Intragenic KANSL1 mutations and chromosome 17q21.31 deletions: broadening the clinical spectrum and genotype-phenotype correlations in a large cohort of patients

The 17q21.31 deletion syndrome phenotype can be caused by either chromosome deletions or point mutations in the KANSL1 gene. To date, about 60 subjects with chromosome deletion and 4 subjects with point mutation in KANSL1 have been reported. Prevalence of chromosome deletions compared with point mutations, genotype-phenotype correlations and phenotypic variability have yet to be fully clarified.