Overview Of Trisomy 13 Syndrome
Trisomy 13 syndrome (also called Patau syndrome) is a genetic disorder in which a person has 3 copies of genetic material from chromosome 13, instead of the usual 2 copies. Rarely, the extra material may be attached to another chromosome (translocation).
Commonly Associated With
Causes Of Trisomy 13 Syndrome
Trisomy 13 syndrome occurs when extra DNA from chromosome 13 appears in some or all of the body’s cells.
Trisomy 13: the presence of an extra (third) chromosome 13 in all of the cells.
Mosaic trisomy 13: the presence of an extra chromosome 13 in some of the cells.
Partial trisomy 13: the presence of a part of an extra chromosome 13 in the cells.
The extra material interferes with normal development.
Trisomy 13 occurs in about 1 out of every 10,000 newborns. Most cases are not passed down through families (inherited). Instead, the events that lead to trisomy 13 occur in either the sperm or the egg that forms the fetus.
Symptoms Of Trisomy 13 Syndrome
- Cleft lip or palate
- Clenched hands (with outer fingers on top of the inner fingers)
- Close-set eyes — eyes may actually fuse together into one
- Decreased muscle tone
- Extra fingers or toes (polydactyly)
- Hernias: umbilical hernia, inguinal hernia
- Hole, split, or cleft in the iris (coloboma)
- Low-set ears
- Intellectual disability, severe
- Scalp defects (missing skin)
- Single palmar crease
- Skeletal (limb) abnormalities
- Small eyes
- Small head (microcephaly)
- Small lower jaw (micrognathia)
- Undescended testicle (cryptorchidism)
Exams & Tests
The infant with trisomy 13 syndrome may have a single umbilical artery at birth.
There are often signs of congenital heart disease, such as:
- Abnormal placement of the heart toward the right side of the chest instead of the left
- Atrial septal defect
- Patent ductus arteriosus
- Ventricular septal defect
- Gastrointestinal x-rays or ultrasound may show the rotation of the internal organs.
MRI or CT scans of the head may reveal a problem with the structure of the brain. The problem is called holoprosencephaly. It is the joining together of the 2 sides of the brain.
Chromosome studies show trisomy 13, trisomy 13 mosaicism, or partial trisomy.
Treatment Of Trisomy 13 Syndrome
There is no specific treatment for trisomy 13. Treatment varies from child to child and depends on the specific symptoms.