1q21.1 copy number variations

1q21.1 copy number variations (CNVs) are rare aberrations of human chromosome 1.

In a common situation a human cell has one pair of identical chromosomes on chromosome 1. With the 1q21.1 CNVs one chromosome of the pair is not complete because a part of the sequence of the chromosome is missing, or overcomplete, because some parts of the sequence are duplicated. The result is that one chromosome is of normal length and the other one is too long or too short.