Genetic syndromes Flashcards
What is DiGeorge syndrome?
Primary immunodeficiency disorder causing by T cell deficiency and dysfunction
What are the genetics of DiGeorge syndrome?
Autosomal dominant
22q11.2 deletion (deletion on q arm chromosome 22)
What are the features of DiGeorge syndrome?
CATCH22
Cardiac abnormalities
Abnormal facies
Thymic hypoplasma
Cleft palate
Hypocalcaemia/hypoparathyroidism
Chromosome 22 deletion
What is the main risk factor for Down’s syndrome?
Increasing maternal age
What is a way of remembering the risk for Down’s with maternal age?
1:1000 at 30 then 3x more common every extra 5 years
What is the most common cause of Down’s syndrome?
Nondisjunction
What are the facial clinical features of down’s syndrome?
Epicanthic folds
Small low set ears
Round/flat face
Upslanting palpebral tissues
Brushfield spots in iris
Protruding tongue
What are the clinical features of Down’s syndrome?
Flat occiput
Single palmar crease
“Sandal gap” between biog and 1st toe
Hypotonia
Congenital heart defects
Duodenal atresia
Hirschsprung’s disease
What is the most common cardiac complication in Down’s syndrome?
Endocardial cushion defect - 40%
What are the common cardiac complications in Down’s syndrome?
Endocardial cushion defect - 40%
VSD - 30%
Secundum ASD
Tetralogy of Fallot
PDA
What are later complications of Down’s syndrome?
Subfertility
Learning difficulties
Short stature
Repeated respiratory infections
ALL
Hypothyroid
Alzeheimer’s
Atlantoaxial instability
What is fragile X disorder?
Trinucleotide repeat disorder
What are the common features of fragile X syndrome?
Leaning difficulties
Macrocephaly
Long face
Large ears
Macroorchidism
What is Turner’s syndrome?
45X or 45 XO
Presence of only 1 sex chromosome or deletion of short arm of one of X chromosomes
Who is Tuner’s seen in?
Females only
What are the visible clinical features of Turner’s syndrome?
Short stature
Shield chest, widely spaced nipples
Webbed neck
High arched palate
Short 4th metacarpal
Multiple pigmented naevi
Lymphoedema
What are the clinical features of Turner’s syndrome?
Bicuspid aortic valve, coarctation of aorta
Primary amenorrhoea
Elvated gonadotrophin
Hypothyroid
Horseshoe kidney
What are the genetics Noonan syndrome?
Autosomal dominent
Defect on chromosome 12
What are the common clinical features of Noonan syndrome?
Webbed neck
Pectus excavatum
Short stature
Pulmonary stenosis
What are the internal features of Noonan?
Pulmonary valve stenosis
Factor XI deficiency
What are the genetics of Prader-Willi syndrome?
Absence f Trader-Willi gene of long arm of chromosome 15
Either due to - micro deletion of parental gene
Maternal uniparental disomy of chromosome 15
What are the common features of Prader-Willi syndrome?
Hypotonia
Hypogonadism
Obesity
What are the features of Prader-Willi?
Dysmorphic features
Short stature
Hypogonalism and sub fertility
Learning difficulties
Childhood obesity
Behavioural problems
What is Patau syndrome?
Trisomy 13
