16q24

16q24 is a cytogenetic location on the long arm of chromosome 16, corresponding to region 24 (q24). In clinical genetics, 16q24 is used to describe chromosomal deletions or duplications that include this region, as well as the specific gene content within it. The exact base-pair coordinates depend on the reference genome build, so the physical extent of the region can vary between analyses.

The most well-characterized gene in 16q24 is ANKRD11, located at 16q24.3. Haploinsufficiency of ANKRD11 causes KBG syndrome, a developmental disorder marked by intellectual disability or learning difficulties, distinctive facial features, skeletal anomalies, and often macrodontia of the permanent maxillary central incisors.

Structural rearrangements involving 16q24 have clear clinical relevance. Deletions that encompass ANKRD11 and adjoining regions can result in KBG syndrome, while duplications in 16q24 or nearby intervals can produce a range of phenotypes, typically with variable expressivity and including developmental delay and dysmorphic features.

Diagnosis and interpretation rely on genomic testing. Chromosomal microarray analysis is commonly used to detect copy-number changes in 16q24, with karyotyping, fluorescence in situ hybridization (FISH), or sequencing employed to refine breakpoints. Clinical interpretation depends on the size and gene content of the rearrangement; pathogenic deletions of 16q24.3 involving ANKRD11 are typically reported as KBG syndrome, whereas duplications require careful assessment of their gene content and associated features.

See also: KBG syndrome, chromosome 16 disorders, copy-number variation, ANKRD11.

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