Perlman syndrome (PRLMNS) is an autosomal recessive congenital overgrowth syndrome with similarities to Beckwith-Wiedemann syndrome (BWS; 130650). Affected children are large at birth, are hypotonic, and show organomegaly, characteristic facial dysmorphisms (inverted V-shaped upper lip, prominent forehead, deep-set eyes, broad and flat nasal bridge, and low-set ears), renal anomalies (nephromegaly and hydronephrosis), frequent neurodevelopmental delay, and high neonatal mortality. Perlman syndrome is associated with a high risk of Wilms tumor, with a 64% incidence in infants surviving beyond the neonatal period. The tumor is diagnosed at an earlier age in these individuals compared with sporadic cases (less than 2 years and 3-4 years of age, respectively), and there is a high frequency of bilateral tumors (55%). Histologic examination of the kidneys in children with Perlman syndrome shows frequent nephroblastomatosis, which is a precursor lesion for Wilms tumor (summary by Astuti et al., 2012).

Diaphanospondylodysostosis is a rare, recessively inherited, perinatal lethal skeletal disorder. The primary skeletal characteristics include small chest, abnormal vertebral segmentation, and posterior rib gaps containing incompletely differentiated mesenchymal tissue. Consistent craniofacial features include ocular hypertelorism, epicanthal folds, depressed nasal bridge with short nose, and low-set ears. The most commonly described extraskeletal finding is nephroblastomatosis with cystic kidneys, but other visceral findings have been described in some cases (summary by Funari et al., 2010).