Dysmorphology & Gentic/Chromosomal Abnormalities Flashcards
What chromosomal abnormalities cause disease
Copy number variation
Translocation
Additional: Trisomy
How do you assess dysmorphology?
Face: eyes, nose, ears, mouth, chin, philtrum Head shape, size, fontanelles Limbs, feet, hands: Length, nails, palmar/plantar creases, extra digits, fused digits Trunk: Chest shape, nipples Genitalia: Hypospadias Back: Scoliosis Skin: Birthmarks, skin conditions Posture: Hyper/hypotonic Vision Hearing Growth, weight & height Behaviour Communication Pregnancy Hx: Antiepileptics, folic acid
Dysmorphology of the eyes?
Deep set Cyclopia Spacing: Hypertelorism (wide set) Proptosis (bulging) Telecanthi Epicanthic folds Upslanting/downslanting Palpebral fissures
Dysmorphology of the ears?
Position: Normal in line with eyes Rotation Shape Tags, pits Creases
Dysmorphology of the nose?
Shape: long/short Nasal bridge Nares Tip: Bulbous Philtrum: Length, smooth (fetal OH- syndrome)
Dysmorphology of the mouth?
Small/large Lips: Thin/full/cleft Tongue: Large/small Palate: Cleft Uvula Frenulum Gums: Thickened Teeth: Shape, size
Dysmorphology of the chin?
Micrognathia (Small)
What are the signs & symptoms of Down’s?
Hypotonia Small low ears Upslanting eyes Prominent epicanthic folds Protruding tongue Brachycephaly: Flattened back of skull Brachydactyly: Short digits Single palmar crease Sandle gap Brushfield spots on iris Learning disability: IQ 25-70- most common cause of learning disability
What conditions are associated with Down’s?
Heart: ASD, VSD, ToF Hirschprungs Duodenal atresia Hip dysplasia Eczema Deafness Cataracts Leukaemia Alzheimers Subfertility Hypothyroid (annual TFTs)
What are the genetic causes of Down’s?
95% Trisomy 21 (non-dysfunction in maternal oogenesis)
2% Robertsonian translocation
2% Mosaicism
What is the prognosis related to Down’s?
Life expectancy 50-60
Women w/Down’s 50% chance of passing to offspring
What is the pathophysiology of Turner’s Syndrome?
Karyotype XO
Inc FSH- gonadal failure
Most common gonadal dysgenesis in females
What are the signs & symptoms of Tuner’s Syndrome?
Inc carrying angle Flat, wide chest Prominent neck Hyperpigmentation Aortic Coarctation Short stature Rx ear infections (Otitis Media)
What are the characteristics of a child with Foetal Alcohol Syndrome?
Low nasal bridge Epicanthal folds Thin upper lip Flat mid face & short nose Short palpebral fissure Minor ear abnormalities Indistinct philtrum Micrognathia
What are the 3 main features of foetal alcohol syndrome?
– Growth retardation – Characteristic facial features – CNS abnormalities/dysfunction 25 - 30% of people with FAS have an learning disability
