Cerebral Gigantism), and above average growth during childhood. Sotos can cause a wide array of secondary conditions and often comes with intellectual disability, ranging from mild to severe depending on the person. Common secondary conditions include ADHD, Autism, Seizures, Cardiac problems, Scoliosis, degenerative eye disorders, kidney/urinary problems, and increased risks for certain cancers. Frequently there is delayed expressive language, lower muscle tone especially in the core, and difficulty with motor planning and other developmental delays.
Sotos can be diagnosed by comparing cranial and height measurements to typical size and development patterns, checking bone age, and assessing for certain stereotypical facial features. It can also be diagnosed and/or confirmed via genetic testing and gene mapping, as it was for our son.
You can find a brief overview of Sotos on the National Library of Medicine, found here:
https://ghr.nlm.nih.gov/condition/sotos-syndrome
I also really like this sheet from the New England Genetics Collaborative, which was prepared to help providers in the school setting. It has a lot of excellent information on many aspects of Sotos, including common secondary medical conditions, incidence of intellectual disability, and areas of learning that typically require additional support for individuals with this syndrome.
*I have referenced both of these sources for this FAQ page, as well as conversations with our son’s totally awesome geneticist.