12q13112q15

12q13112q15 is a chromosomal rearrangement notation referring to the long arm of chromosome 12, spanning the region from band q13.1 to q15. In cytogenetic reports this interval may be affected by an interstitial duplication, triplication, or another unbalanced rearrangement that alters copy number for the genes within 12q13.1–q15. The exact cytogenetic description, including whether the event is a gain or complex rearrangement, determines the resulting genetic imbalance.

Clinical features associated with alterations in this interval are highly variable and depend on the size of the affected region and the genes it contains. Reported individuals with 12q13.1–q15 alterations have shown developmental delay or intellectual disability, hypotonia, speech and motor delays, and congenital anomalies in some cases, while others may have milder effects or appear clinically normal, influenced by mosaicism and background genetic factors. Phenotypes are not uniform, and genotype–phenotype correlations remain incompletely understood.

Detection and interpretation rely on genetic testing technologies. Conventional karyotyping can identify large unbalanced rearrangements; higher-resolution methods such as fluorescence in situ hybridization (FISH), array-based comparative genomic hybridization (array CGH), or SNP arrays can define breakpoints and copy-number status more precisely. Parental testing helps determine whether the alteration is de novo or inherited, which informs recurrence risk.

Inheritance and management considerations: most cases are de novo, but familial rearrangements can occur, necessitating genetic counseling. Management is individualized and typically multidisciplinary, addressing developmental, medical, and educational needs, with monitoring for associated anomalies as indicated by the specific genes involved in the 12q13.1–q15 region.