Ring chromosome 14 syndrome
Ring chromosome 14 syndrome is a very rare human chromosome abnormality. It occurs when one or both of the telomeres that mark the ends of chromosome 14 are lost, allowing the now uncapped ends to fuse together – thus forming a ring chromosome. It causes a number of serious health issues.
Symptoms and signs
The most common symptoms are intellectual disability and recurrent seizures developing in infancy or early childhood. Typically, the seizures are resistant to treatment with anti-epileptic drugs. Other symptoms may include:- Microcephaly
- Lymphedema
- Facial abnormalities
- Immune deficiencies
- Abnormalities of retina
- Slow growth
- Short stature
Cause
The syndrome is caused by the loss of genetic material near the end of the long arm of chromosome 14. The break that causes the telomere to be lost occurs near the end of the chromosome, and is called a constitutional ring. These rings arise spontaneously.The genetic abnormality occurs randomly in sperm or egg cells or it may occur in early embryonic growth, if it occurs during embryonic growth the ring chromosome may be present in only some of a person's cells.