Genetics Flashcards
Define Down’s Syndrome
Genetic condition caused by three copies of chromosome 21 - trisomy 21
Typical features in Down’s syndrome
Hypotonia
Bradycephaly
Short neck
Short stature
Flattened face and nose
Prominent epicanthic folds
Upward sloping palpebral fissures
Single palmar crease
Complications of Down’s syndrome
Learning disability
Recurrent otitis media
Feadness - eustachian tube defects
Visual problems - myopia, strabismus and cataracts
Hypothyroidism
Cardiac defects - ASD, VSD, patent ductus arteriosus and tetralogy of fallot
Atlantoaxial instability
Leukaemia
Dementia
When is a combined screen carried out
Between 11 and 14 weeks
What is assessed in combined screen
Looking for downs
US measure of nuchal translucency - increased
Beta-HCG - increased
Pregnancy associated plasma protein - decreased
What is assessed in the tripple test
Looking for Downs
Beta-HCH - increased
Alpha-fetoprotein - decreased
Serum oestriol - decreased
When is a triple test done
14-20 weeks
What is assessed in a quadruple test
Looking for Downs
Beta-HCH - increased
Alpha-fetoprotein - decreased
Serum oestriol - decreased
Inhibin-A
When is a quadruple test done
14-20 weeks
When are amniocentesis and CVS offered
When risk of Downs is greater the 1 in 150
When can CVS be done
Before 15 weeks -
Management of Downs syndrome
MDT!
Thyroid checks
Echocardiogram
Audiometry
Eye checks
Define Klinefelter syndrome
Occurs where a male has an additional X chromosome - 47 XXY
Typical features of Kleinfelter syndrome
Devlop features at puberty
Taller
Wider hips
Gynaecomastia
Weaker muscles
Small testicles
Reduced libido
Shyness
Infertility
Subtle learning difficulties
Management of Kleinfelter syndrome
No cure
Testosterone injections
Advanced IVF techniques
Breast reduction
Speech and language
Occupational therapy
Physio
Educational support
Define Turner syndrome
Occurs when a female has a single X chromosome - 45 XO
Classic features of Turner syndrome
Short stature
Webbed neck
Widely spaced nipples
High arching palate
Downward sloping eyes with ptosis
Broad chest
Cubitus valgus - arms out at elbows
Underdeveloped ovaries with reduced function
Late or incomplete puberty
Infetile
What conditions are associated with Turner syndrome
Recurrent otitis media
Recurrent UTI
Coarctation of the aorta
Hypothyroidism
Hypertension
Obesity
Diabetes
Osteoporosis
Various specific learning disabilities
Management of Turner syndrome
Growth hormone therapy
Oestrogen and progesterone replacement - sex characteristics, regulate menstrual cycle
Fertility treatment
Define Noonan syndrome
Genetic condition predominantly caused by autosomal dominant variation
Classic features of Noonan syndrome
Short stature
Broard forehead
Downward sloping eyes with ptosis
Hypertelorism - wide eye spacing
Prominent nasolabial folds
Low set ears
Webbed neck
Widely spaced nipples
Conditions associated with Noonan syndrome
Congenital heart disease - pulmonary valve stenosis, hypertrophic cardiomyopathy, ASD
Crytorchidism
Learning disability
Bleeding disorders
Lymphoedema
Leukaemia and neuroblastoma
Define Marfan syndrome
An autosomal dominant condition affecing the gene responsible for creating fibrillin - an important component of connective tissue
Classic features of Marfan syndrome
Tall stature
Long neck
Long limbs
Long fingers
High arching palate
Hypermobility
Pectus carinatum or pectus excavatum
Downward sloping palpable fissure
Conditions associated with Marfans syndrome
Lens dislocation in the eye
Joint dislocations and pain due to hypermobility
Scoliosis
Pneumothorax
GORD
Mitral valve prolapse
Aortic valve prpolapse
Aortic aneurysms
Define fragile X syndrome
Caused by a mutation in the FMR1 gene on the x chromosome - plays a role in cognitive development
X linked - dominant or recessive
Classic features of Fragile X syndrome
Intellectual disability
Long narrow face
Large ears
Large testicles after puberty
Hypermobility - esp hands
ADHD
Autism
Seizures
Define Prader Willi syndrome
A genetic condition caused by the loss of functional genes on the proximal arm of chromosome 15
Due to a deletion
Classic features of Prader-Willi syndrome
Constant insatiable hunger - obesity
Poor muscle tone
Mild-moderate learning disability
Hypogonadism
Fairer soft skin
Prone to bruising
Mental health issues - anxiety
Dysmorphic features
Narrow forehead
Almond shaped eyes
Strabismus
Thin upper lip
Downturned mouth
Management of Prader-Willi syndrome
Locking cupboards
Growth hormone - improves muscle development
Supportive care
Define Angelman syndrome
A genetic condition caused by loss of function of the UBE3A gene - inherited from the mother - deletion on chromosome 15
Classic features of Angelman syndrome
Fascination with water
Happy demeanour
Widely spaced teeth
Delayed development - esp speech
Coordination and balance problems
Inappropriate laughter
Hand flapping
Abnormla sleep
Epilepsy
ADHD
Dysmorphic features
Microcephaly
Fair skin
Light skin
Wide mouth
Define William syndrome
Caused by random deletion of genetic material on one copy of chromosome 7
Classic features of William syndrome
Very sociable
Broad forehead
Starburst eyes
Associated with supravalvular aortic stenosis
Flattened nasal bridge
Long philtrum
Wide mouth with widely spaced teeth
Small chin
