A microdeletion at 22q13.3 results in the Phelan-McDermid Syndrome.


General clinical features:

(1) neonatal hypotonia

(2) normal to accelerated height for age (may appear tall and thin)

(3) failure to thrive due to poor oral intake

(4) severely delayed to absent speech

(5) global developmental delay

(6) autistic like affect


Dysmorphic facial features:

(1) dolichocephaly ("long headed")

(2) full brow

(3) flat midface

(4) ptosis

(5) puffy eyelids

(6) long eyelashes

(7) wide nasal bridge

(8) puffy cheeks

(9) pointed chin

(10) large, prominent ears

(11) deep set eyes

(12) bulbous nose

(13) strabismus

(14) widely spaced teeth and/or malocclusion

(15) epicanthal folds

(16) long philtrum

(17) high arched palate


Hands and feet:

(1) large and fleshy hands with normal fingernails

(2) fifth finger clinodactyly

(3) dysplastic toenails

(4) 2-3 toe syndactyly

(5) puffy, swollen feet


Other findings:

(1) mouthing or chewing non-food objects

(2) tooth grinding

(3) sacral dimple

(4) decreased perspiration with tendency to overheat

(5) increased tolerance to pain


An infant with these findings should be tested for the microdeletion with FISH analysis.


To read more or access our algorithms and calculators, please log in or register.