Association of 17q24.2-q24.3 deletions with recognizable phenotype and short telomeres

摘要

Microdeletions of 17q24.2-q24.3 have been described in several patients with developmental and speech delay, growth retardation, and other features. The relatively large size and limited overlap of the deletions complicate the genotype-phenotype correlation. We identified a girl with intellectual disability, growth retardation, dysmorphic features, and a de novo 2.8 Mb long deletion of 17q24.2-q24.3. Her phenotype was strikingly similar to one previously described boy with Dubowitz syndrome (MIM 223370) and a de novo 3.9 Mb long deletion encompassing the deletion of our patient. In addition, both patients had the shortest telomeres among normal age-matched controls. Our review of all 17q24.2-q24.3 deletion patients revealed additional remarkable phenotypic features shared by the patients, some of which have consequences for their management. Proposed novel genotype-phenotype correlations based on new literature information on the region include the role of PSMD12 and BPTF, the genes recently associated with syndromic neurodevelopmental disorders, and a possible role of the complex topologically associated domain structure of the region, which may explain some of the phenotypic discrepancies observed between patients with similar but not identical deletions. Nevertheless, although different diagnoses including the Dubowitz, Nijmegen breakage (MIM 251260), Silver-Russell (MIM 180860), or Myhre (MIM 139210) syndromes were originally considered in the 17q24.2q24.3 deletion patients, they clearly belong to one diagnostic entity defined by their deletions and characterized especially by developmental delay, specific facial dysmorphism, abnormalities of extremities and other phenotypes, and possibly also short telomere length.