Down's syndrome

Question 1

Mechanisms
1. Gamete non-[…] - most common, non-disjunction of chromosomes
- incidence of non-disjunction increases with maternal […].

2. Robertsonian translocation - aka […] Down syndrome or translocation Down syndrome
   - fusion of both […] arms
   - Maternal age does not influence the incidence of translocation.
3. Mosaic - 2 cell lines: 1 trisomy and 1 normal

Answer 1

disjunction, age

familial, long

Question 2

Down’s screening during pregnancy
1. What other trisomies

Answer 2

10-14 weeks
1. 13 (Patau) 18 (Edward’s)

Question 3

Features
- Upward-slanting palpebral fissures
- […] folds
-[…] tongue
- Small […]-set ears with adherent earlobes
- […] nasal bridge - broad and flat
- Small oral cavity
- Single transverse palmar […]
- Short stature
- Learning difficulties
- Congenital heart defects
- duodenal […]
- […] disease
- […]tonia

Answer 3

Epicanthal
Protruding
low
Hypoplastic
crease
atresia
Hirschprung’s
Hypotonia

Question 4

Common heart defects in DS

Answer 4

AVSD
VSD

Question 5

Later complications
- […]: males due to impaired spermatogenesis. Females usually […] + increased incidence of problems with pregnancy and labour
- repeated respiratory infections (+hearing impairment from […] […])
- acute […] leukaemia
- […]thyroidism
- Alzheimer’s disease
- atlantoaxial instability

Answer 5

subfertility, subfertile
glue ear
lymphoblastic
hypothyroidism