Translocation risk estimates The Genetics Center, Inc.

The Genetics Center, Inc. Address, phone, and fax

Translocation Risk Estimates:

This is a service to clinical
genetics professionals only.

Balanced chromosome translocations in normal individuals, depending on the exact nature of the translocation, may have significant implications for reproduction. Problems include infertility, pregnancy loss, and having children with serious birth defects due to unbalanced chromosome complements. Dr. Carolyn Trunca, a clinical cytogeneticist and presently the laboratory director of The Genetics Center, has developed a model for calculating reproductive risks (of miscarriage and of a live born baby with an unbalanced chromosome complement) for translocation carriers. The model is based on analysis of a large data set collected from over 900 translocation families.

Please note that the only translocations for which this model predicts risks are balanced, reciprocal translocations. The model is not applicable to Robertsonian translocations, inversions, de novo translocations, sex chromosome rearrangements, and translocations involving more than two chromosomes.

Information required to estimate translocation carrier risks:

First, in determining risks for a translocation carrier, it is essential to consider how the translocation was initially ascertained. Typical reasons for ascertainment include:

Prenatal diagnosis for an unrelated reason (i.e. maternal age)

Blood chromosome studies because of multiple pregnancy loss or infertility

Birth of a child with a balanced or unbalanced chromosome translocation

A translocation identified on products of conception that was inherited from a parent

Next, the chromosomes and the breakpoints must be determined. Lastly, it is helpful to have obtained as complete a family history as possible and identify any outcomes that may be related to the translocation, such as children who may have an unbalanced chromosome complement and a history of pregnancy loss or infertility.

To obtain translocation risk estimates:

Please print our translocation information request form and fax it to our office before contacting Dr. Trunca by telephone. That single sheet is usually all that is necessary.

Contact Dr. Carolyn Trunca directly at The Genetics Center. Since we are offering this as a free service to the genetics community, we are unable to return phone or fax messages or provide written information to you or your patients.

Dr. Trunca is generally available between noon and 5PM weekdays.

Please do not have patients contact Dr. Trunca directly for this information.

Revised April 19, 2013