This site is intended for healthcare professionals
Last reviewed dd mmm yyyy. Last edited dd mmm yyyy
In 1887 Landon-Down described a syndrome of mental handicap associated with various physical abnormalities and a supposed resemblance to members of the Mongol race. This unfortunately led to this condition becoming known as mongolism but the condition is now known as Down's syndrome or trisomy 21.
A third copy of chromosome 21, trisomy 21, has long been recognized as the cause of Down's Syndrome
Down’s syndrome is the most common chromosomal disorder and was prenatally diagnosed in about 2.7 in 1,000 pregnancies in England and Wales in 2013 (1)
The incidence of Down's syndrome, as with other trisomic abnormalities, increases with maternal age. The number of live births to women aged 40+ has doubled, with a 6% increase in fertility seen in 2006 (2).
Note however that mothers of any age can have infants with Down's syndrome and the majority of Down's syndrome babies are born to younger mothers.
In 2018/2019 a new Non-Invasive Prenatal Test (NIPT) was rolled-out in the NHS, with the aim to reduce the number of women who have invasive tests.
Women with a chance equal or greater than 1 in 150 of having a baby with Down’s syndrome, Edwards’ syndrome or Patau’s syndrome are offered the additional option of NIPT. NIPT involves taking a blood sample from the mother and there is no risk of miscarriage (1)