2 deletion is almost as common as Trisomy 21, also known as Down syndrome, which is a more widely recognized chromosomal disorder. Children with 22q11. 2 deletion and duplication syndromes often have other health problems, including: Heart defects.

Trisomy 21. About 95 percent of the time, Down syndrome is caused by trisomy 21 — the person has three copies of chromosome 21, instead of the usual two copies, in all cells. This is caused by abnormal cell division during the development of the sperm cell or the egg cell.

Most cases of Down syndrome are not inherited. When the condition is caused by trisomy 21, the chromosomal abnormality occurs as a random event during the formation of reproductive cells in a parent. The abnormality usually occurs in egg cells, but it occasionally occurs in sperm cells.

At birth, babies with Down syndrome usually have certain characteristic signs, including:

• flat facial features.
• small head and ears.
• short neck.
• bulging tongue.
• eyes that slant upward.
• atypically shaped ears.
• poor muscle tone.

A Detailed Anomaly Scan done at 20 weeks can only detect 50% of Down Syndrome cases. First Trimester Screening, using bloods and Nuchal Translucency measurement, done between 10-14 weeks, can detect 94% of cases and Non-invasive Prenatal Testing (NIPT) from 9 weeks can detect 99% of Down Syndrome cases.

Here’s what to know about them. Maternal Age: Down syndrome can occur at any maternal age, but the possibility increases as a woman gets older. A 25-year-old woman has a one in 1,200 chance of having a baby with Down syndrome. By 35 years of age, the risk increases to one in 350—and it becomes one in 100 by age 40.

Conclusion: Pharmacologic doses of folic acid and iron appear to have a preventive effect against Down’s syndrome.