Mosaic down syndrome; causes, symptoms, treatment, and prognosis

Mosaic down syndrome is a subcategory of down syndrome, accounting for only 2-4% of all down syndrome cases. It is a rare form of down syndrome in which patients have two different types of cells in their body, one type of cell is normal (containing 46 chromosomes) and the other type of cell is abnormal (containing 47 chromosomes, the 47^th chromosome being chromosome number 21); both types of these cells (abnormal and normal) are found as a mixture throughout the patient’s body. However, in the instance of non-mosaic down syndrome, a patient’s cells contain only one type of cell, cells with 47 chromosomes.

During early cell division, a misdivision occurs after fertilization of an egg cell. This misdivision results in mosaic down syndrome, where a person has a set of a normal number of chromosomes, and a set of chromosomes with an extra chromosome number 21. Usually, the chance of down syndrome occurrence in a baby is less than one percent. However, the chances of a baby developing down syndrome correlates to the age of the baby’s mother; a mother who is 35 years of age or older greatly increases the risk that her baby will have down syndrome if she is to conceive. This concept is primarily due to the fact that genes begin to deteriorate with age, and at 35 years and older, a mother’s genes have already started to deteriorate a while ago (around the age of 26).

The most common signs of a person with mosaic down syndrome are abnormal physical features, such as white patches in the iris of the eye, flat and straight hair, or a flat nasal bridge. Yet, beneath obvious signs on the surface, these patients typically suffer from either mild or moderate mental retardation.

Before treatment can begin, this genetic disorder must first be identified with a simple blood test; often, this blood test is a standard procedure during pregnancy. After identification, patients can undergo mental and physical therapy programs and special educational and vocational programs, as a means of coping with a cognitive learning disability.

Despite an unfair setback early in life, these patients can improve their cognitive function and live a life like any other human being, with the help of family, tutors, teachers, and friends. Success is not a reflection of where a person started from, it is a reflection of where they end up, and mosaic down syndrome patients can be as successful as anyone else.