I am reading a journal paper about the association between NCAM2 and autism, and I have come across the following:

We performed microarray analysis and identified a 1.6-Mb deletion of 21q21.1-q21.2, containing the NCAM2 gene but no other functional gene.

I am not sure what the '-q21.2' after '21q21.1' in '21q21.1-q21.2' means. Does it mean that the deletion goes between band 21.1 to 21.2 on the long arm of chromosome 21 (21q)? Any insights are appreciated.


1 Answer 1


Cytogenetic map notation uses the following form:


Where A is the chromosome number, p is the petit / short arm, q is the queue / long arm, B is the band, C is the sub-band, and D is the sub-sub-band.

So, 21q21.1-q21.2 designates a region on the long arm of chromosome 21, band 2, sub-band 1, between sub-sub-bands 1 and 2.

Source: NCBI Genetics Review (archived version)


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