Variants in ROR2 gene are spread all over the gene and most of them causing AR Robinow syndrome are missense variants. The heterozygous parents are usually normal and do not show digit anomalies.
The causative variants associated with Brachydactyly type B1 are non-sense or frameshift and are clustered around codons 441 to 467 and 749 to 760 and are always in heterozygous state. This suggests some genotype-phenotype correlation. One family with homozygotes for frameshift variant has been described and those cases had severe transverse limb reduction defects. In one family the homozygous individual with truncating variant had severe autopod deficiency and the carriers had brachydactyly B1.
A few cases with heterozygous variants are described to have renal disease, immunodeficiency, and dysmorphic dysplasia.