Germline mosaicism is one explanation for the transmission
of a genetic disorder to more than one offspring by apparently
normal parents. In these cases the mutation may be confined to
the germline cells or may be present in a proportion of somatic
cells as well. In Duchenne muscular dystrophy, it has been
calculated that up to 20% of the mothers of isolated cases,
whose carrier tests performed on leucocyte DNA give normal
results, may have gonadal mosaicism for the muscular
dystrophy mutation. The possibility of germline mosaicism
makes it difficult to exclude a risk of recurrence in other
X linked recessive disorders where the mother’s carrier tests
give normal results, and autosomal dominant disorders where
the parents are clinically unaffected.
Subscribe to:
Post Comments (Atom)
Here is a link to more information about the genetics of Germline Mosaicism that was prepared by our genetic counselor and which has links to some useful resource for those dealing with this condition: http://www.accessdna.com/condition/Germline_Mosaicism/162. There is also a number listed for anyone who wants to speak to a genetic counselor by phone. I hope it helps. Thanks, AccessDNA
ReplyDelete