What Is Trisomy 8 Mosaicism?
mosaicism syndrome (T8mS) is a condition that affects human chromosomes.
Specifically, people with T8mS have three complete copies (rather than the
typical two) of chromosome 8 in their cells. The extra chromosome 8 appears in
some of the cells, but not all. The symptoms of this syndrome vary
considerably, ranging from undetectable to, in some cases, severe.
chromosome in all cells is a condition called full or complete trisomy 8, which
is deadly and can cause miscarriage during the first trimester of pregnancy.
T8mS is a rare
disorder, affecting males more often than females.
What Causes Trisomy 8 Mosaicism?
mosaicism is caused by a problem between the sperm and egg in which some cells
don’t divide properly. The condition is a chance occurrence and is not
Symptoms of Trisomy 8 Mosaicism
Symptoms of T8mS
vary greatly. Some children born with T8mS have severe, highly visible physical
symptoms while others display no visible symptoms. Possible symptoms include:
- longer than average head
- wide, deep eyes
- thick lips
- large forehead
- narrow shoulders
- long torso
- narrow pelvis
- deep creases on the hands and feet
- palate (mouth) problems
- joint problems and stiffness
- spinal issues, such as scoliosis
- kidney problems
- heart issues
- bone and structure abnormalities
- underdeveloped genitals
- lack of intellectual development (in some but not all
Diagnosing Trisomy 8 Mosaicism
often goes undiagnosed, because there may be no detectable symptoms. In cases
where T8mS is suspected in an infant or adult, the doctor may take a blood or
skin sample and perform a cell analysis. This test does not determine the
severity of symptoms—rather, it just indicates whether or not it is present.
Treating Trisomy 8 Mosaicism
There is no cure
for trisomy 8 mosaicism, but some symptoms of the condition may be treated.
Treatment will vary depending on symptoms and severity. Symptoms with no
associated health problems (such as facial deformities) may be difficult to
Trisomy 8 Mosaicism Prognosis
If most or all
cells have the extra chromosome, this is a condition known as full or complete
trisomy 8. Full trisomy 8 is fatal, often leading to miscarriage in the first
trimester of pregnancy.>
People with only
some of the cells affected can live normal lifespans, as long as other
complications from the disorder don’t develop.
Those with T8mS
are more likely to develop Wilms’ tumors, a cancer of the kidneys of children.
Additionally, there is increased potential to develop myelodysplasias, which
are bone marrow conditions, and myeloid leukemia, a form of cancer that affects