Genetic disorders in children Flashcards
How many children in the UK are born with a genetic defect and by what percentage is hospital stay increased?
1 in 25
40%
How might a child with genetic defects present?
Dysmorphic features
Multiple anomalies
Developmental delay/learning difficulties
A disease that recurs in the family
List some dysmorphic features that might affect the hands and feet
Polydactyly
Rocker bottom feet
What skin sign is often seen in genetic conditions?
Cafe au Lait spots
What dysmorphic features may affect the face?
Low set ears
Down slanting eyes with prominent epicanthal folds
Micrognathia and or retrognathia
By how much is the incidence of genetic disorders increased in consanguineous children
twice as high
What are the causes of anomalies present at birth
Infections
Drugs (prescribed or illicit)
Birth/pregnancy complications
Genetic disorders
What is Karyotype testing
Testing for chromosomal abnormalities, with a resolution of 30-40 genes
What does FISH stand for
Fluorescent In-Situ Hybridisation
What does QF-PCR stand for
Qualitative Fluorescent Polymerase Chain Reaction
What is FISH used for
FISH is a targeted method that uses probes to specific regions of genes
Used for common aneuploidies
What is QF-PCR used for
Amplifies specific regions of DNA, only used for common aneuplodies. It is rapid, specific and accurate
What method is an example of microarray genetic testing
Comparative genomic hybridisation (CGH)
What is the resolution of microarray testing
Single gene
What does microarray testing do
Looks at the amount of material present (so cannot detect balanced translocations). Much more sensitive than karyotype, FISH or QF-PCR and detects 3x as many abnormalities
What is next generation sequencing
Identifies the order of bases at a single base resolution
What condition results from T21
Down syndrome
What characteristics at birth can be identified in a down syndrome child
Hypotonic Single palmar crease Wide sandal gap (between 1st and second toe) Down slanting eyes Prominent epicanthal folds
_____ is the commonest
genetic cause of learning difficulties
Down Syndrome
Cardiac anomalies are present in __% of Down syndrome babies and the most common is ____
50%
Atrioventricular septal defect
What condition is caused by an absent or partially absent X chromosome
Turner syndrome
Turner Syndrome babies usually survive to birth (T/F)
False
What are some clinical features of Turner Syndrome
Short Stature Webbing of the neck Widely spaced nipples Congenital heart defects Infertility
What is the most common heart defect in Turner syndrome children
Coarctation of the aorta
What condition is caused by T18
Edwards Syndrome
What condition is caused by T13
Patau syndrome
Most children with Edwards Syndrome die in infancy (T/F)
True
Most children with Patau syndrome die in infancy (T/F)
True
What are some clinical signs of Edwards syndrome
Low birth weight Micrognathia Fixed overlapping fingers Rocker bottom feet Often cardiac and renal problems
What are some clinical signs of Patau syndrome
Cleft lip and palate
Polydactyly
Small eyes
Often abnormalities of the brain, heart and kidneys
