Inheritance: autosomal dominant with variable penetrance
Chromosome affected: 4p16.3
Gene affected: fibroblast growth factor receptor 3 (FGFR3), with a specific mutation (Pro 250 Arg).
Key clinical findings:
(1) unilateral or bilateral coronal craniosynostosis
(2) fusion of carpal and/or tarsal bones (at the wrist and ankle, respectively)
Additional findings:
(1) macrocephaly
(2) normal intellect to mild intellectual delay
(3) hearing loss
(4) short fingers and toes (brachydactyly
(5) broad first toe (hallux)
(6) cervical spine anomalies
(7) thimble-like middle phalanges
(8) mild maxillary hypoplasia
(9) palpebral fissures that show lateral downward slanting
(10) ocular hypertelorism
(11) cone-shaped epiphyses
(12) fifth finger clinodactyly
