A chromosome translocation is a chromosome abnormality caused by the rearrangement of genetic material between different numbered (also called non-homologous) chromosomes.
Chromosome translocations can be characterized as balanced or unbalanced.
- A balanced translocation involves an apparently even exchange of genetic material resulting in no loss or gain of total genetic information. A balanced translocation does not typically result in physical and/or mental abnormalities.
- An unbalanced translocation involves an uneven exchange of genetic material resulting in a gain or loss of total genetic information. An unbalanced translocation is more likely to result in physical and/or mental abnormalities.
There are two main types of translocations: reciprocal and Robertsonian.
- Reciprocal translocations typically involve an exchange of genetic material between non-homologous chromosomes and are found in about 1 in 600 newborns.
- Robertsonian translocations involve the fusion of acrocentric chromosomes near the centromere with the loss of the p (short) arm. Acrocentric autosomal chromosomes include chromosomes 13, 14, 15, 21, and 22. The chromosome analysis of a person with a balanced Robertsonian translocation would reveal 45 chromosomes since two of the chromosomes have fused together. The most common Robertsonian translocation is found is about 1 in 1300 people and involves chromosomes 13 and 14.
When there is a parental chromosome translocation, the risk to have an abnormal child or adverse pregnancy outcome is dependent upon the specific translocation and family history and in some cases, which parent (mom or dad) has the translocation. We strongly recommend that you and your spouse meet with a genetic counselor who can review your family history, chromosome analyses and provide a more accurate risk assessment. You can find a genetic counselor by going to the National Society of Genetic Counselors website or through companies like mine, AccessDNA.
I am so sorry for all of your losses. I just suffered my 4th loss at 5 months. I'm guessing your wife also had to deliver. If so, I know how horrible it is. I just got tested for the exact same thing and I'm awaiting a response.