HLAB 27 Inheriting

If a child has the HLAB27 maker and one parent has been tested and shown not to have it, must the other parent have it or can it skip a generation and actually have been inherited from a grandparent?


This discussion is related to HLA-B27.

[Margreth]

If a child has the HLA-B27 marker and one parent has been shown not to have it then yes, the other parent must be positive for it. It should be noted however that most people that are HLA-B27 positive never develop any diseases associated with the gene, so it is possible to have it and never know about it.
What is meant by a gene skipping a generation is that it is actually there in the genome of the "skipped" individual but silent, that is, it´s effect cannot be seen. As mentioned above this is most often the case with HLA-B27. This individual´s child might then inherit the gene and be affected by it. A child cannot inherit a gene straight from a grandparent. A parent must have it in his or her own genome in order to pass it on to the next generation.