MED1011-PCL-Week5

Home > MED 1011 > PCL

Patient Summary
Male baby born in an uncomplicated delivery with dusky colour, floppy, heart problems and unusual facial features. First child to 29 y/o mother and 31 y/o father. Mother an ex-smoker who was fit and well throughout pregnancy. No family history and pre-natal tests not undertaken.

Dx = **Down syndrome**

__Definition/Incidence__
· Down syndrome – trisomy 21 · 1/700 live births · Most common cause of intellectual disability · Incidence increases with older maternal age and if previous child with DS

__Genetics__
· **95% trisomy 21** o 95% have extra chromosome from maternal side · **3-4% Rb translocation** (fusion of chromosomes 14 and 21) o Only inheritable form · **Remainder – mosaicism** o Some cell lines normal, some trisomy 21

__Signs/Symptoms__
· **Characteristic physical features** – flat facial profile with upward slant to eyes, small ears and mouth, single palmar crease, low muscle tone, slower growth rate · **Some degree of intellectual disability** · More than 50 possible characteristics

__Diagnosis__
· Screening o Maternal serum test: measures levels of markers in mother’s blood (hCG, inhibin, PAPPA) o Ultrasound – look for thickened nuchal fold / nuchal transparency · Diagnostic o Amniocentesis and chorionic villus sampling

__Complications/Prognosis__
· **Congenital heart defects** (30-50%) · Other medical conditions associated with DS include cataracts, GI blockages, hearing problems, hip dislocation, sleep apnoea, hypothyroidism · Often experience early onset Alzheimer’s

__Psycho-Social Considerations__
· Support services · Reaction to disability can be different between family members, cultures, etc. · Financial, time and emotional burden of having child with a disability