The cytogenetic analysis of a child with unspecific dysplastic signs revealed the karyotype: 46, XX, del(11) (q21). Two hypotheses could explain the mild phenotypical expression of this deletion:
1) The material of the deficient part of chromosome 11 is genetically inert or redundant (which seems unlikely);
2) “Gene‐dosis‐compensation” occurs for the loss of genes on the deficient part of chromosome 11.