Translocation

Reciprocal Autosomal Translocation

represent one of the most common structural rearrangements observed in man. Estimates of the population frequency range from 1/673 to 1/1,000.

A reciprocal translocation forms when two different chromosomes exchange segments

The (11;22) Translocation

breakpoints within bands 11q23.3 and 22q11.2, is unique because it represents the first recognized recurring constitutional reciprocal translocation in man.

In 2004, the condition was named Emanuel syndrome, to honor the work of Dr. Beverly Emanuel

Balanced carriers of the (11;22) translocation are phenotypically normal.

Severe mental retardation, congenital heart disease, microcephaly, malformed ears with preauricular skin tags and/or pits, a high-arched or cleft palate, micrognathia, anal stenosis or atresia, kidney anomalies, and genital abnormalities in males are common features shared by these unbalanced (11;22) segregants.

The (4;8) Translocation

At least 18 unrelated families with similar (4;8)translocations,or a chromosome derived from this translocation, have been reported.

4p16 and 8p23 breakpoints

these patients are clinically indistinguishable from Wolf-Hirschhorn patients

The (8;22) Translocation

At least 12 families with a recurring (8;22) translocation involving breakpoints at 8q24.1 and 22q11.21 have been identified.

The phenotype associated with this imbalance is variable but is most often associated with a normal birth weight and normal subsequent growth, mild developmental delays and/or mild mental retardation, prominent ears with preauricular pits, and clinodactyl

Robertsonian Translocation

occurs when the long arms of any two acrocentric chromosomes join to produce a single metacentric or submetacentric chromosome

Jumping Translocations

refers to dynamic or changing translocations that are rarely observed in constitutional karyotypes.

It is used most often to describe a type of mosaicism in which a specific donor chromosome segment is translocated to two or more different recipient sites over the course of multiple mitotic cell divisions.