Causes Of Mosaic Down Syndrome: Symptoms, Diagnosis & Treatment

Mosaic Down syndrome is a chromosomal disorder. This genetic disorder contains two types of cells; there are some cells which contain normal 46 chromosomes, while some of them have an extra copy of 21st chromosome, meaning these cells have 47 chromosomes. For example the cells make that make up skin have 3 copies of chromosome while cells of other tissues and organs may be normal. In the same way the cell abnormality can be in any organ.

This abnormal chromosome in the cells can give rise to several symptoms that may cause physical as well as mental abnormality in the affected child or a person.

Mosaic down syndrome is a type of broadly defined Down’s syndrome. It is rare syndrome and often remains undetected as the symptoms are milder with good IQ of the child.

Pregnancy after the age of 35 years increases the probability of Down syndrome, which also includes mosaic variety. Couples having one child with Down syndrome has increased risk of another child with same condition. Although mosaic Down syndrome has milder or no features that are more prominently seen in Down syndrome, the treatment remains same as that of Down syndrome. It consists of physiotherapy, speech therapy, and various other cognitive therapies to improve the child’s mental ability.

Signs And Symptoms Of Mosaic Down Syndrome

Several abnormalities may occur with an extra copy of chromosome 21. There may be physical abnormal characteristics as well as impairment in cognitive abilities. However, since in mosaic Down’s syndrome not all cells are affected as a result many people with this condition may or may not exhibit all the symptoms as those produced in Down’s syndrome.

The symptoms are of milder intensity than trisomy 21 (Down syndrome). The common physical and mental characteristic features are:

  • Nasal bridge is flat.
  • Moon shaped face.
  • Muscle reflexes and tone is poor.
  • Eye slant in upward direction.
  • Very small chin.
  • Thick skin folds in the corner of eyes.
  • Neck is very short.
  • Absence of knuckle in fingers, especially in little finger.
  • Broad head.
  • White spots on iris, a part inside the eye.
  • Wide gap between two toes.
  • Hands and legs are short.
  • Short statured personality.
  • Stubborn.
  • Extremely impulsive.
  • Shy, avoids social engagement.
  • Always protrudes his tongue.
  • Mild mental retardation.
  • Speech abnormality.

There is increased risk of congenital heart ailment, vision problems, low thyroid function, early aging, epilepsy etc.

Diagnosis Of Mosaic Down Syndrome

Few decades ago, screening test was recommended in pregnant women above the age of 35 years. But now with new investigative tests, every pregnant woman is recommended to be screened for Down’s syndrome. Most tests are done in first three months of pregnancy. It includes ultrasonography, and blood tests.

In case if results are positive, than further diagnostic procedures such as amniocentesis, chorionic villi biopsy, and blood sample from umbilicus is done to confirm the diagnosis.

Treatment For Mosaic Down Syndrome

There is no major difference with treatment of mosaic Down syndrome as compared with Down syndrome. The main aim of management is to improve the quality of life of the growing child with help of several therapies. Slowly and gradually the child has improvement in his mental ability as well as motor skills. Improvement is promising if the treatment is begun in the early years.

With different programs, the child is able to speak well, improve his motor skills, improves his speech and IQ level. Together with all the therapies, the child must also eat nutritious diet and exercise regularly. These children have greater risk of weight gain.