Down syndrome – Basics
What is Down syndrome?
Down Syndrome (DS) is a genetic disorder due to chromosomal number alteration. The other name of this disease is Trisomy 21. Here, an additional copy of chromosome number 21 is present.
Incidence
The worldwide incidence of Down Syndrome is 1.5 per 1000 live birth.
Increased maternal and paternal age plays a pivotal role in Down syndrome.
The incidence of Down syndrome increase with the progression of maternal age.
The probability increases from less than 0.1% in 20-year-old mothers to 3% in 45-year-old mothers.
Features
Face:
Flat occiput
Single palmar crease
Marked ‘sandal gap’ between the big toe and first toe
Decreased muscle tone
Short stature
Upslanting palpebral fissures
Epicanthic folds
Brushfield spots in the iris
Tongue protrusion
Low set small ears
Flat or round face
Complications
Cardiac
Neurological
Others
Ventricular septal defect (the most common cardiac problem)
Cushion defect of the endocardium
Tetralogy of Fallot (TOF)
Ostium secundum atrial septal defect (ASD)
Patent ductus arteriosus (PDA)
Learning difficulty
Alzheimer’s disease
Acute lymphoblastic leukemia
Recurrent respiratory infection
Hypothyroidism
Male infertility
Female subfertility
Atlantoaxial instability
Diagnosis
Screening
Diagnostic
Blood test – pregnancy-associated plasma protein-A (PAPP-A)
Nuchal translucency test
Chorionic villus sampling
Amniocentesis
Treatment
No definitive treatment has been yet established.
Symptomatic and interventional treatments are given for associated critical conditions. Usually, the multi-disciplinary medical team is needed.
Support groups.
Life expectancy
Around 20% of patients die within the 1st year.
45% may survive up to 60 years.
