Any relative who is two meioses away from a particular individual in a pedigree; a relative with whom one quarter of an individual's genes is shared (i.e., grandparent, grandchild, uncle, aunt, nephew, niece, half-sibling)

SDR. An individual's relative who is an aunt, uncle, grandparent, grandchild, niece, nephew, or half-sibling.

grandparent, aunt, uncle or grandchild.