Can karyotyping detect unbalanced translocation?

Results. In the 1294 cases of POCs, we detected CNVs of terminal duplication and deletion that imply unbalanced translocation derivatives in 16 cases, and accurate diagnosis with the parental study was made in all the cases by karyotyping and/or FISH.

What is an unbalanced translocation?

An unbalanced translocation occurs when a fetus inherits a chromosome with extra or missing genetic material from a parent with a balanced translocation.

What does a unbalanced translocation cause?

Unbalanced translocations This is called a ‘de novo’ (from Latin) or new rearrangement. In this case the parents are unlikely to have another child with a translocation. A child who has an unbalanced translocation may have learning disabilities, developmental delay and health problems.

What can karyotyping detect?

Karyotypes can reveal changes in chromosome number associated with aneuploid conditions, such as trisomy 21 (Down syndrome). Careful analysis of karyotypes can also reveal more subtle structural changes, such as chromosomal deletions, duplications, translocations, or inversions.

What is the difference between balanced and unbalanced translocation?

Translocations can be balanced (in an even exchange of material with no genetic information extra or missing, and ideally full functionality) or unbalanced (where the exchange of chromosome material is unequal resulting in extra or missing genes).

How common is unbalanced translocation?

To date, 50 samples have been tested by NIPT where one parent carries a balanced reciprocal translocation (32 cases) or a Robertsonian translocation (18 cases). Seven of 32 pregnancies (22%) have been identified as being at increased risk for an unbalanced reciprocal translocation.

Is Robertsonian translocation balanced or unbalanced?

The Robertsonian translocation is unbalanced and the baby has three copies of the long arm of chromosome 21 instead of two. This causes a type of Down’s syndrome called translocation Down’s syndrome. The effects on the baby are exactly the same as when Down’s syndrome is caused by having an extra entire chromosome 21.

How common are unbalanced chromosomal rearrangements?

Abstract. Unbalanced chromosomal rearrangements are not common; however, they have a significant clinical expression. The parental balanced translocation produces unbalanced chromosome, which is transmitted to next generation through fertilization of gametes carrying the derivative chromosome.

What is unbalanced translocation of the cerebellum?

The unbalanced translocation involves a 7.1 Mb loss of the terminal portion of 10q, and a 4.2Mb gain of 11q. One of the brothers also developed a cerebellar juvenile pilocytic astrocytoma. The father was found to be a balanced carrier and the couple had a previous miscarriage.

Is there an unbalanced translocation of the terminal portion of 10q?

DISCUSSION We present a pedigree with an unbalanced translocation involving a 7.1Mb loss of the terminal portion of 10q and a 4.2 Mb gain of 11q, associated with development of ASD and cerebellar juvenile pilocytic astrocytoma.

What are the indications for amniocentesis in reciprocal translocations?

For individual types of reciprocal translocations (balanced and unbalanced), except for the presence of abnormal biochemical markers in maternal serum, both AMA and a parent with an abnormal karyotype were primary indications for amniocentesis.