Paed:Genetics Flashcards
What is Klinefelters Syndrome?
47, XXY (extra X chromosome)
Features of klinefelters?
Infertility Hypogonadism with small testes Gynaecomastia in adolescence Tall stature Intelligence normal or decreased
What is Turners Syndrome?
45, X (missing X or Y).
Usually results in early miscarriage and detected by fetal uss showing oedema.
Clinical features of Turners?
Lymphoedema of hands and feet in neonate Spoon shaped nails Short stature (cardinal feature) neck webbing wide carrying angle wide spaced nipples Coarctation of aorta Delayed puberty ovarian dysfunction renal anomalies millie has this lol hypothyroidism
What is Downs syndrome?
Trisomy 21
Clinical features of T21?
Severe learning difficulties
Facial abnormalities: round face, flat nasal bridge, upslanted palpebral fissures, epicanthic folds, small mouth
fkat occiput
single palmar creases
incurved fifth finger
wide sandal gap between second and third toe
Diagnosis of T21
Blood analysis by fluroscent in situ hybridisation(FISH
What kills downs?
Congenital heart disease. Particularly AVSD
How does the extra chromosome come about?
Meiotic non disjunction (94%)
Translocation (5%)
Mosaicism
What is edwards syndrome?
Trisomy 18.
How to confirm edwards and pataus?
Chromosomal analysis
How to confrim edwards in utero?
Amnioscentesis
What is pataus syndrome?
Trisomy 13
Features of edwards?
LBW Prominent occiput small mouth and chin small sternum rocker bottom feet cardiac and renal malformation
Features of pataus?
Structural defect of brain scalp defect small eyes defects in eye cleft lip and palate polydactyl cardiac and renal malfromations
What is Prader Willi syndrome?
Cytogenic deletion of chromosme 15q OR uniparental deletion of chromosome 15.
Clinical features of prader willi
Neonatal hypotonia and poor feeding moderate mental retardation hyperphagia obesity small genitalia
Clinical features of Angelmans syndrome?
Unprovoked laughing and clapping (happy puppet) microcephaly mental retardation seizures ataxia broad based gait
What is Fragile X? With signs
(also known as Martin Bell) Delayed speech and language Delayed motor milestones low iq hyperactivity emotional and behavioural problems Physical features: long narrow face, large ears, prominent jaw, big testes
What is Noonan syndrome?
A multisystem disorder characterised by short stature and characteristic facial features: ptosis, down slanting eyes, low set ears, congenital heart defects (hypertrophic cardiomyopathy and pulm stenosis) +/- chest and spine deformities, webbed neck, clotting disorders, learning disabilities
What is Duchennes Muscular Dystrophy?
Mutations in dystrophin gene results in near total loss of dystrophin, the muscles get replaced by fibro-adipose tissue.
Presentation of DMD?
Boys aged 1-6 years w/ waddling clumsy gait and the classical gowers manoeuvre.
What is the Gowers manoeuvre?
Using hands to climb up legs on standing.
Complications of DMD?
Respiratory impairment and infections
cardiomyopathy
orthopaeid complications
Investigations of DMD?
Creatinine kinase raised
measure this in all boys not walking by 18months
Do muscle biopsy to see abnormal fibres surrounded by fatty fibrous tissue.
Treatment of DMD?
Prednisolone slows decline in strength.
What causes Williams Syndrome?
Microdeletion of chromosome 7q11 that encompasses the elastin gene.
What are the facial features in Williams syndrome?
Periorbital fullness, full cheeks, antiverted nares, wide mouth and full lips, small widely spaced teeth.
What cardiac defect is associated with Williams syndrome?
Supravalvular aortic stenosis.
often with peripheral pulmonary branch stenosis.
Behaviour of williams syndrome ppl?
Overfriendly, short attention span, anxiety, most have mild mental retardation, good language but poor visuospatial skills.
How is williams syndrome diagnosed?
FISH study for the 7q11 microdeletion.
