Phelan-McDermid Syndrome Primer

I first heard about Phelan-McDermid Syndrome (also called PMS, but not to be confused with the female monthly cycle issues) after reading this recent blog post on Autism Speaks. PMS is related to autism due to behavioral symptoms (poor eye contact, social anxiety, and perseverative actions) but some question whether the genetic deletion is a cause of autism or if it separates these individuals from other spectrum disorders. Because many of the symptoms overlap, children with PMS may be diagnosed with autism or ADHD or dystonic CP or some combination of these unless a specific genetic test is performed.

PMS is cause by the absence or loss of genes at the tip of Chromosome 22 (a 22q13 deletion). The loss of Shank3/ProSAP2 gene is suspected to be the primary cause of the symptoms associated with PMS. The Shank3 gene plays a role in the formation of the nervous system during fetal development. As in many spectrum disorders, invididuals with PMS may have mild or more severe challenges in several areas, including:

• delayed or absent speech and communication
• low muscle tone (hypotonia) - delayed sitting up, rolling over, crawling, walking
• challenges with eating (sometimes beginning with bottle/breast feeding as a newborn)
• sleep disturbances
• emotional instability

There are also some physical characteristics that may be present:

• may be tall for their age
• subtle facial features: long head shape, puffiness around the eyes, long eyelashes, droopy eyelids, puffy cheeks, large ears
• large fleshy hands, underdeveloped toenails, lack of perspiration - easily overheat.

Both the autism speaks blog above and an article at the Phelan-McDermind Syndrome Foundation website note that as individuals with PMS get older and more skills are expected they fall further behind and their challenges become more apparent. There is also some evidence that individuals with PMS may lose one skill while they make progress in another area.

PMS and Fragile X Syndrome both present strong arguments for the benefits of genetic testing - basically to receive a more specific diagnosis that will allow more focused efforts in intervention, support, and treatment. Some of the comments from the autism speaks blog article seemed to imply that this level of specificity is not necessary if the child is "accepted" and supported in their education and development. What do you think about these issues? We have not pursued any genetic testing for our daughter (yet) mostly due to financial considerations and insurance concerns. Certian phrases in this article made me wonder if we should, though. For instance similar to the little girl highlighted by Autism Speaks, several people have noted that our daughter is "too social" to be autistic, though that is her official diagnosis. I maintain that though she enjoys being with people she does not understand social constructs...her desire to be with people is a great motivator for helping her learn some of the obvious rules of social behavior, but some of the more subtle interactions still seem to be beyond her reach. I am more curious than ever whether we should consider genetic testing and whether it would clear up some of the mysteries we continue to face, but given our excellent progress to date I wonder how much we would gain. I welcome your input...just click on comments below.

If you are interested in learning more about Pheland-McDermid Syndrome I suggest you begin here.