Phenotypic and mutational spectrum of <i>ROR2</i> ‐related Robinow syndrome
Ariadne Ramalho de Lima, Bárbara Merfort Ferreira, Chaofan Zhang, Angad Jolly, Haowei Du, Janson J. White, Moez Dawood, Tulio Cesar de Lima Lins, Marcela A. Chiabai, Ellen van Beusekom, Mara S. Córdoba, Érica Carine Campos Caldas Rosa, Hülya Kayserili, Virginia Kimonis, Erica Wu, Cecília Mellado, Vineet Aggarwal, Antônio Richieri‐Costa, Décio Brunoni, Talyta M. Canó, Alexander A.L. Jorge, Chong Ae Kim, Rachel Sayuri Honjo, Débora Romeo Bertola, Raissa M. Dandalo‐Girardi, Yavuz Bayram, Alper Gezdirici, Elif Yılmaz Güleç, Evren Gümüş, Gülay Can Yılmaz, Nobuhiko Okamoto, Hirofumi Ohashi, Zeynep Coban‐Akdemir, Tadahiro Mitani, Shalini N. Jhangiani, Donna M. Muzny, Neysa A.P. Regattieri, Robert Pogue, Rinaldo Wellerson Pereira, Paulo Alberto Otto, Richard A. Gibbs, Bassam R. Ali, Hans van Bokhoven, Han G. Brunner, V. Reid Sutton, James R. Lupski, Angela Maria Vianna‐Morgante, Claudia M.B. Carvalho, Juliana F. Mazzeu
Abstract
Robinow syndrome is characterized by a triad of craniofacial dysmorphisms, disproportionate-limb short stature, and genital hypoplasia. A significant degree of phenotypic variability seems to correlate with different genes/loci. Disturbances of the noncanonical WNT-pathway have been identified as the main cause of the syndrome. Biallelic variants in ROR2 cause an autosomal recessive form of the syndrome with distinctive skeletal findings. Twenty-two patients with a clinical diagnosis of autosomal recessive Robinow syndrome were screened for variants in ROR2 using multiple molecular approaches. We identified 25 putatively pathogenic ROR2 variants, 16 novel, including single nucleotide variants and exonic deletions. Detailed phenotypic analyses revealed that all subjects presented with a prominent forehead, hypertelorism, short nose, abnormality of the nasal tip, brachydactyly, mesomelic limb shortening, short stature, and genital hypoplasia in male patients. A total of 19 clinical features were present in more than 75% of the subjects, thus pointing to an overall uniformity of the phenotype. Disease-causing variants in ROR2, contribute to a clinically recognizable autosomal recessive trait phenotype with multiple skeletal defects. A comprehensive quantitative clinical evaluation of this cohort delineated the phenotypic spectrum of ROR2-related Robinow syndrome. The identification of exonic deletion variant alleles further supports the contention of a loss-of-function mechanism in the etiology of the syndrome.