Categories: Limbs / fins / digit / tail phene

Mendelian trait/disorder: yes

Mode of inheritance: Probably autosomal recessive

Disease-related: yes

Key variant known: no

Cross-species summary: Also known as radial agenesis and radial aplasia/hypoplasia

Molecular basis: Bilgen et al. (2023) "Clinical and genetic analyses were conducted on a Siamese cat family (n = 18), including two siblings with RH [radial hemimelia]. ... Whole genome sequencing was completed on the two cases and the parents. Genomic data were compared with the 99 Lives Cat Genome data set of 420 additional domestic cats with whole genome and whole exome sequencing data. Variants were considered as homozygous in the two cases of the siblings with RH and heterozygous in the parents. ... Twenty-two DNA variants were unique and homozygous in the affected kittens and heterozygous in the parents. Seven variants clustered in one chromosomal region, including two frameshift variants in cardiomyopathy associated 5 (CMYA5) and five variants in junction mediating and regulatory protein, P53 cofactor (JMY ), including a missense and an in-frame deletion. ... One deletion and several base substitutions in CMYA5 and JMY are proposed as tentative candidate variants for the phenotype, implicating their role in bone development. These genes should be investigated in other cats with RH and evaluated in a larger population to determine allele frequencies in various breeds and populations."

Clinical features: Bilgen et al. (2023): "Radiographs of the female [Siamese] kitten revealed bilateral absence of the radii and bowing of the humeri, while the male kitten showed a dysplastic right radius. Echocardiography suggested the female kitten had restrictive cardiomyopathy with a positive left atrial-to-aortic root ratio (LA:Ao = 1.83 cm), whereas hypertrophic cardiomyopathy was more likely in the sire, showing diastolic dysfunction using tissue Doppler imaging (59.06 cm/s)."

Breed: Siamese (Cat) (VBO_0100221).
Breeds in which the phene has been documented. (If a likely causal variant has been documented for the phene, see the variant table breeds in which the variant has been reported).