Down's Syndrome

Question 1

What is Down’s syndrome?

Answer 1

Down’s syndrome, also known as trisomy 21, is the most common congenital chromosomal abnormality, occurring in about 1 in 800 to 1 in 1000 live births. It results from the presence of an extra copy of chromosome 21, leading to characteristic phenotypic features and increased morbidity through its effect on multiple organ systems.

Question 2

What is the most common cause of Down’s syndrome?

Answer 2

The majority of cases (95%) result from meiotic non-disjunction of the maternal chromosome 21.

Question 3

What is the risk factor for Down’s syndrome?

Answer 3

Maternal age is the strongest risk factor. For example, at age 35, the risk is 1 in 385; at age 40, it is 1 in 110.

Question 4

What are some common dysmorphic features of individuals with Down’s syndrome?

Answer 4

General: Hypotonia, hyperflexibility.
- Head: Oblique palpebral fissures, epicanthic folds, flat nasal bridge, brachycephaly, low-set ears, open mouth with protruding tongue, high arched palate.
- Neck: Short with excessive nape skin.
- Hands: Transverse palmar crease, short/in-curved little finger.
- Feet: Large gap between first and second toes.

Question 5

What is the most common congenital heart defect in Down’s syndrome?

Answer 5

The most common congenital heart defect is the complete atrioventricular septal defect (AVSD), present in approximately 37% of neonates with Down’s syndrome.

Question 6

What are other common congenital heart defects associated with Down’s syndrome?

Answer 6

Other common congenital heart defects include ventricular septal defect (31%) and atrial septal defect (15%).

Question 7

What neurological conditions are associated with Down’s syndrome?

Answer 7

Individuals with Down’s syndrome often experience developmental delay and intellectual disability. There is also an increased prevalence of autism, ADHD, and aggressive behavior. Additionally, Alzheimer’s disease can develop in up to 75% of individuals by the sixth decade.

Question 8

What respiratory conditions are more common in individuals with Down’s syndrome?

Answer 8

There is a higher incidence of asthma and obstructive sleep apnoea.

Question 9

What gastrointestinal anomalies are associated with Down’s syndrome?

Answer 9

Approximately 12% of individuals have gastrointestinal anomalies such as duodenal atresia, imperforate anus, tracheo-oesophageal fistula, and Hirschsprung disease.

Question 10

What is the prevalence of congenital heart disease in individuals with Down’s syndrome?

Answer 10

About 50% of neonates with Down’s syndrome have congenital heart disease.

Question 11

How does Down’s syndrome affect life expectancy?

Answer 11

With appropriate medical care, many individuals with Down’s syndrome live into their 60s and beyond.

Question 12

What is the role of early intervention in Down’s syndrome?

Answer 12

Early intervention programs focusing on speech, physical, and occupational therapies can significantly improve developmental outcomes.

Question 13

Are there any screening tests available for Down’s syndrome during pregnancy?

Answer 13

Yes, antenatal screening tests such as the combined test (first trimester) and quadruple test (second trimester) can assess the risk of Down’s syndrome.

Question 14

What is the combined test for Down’s syndrome screening?

Answer 14

The combined test assesses the chance of the fetus having Down’s syndrome by using maternal age, free beta human chorionic gonadotropin (bhCG), and nuchal translucency measurement.

Question 15

What is the quadruple test for Down’s syndrome screening?

Answer 15

The quadruple test is offered to women presenting between 14+2 and 20+0 weeks gestation or if the nuchal translucency measurement as part of the combined test cannot be obtained. It uses maternal age, free beta hCG, alpha-fetoprotein (AFP), and inhibin-A levels.

Question 16

What is the role of non-invasive prenatal testing (NIPT) in Down’s syndrome screening?

Answer 16

NIPT is a blood test for placental DNA that has a high detection rate (99% for trisomy 21). Positive results need confirmation with diagnostic testing.

Question 17

What are the diagnostic tests for Down’s syndrome?

Answer 17

Diagnostic tests include chorionic villus sampling (CVS) and amniocentesis, both involving needle sampling with a risk of miscarriage.

Question 18

What is the role of the anomaly scan in Down’s syndrome detection?

Answer 18

The anomaly scan, performed at 18+0 to 20+6 weeks, can detect physical conditions associated with Down’s syndrome.

Question 19

How does maternal age affect the risk of Down’s syndrome?

Answer 19

The risk increases with maternal age; for example, at age 35, the risk is 1 in 385, and at age 40, it is 1 in 110.

Question 20

What is the significance of epicanthic folds in Down’s syndrome?

Answer 20

Epicanthic folds are a characteristic facial feature of Down’s syndrome, contributing to the distinctive appearance.

Question 21

How does hypotonia present in infants with Down’s syndrome?

Answer 21

Hypotonia, or decreased muscle tone, is common in infants with Down’s syndrome, leading to a “floppy” appearance.

Question 22

What is the significance of a transverse palmar crease in Down’s syndrome?

Answer 22

A transverse palmar crease is a common hand feature in Down’s syndrome, often referred to as a “simian crease.”

Question 23

How does the presence of an extra chromosome 21 affect development in Down’s syndrome?

Answer 23

The additional genetic material from chromosome 21 leads to developmental delays, intellectual disability, and various physical anomalies.

Question 24

What is the role of genetic counseling in Down’s syndrome?

Answer 24

Genetic counseling provides information and support to families regarding the risks, diagnosis, and implications of Down’s syndrome.

Question 25

How does Down’s syndrome affect fertility?

Answer 25

While individuals with Down’s syndrome can have children, women with Down’s syndrome have a reduced fertility rate, and men are often infertile.

Question 26

What is the prevalence of hearing loss in individuals with Down’s syndrome?

Answer 26

Hearing loss is common in individuals with Down’s syndrome, often due to middle ear infections and structural abnormalities.

Question 27

How does Down’s syndrome affect vision?

Answer 27

Individuals with Down’s syndrome are at increased risk for vision problems, including strabismus, refractive errors, and cataracts.

Question 28

What is the role of early screening for congenital heart defects in Down’s syndrome?

Answer 28

Early screening and diagnosis of congenital heart defects allow for timely interventions, improving outcomes for individuals with Down’s syndrome.

Question 29

How does Down’s syndrome affect dental health?

Answer 29

Individuals with Down’s syndrome may have dental anomalies such as delayed eruption, malocclusion, and periodontal disease.

Question 30

What is the role of physical therapy in managing Down’s syndrome?

Answer 30

Physical therapy helps improve muscle strength, coordination, and motor skills, addressing the hypotonia commonly seen in Down’s syndrome.

Question 31

How does Down’s syndrome affect speech and language development?

Answer 31

Speech and language development may be delayed, and individuals may benefit from speech therapy to enhance communication skills.