Paeds genetics Flashcards
What is Down’s syndrome?
- Trisomy 21
What are the physical features of Down’s syndrome?
- flat face and nose
- upward slanting eyes
- hypotonia
- brachycephaly (small head with flat back)
- short stature
- single palmar crease
What routine investigations do children with Down’s syndrome undergo?
- thyroid checks
- echocardiogram
- audiometry
- eye tests
What are the options for antenatal testing for Down’s?
- Chorionic villus sampling: US guided biopsy of placental tissue (before 15 weeks)
- amniocentesis: US guided aspiration
What other conditions are associated with Down’s syndrome?
- AVSD
- duodenal atresia
- thyroid conditions
- sleep apnoea
- learning disability
- alzheimer’s
- ALL
What is the combined test?
- performed 11-14 weeks gestation
- ultrasound measures thickened nuchal translucency
- high β-HCG and low PAPPA in bloods
What is the triple test for Down’s?
- performed 14-20 weeks gestation
- β-HCG: high
- AFP: low
- serum estriol: low
What additional factor does the quadruple test measure?
- inhibin A: high
When is antenatal testing for Down’s offered?
- when risk result from screening is greater than 1 in 150
What are the genetics of Turner syndrome?
- female has single X chromosome
- makes 45XO
What are the features of Turner syndrome?
- short stature
- webbed neck
- broad chest and widely spaced nipples
- cubitus valgus
- high arching palate
- late/incomplete puberty and infertility
How is Turner syndrome managed?
- growth hormone therapy
- oestrogen and progesterone
- fertility treatment
What conditions are associated with Turner Syndrome?
- coarctation of aorta
- bicuspid aortic valve
- recurrent otitis media
- hypothyroidism
- hypertension
What is Edward syndrome?
- Trisomy 18
What are the features of Edward syndrome?
- low set ears
- small head and jaw
- overlapping 4th and 5th fingers
- rocker bottom feet
- CHD: VSD
What is Patau’s syndrome?
- Trisomy 13
What are the features of Patau syndrome?
- holoprosencephaly: hemispheres don’t fully separate
- microcephaly
- cleft lip and palate
- polydactyly
- CHD: VSD
What is Klinefelter syndrome?
- male has additional X chromosome: 47 XXY
- can be more severe - 48 XXXY or 49 XXXXY
What are the features of Klinefelter syndrome?
- taller height
- wider hips
- gynecomastia
- weaker muscles
- small testicles, reduced libido and infertility
- shyness
What is the management of Klinefelter syndrome?
- testosterone injections
- advanced IVF techniques
- breast reduction surgery
- SALT, OT, physio
What is William syndrome and which chromosome does it affect?
- caused by deletion of genetic material on 1 copy of chromosome 7
- random deletion around conception
What are the features of William syndrome?
- starburst eyes
- sociable, trusting personality
- wide mouth, widely spaced teeth
- mild learning disability
- small chin
- flattened nasal bridge
What conditions are associated with William Syndrome?
- supravalcular aortic stenosis
- hypercalcaemia
- hypertension
- ADHD
What is the management of William syndrome?
- echocardiogram
- BP monitoring
- low calcium diet
What is Noonan syndrome and how is it inherited?
- associated with deletion on chromosome 12
- autosomal dominant
What are the features of Noonan syndrome?
- webbed neck
- short stature
- widely spaced nipples
- hypertelorism: widely spaced eyes
There is an increased risk of which conditions in Klinefelter syndrome?
- breast cancer
- osteoporosis
- diabetes
- anxiety and depression
What conditions are associated with Noonan syndrome?
- pulmonary valve stenosis
- cryptorchidism > infertility
- learning disability
- bleeding disorders
- lymphoedema
What is Prader-Willi syndrome?
- loss of functional genes on proximal arm of chromosome 15 from paternal side
What are features of Prader-Willi syndrome?
- constant insatiable hunger > obesity
- hypotonia
- learning disability
- narrow forehead and almond eyes
- mental health problems
What is the management of Prader-Willi syndrome?
- dieticians > limit access to food
- growth hormone
- physio, OT, psychologist
What is Angelman syndrome?
- loss of function of maternal UBE3A gene
- caused by maternal deletion on chromosome 15 or inheritance of both from father
What are features of Angelman syndrome?
- fascination with water
- happy demeanour
- widely spaced mouth and teeth
- learning disability
- speech development delay
- ataxia
How is Angelman syndrome managed?
- parental education
- social services
- physio and OT
- CAMHS
- anti-epileptic meds if required
What is the difference between Angelman and Prader-Willi?
- both have gene deletion on chromosome 15
- Angelman: if maternal
- Prader-Willi: if paternal
What is fragile X syndrome?
- caused by mutation in FMR1 gene on X chromosome
- coding for fragile X mental retardation protein
Who does fragile X syndrome affect?
- X-linked
- trinucleotide repeat
- males always affected but females vary
What are the features of fragile X syndrome?
- intellectual disability
- long, narrow face
- large ears
- hypermobile joints
- ADHD/autism
- seizures
