autosomal recessive disease chromosomal deletion syndrome thrombocytopenia-absent radius syndrome UMLS_CUI:C0175703 ORDO:3320 SNOMEDCT_US_2020_03_01:85589009 ICD10CM:Q87.2 MESH:C536940 DOID:14699 OMIM:274000 disease_ontology NCI:C99038 OMIM mapping confirmed by DO. [LS]. A chromosomal deletion syndrome that is characterized by absence of the radius bone and platelet deficiency and bilateral absence of the radii with the presence of both thumbs and generally transient thrombocytopenia (less than 50 platelets/nL) and that has_material_basis_in compound heterozygosity for a rare null mutation involving the RBM8A gene on chromosome 1q12 on 1 allele and 1 of 2 low-frequency noncoding single-nucleotide polymorphisms in RBM8A on the other. Radial aplasia-thrombocytopenia syndrome Thrombocytopenia with absent radii (TAR) syndrome chromosome 1q21.1 deletion syndrome syndrome