Genetics Flashcards
Pleiotropy meaning
Genes that gave more than one discernible effect on the phenotype for example CFTR, Marfans, osteogenesis imperfecta
Alpert syndrome gene and inheritance pattern
FGFR2 (fibroblast growth factor receptor 2) AD
Two examples of micro deletions
22q11 and Williams
X linked dominant disorder
Incontinetia pigmenti
Other x linked recessive fragile x on FMR1 gene, haemophilia, duchenne and Becker
Autosomal dominant - name five
Noonan Charge Alagille NF 1 Marfan Ehlers danlos Stickler Achondroplasia Myotonic dystrophy TS Cornelia de Lange
Limit of microarray
Misses balanced translocation
CHARGE
Coloboma Heart Atresia of choanae Retardation growth or mentation Genital abnormalities Ear abnormalities
CHD7 gene
Ddx kabuki and retinoic embropathy
Heteroplasmy
The presence of both normal and mutation carrying mitochondrial DNA in a cell
Aneuploidy caused by
Failure of homologous chromosomes to separate in anaphase I, failure of sister chromatids to separate at meiosis II
Alagille inheritance
AD but 70% de novo (JAG1 gene chr 20p12)
<1% NOTCH2
Ataxia telangiectasia clinically
Ataxia
Telangiectasia
Dev delay
Immunodeficiency
Wiskott Aldrich clinically
Symptoms:
Petechiae (microthrombocytopenia)
Eczema
Immunodeficiency - Chronic draining ears (sinopulm infections)
Ix:
low immunoglobulin M (IgM) and immunoglobulin G (IgG) levels, normal-to-high immunoglobulin A (IgA) and immunoglobulin E (IgE) levels
No response to vaccine
Gene test WAS gene making WAS protein or WASP
XL (male 1-10 per million males)
Badder-biedl
AR variable Short and fat Retinitis pigmentosa Polydactyly Hypogonadism ID
Beckwith-wiedemann
Disorder of imprinted gene 11p15 Overexpression IGF2 Overgrowth, organomegally, omphalocoele Hypoglycaemia Ear crease and pits Tumours
Cornelia de lange
IUgR Mono brow Severe ID Limb abnormalities Cardiac Gut malrotation Self harm behaviour
Most common thing associated 15% downs
Coeliac
Can have transient myeloprolif at birth (normalises by 2m)
Noonan syndrome clinically
PS (ASD, HOCM)
Short
Web neck and triangular face, Epicanthus with slanted eyes, ptosis, low set ear, mild low IQ
Small testes and delayed puberty
Stickler and Marshall due to..
Type 2 collages defect
Smith lemil opitz due to
Defect in cholesterol metabolism elevated 7-dehydrocholesterol AR DHCR7 gene Microcephalic, ambiguous genitalia males Micrognathia Anteverted nostrils Adrenal insuf Syndactyly Severe ID Tx: cholesterol
VACTERAL
Vertebral Anal atresia Cardiac TOF EA Renal Limb
Velocardiofacial (22q11)
22q11 deletion (TBX1 and COMT)
1/4000
Sporadic (7% inherited AD)
Cleft palate with bifid uvula
VSD, conotruncal, commonly interrupted aortic arch B
Long face hypotonic with bulbous tip broad nose
Williams
AD, 20 gene deletion on chr 7
FiSH (microdeletion)
Prominent lips, fat around eyes, big ears, blue eyes, stellate pattern on iris, elfin facies hypercalcaemia in infancy (resolves)
cocktail personality
Short stature and FTT
Cardiac abnormalities
– Supravalvar aortic stenosis 50%
–Peripheral pulmonary stenosis 27%
Intellectual disability ~100%
anxiety
Zellweger
Peroxisomal disorder Hypotonia Absent reflexes Hearing and visual loss Seizures High forehead, large fontanell Hepatomegally Die infancy no Rx
Aneuploidy
Wrong no. Chromosomes