Many cases of Wolf-Hirschhorn syndrome (WHS) (about 50-60%) are not inherited from a parent and are caused by a new (de novo) deletion of a region of chromosome 4 (called 4p16) that occurs for the first time in the person with WHS. In about 40-45% of cases, the person with WHS has an unbalanced translocation with both a deletion on chromosome 4 and an extra piece (trisomy) of part of another chromosome. In these cases, the unbalanced translocation may be de novo, or inherited from a parent who carries a balanced rearrangement (when parts of chromosomes are rearranged but there is no extra or missing genetic material).
Risks to family members and their children depend on whether the person with WHS has the syndrome due to a de novo deletion or an unbalanced translocation.
Last updated: 4/28/2017
What are the risks to family members of a person with Wolf-Hirschhorn syndrome?
Risks to family members and their children depend on the mechanism of how the deletion occurred in the person with Wolf-Hirschhorn syndrome (WHS).
The parents of a person with WHS are unaffected. However, in some cases, a parent has a balanced rearrangement (when chromosome material is rearranged but there is no extra or missing material) that resulted in the child having WHS. For this reason, it is recommended that the parents of a person with WHS have genetic testing to see if one carries a balanced rearrangement.
The risk to siblings of a person with WHS depends on the genetic status of the parents. If it is found that the deletion in the affected person is de novo (not inherited and occurring for the first time), the risk to siblings is negligible. If a parent carries a chromosome rearrangement, the siblings are at increased risk for a chromosome abnormality or rearrangement, and other family members are also at risk of carrying the rearrangement.
If a parent is known to be a carrier of a chromosome 4p rearrangement, prenatal testing via chorionic villus sampling or amniocentesis is possible, and preimplantation genetic diagnosis (PGD) may be an option.
People with specific questions about genetic risks or genetic testing for themselves or family members should speak with a genetics professional.
Last updated: 12/4/2014
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