Pallister Hall syndrome (PHS)

Abstract

Major findings: Hypothalamic hamartoma: a nonenhancing mass in the floor of the third ventricle posterior to the optic chiasm that is isointense to grey matter on T1 and T2 pulse sequences of an MRI, but may have distinct intensity on FLAIR. (Neither cranial CT examination nor cranial ultrasound examination is adequate for diagnosis of hypothalamic hamartoma). Central polydactyly: The presence of six or more well-formed digits with a ‘Y’ shaped metacarpal or metatarsal bone. Postaxial polydactyly: Can be either PAP-A with a well shaped digit on the ulnar or fibular aspect of the limb, or PAP-B with a rudimentary digit or nubin in the same position. Bifid epiglottis: A midline anterior-posterior cleft of the epiglottis that involves at least two-thirds of the epiglottic leaf. It is a useful feature for clinical diagnosis because it appears to be very rare in syndromes other than PHS and is also rare as an isolated malformation. Other: Imperforate anus, renal abnormalities including cystic malformations, renal hypoplasia, ectopic ureteral implantation, and pulmonary segmentation anomalies such as bilateral bilobed lungs.