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Head shape concerns are one of the most common issues a pediatric clinician will encounter in an infant visit. Although most of these concerns have a benign cause, there are a few head shapes that suggest premature cranial suture fusion (craniosynostosis) and require surgical treatment. On the other hand, nonsynostotic head shape problems are a much more common benign entity caused by external mechanical forces that mold the pediatric skull and are associated with normal patent sutures.1 This is often referred to as deformational or positional plagiocephaly (PP) because the altered head shape is due to the positioning of the head with respect to its surroundings in-utero, at birth, or postnatally.2 Plagiocephaly simply refers to an asymmetry of the head. Treatment of PP is nonsurgical. Thus, accurate differentiation between these entities is essential, with pediatric clinicians as the first line.
After the American Academy of Pediatrics' “Back to Sleep” Campaign, which began in 1992, the prevalence of PP significantly rose from approximately 5% to between 21% and 46% at age 7 months.3 Initially, a large number of these patients were incorrectly diagnosed as having craniosynostosis, until a multidisciplinary group clearly delineated the differences in etiology and clinical presentation between positional deformities and true synostosis.4 In a prospective cohort study of 440 infants between age 2 and 3 months in 2010, the incidence of PP was 46.6%, with 78.3% having a mild form.5 Cumulative exposure to supine position is the best predictor of PP. Other risk factors include assisted delivery, first-born child, male sex, intrauterine constraint, and infant neck problems (ie, torticollis).6
On the other hand, craniosynostosis affects 1 in 2,000 to 1 in 5,000 infants. Any of the sutures of the skull can be prematurely fused, resulting in different head shapes.1 Causes of craniosynostosis are less well understood compared with PP. A minority of craniosynostosis cases are related to craniofacial syndromes, such as Apert, Crouzon, Pfeiffer, Saethre-Chotzen, or Muenke syndromes. In most of these syndromes, mutations in the fibroblast growth factor receptor pathway, transcription factors that specify and maintain cell identity, and proteins important for development of the frontonasal neural crest have been implicated. Although the genetic mutations that lead to the development of syndromic craniosynostosis have...