Genetics Flashcards
Down’s syndrome features
flat occiput, third fontanelle
small ears, short neck
hypotonia
single palmar crease, incurved 5th finger
wide sandal gap
facial appearance: up slanted palpebral fissures , round nose, flat nasal bridge, small mouth, protruding tongue
Down’s syndrome: associated congenital problems
AVSD, VSD, PDA
Duodenal atresia
Hirspung’s disease
Down’s later problems
learning difficulties, delayed development increased risk of infections, leukaemia, hypothyroidism, coeliac disease hearing impairment (otitis media) visual impairment (cataracts) acquired hip dislocation obstructive sleep apnoea epilepsy early onset Alzheimer disease
Pathophysiology of trisomies
meiotic non-disjunction (chromosome pair fails to separate
translocations (robertsonian translocation)
Mosaicism
Turner’s syndrome clinical features
normal intellect short stature webbed neck recurrent otitis media pigmented moles organ dysgenesis -> infertility delayed puberty
Turner’s synd associated problems
recurrent otitis media hypothyroidism infertility delayed puberty cong heart defects
Turner’s synd congenital heart defects
lt sided
CoA
aortic stenosis
Turner’s syndrome cytogenetics
45, X
Duchenne muscular dystrophy
progressive muscular degeneration X-linked (1/3 are de novo) dystrophin gene deletion -> calcium influx -> myofibril necrosis -> CK increase
Duchenne muscular dystrophy clinical features
waddling gait language delay gower's sign calf pseudo hypertrophy learning difficulties (1/3) scoliosis
Patau syndrome cytogenetics
trisomy 13
Patau syndrome features
microcephaly small eyes cleft palate polydactylyl complex congenital heart defects
Edwards syndrome cytogenetics
trisomy 18
Edwards syndrome features
small jaw low set ears rocket bottom feet overlapping fingers complex congenital heart problems
Fragile X features
learning difficulties macrocephaly long face large ears macro-orchidism
