Chromosome 1q21.1 Deletion Syndrome, 1.35-Mb, also known as chromosome 1q21.1 deletion syndrome, is related to thrombocytopenia-absent radius syndrome and chromosome 1q21.1 duplication syndrome. An important gene associated with Chromosome 1q21.1 Deletion Syndrome, 1.35-Mb is DEL1Q21 (Chromosome 1q21.1 Deletion Syndrome), and among its related pathways/superpathways is 1q21.1 copy number variation syndrome. Affiliated tissues include eye and heart, and related phenotypes are intellectual disability and frontal bossing