Genetics Flashcards
What is congenital
Present at birth
What are the major mechanisms of congenital malformation
Single gene = 30%
Chromosomal
Teratogens
Environment / unknown = 55%
What is a syndrome
Pattern of clinical features occurring together which form a characteristic clinical picture
What is a sequence
One abnormality leading to another
Multiple causes
What is an association
Two features or more occurring together more often than by chance
What is a malformation
Can occur alone or part of a syndrome
What is a deformation / disruption
Pattern of development normal to start with but becomes abnormal
Organ parts still there
Disruption = organ parts absent
How do you Dx learning difficulty or malformation syndrome
History Recognition of pattern Karyotype - chromosome structure Microarray = standard Targetted tests - fragile X Exome / genome
What is acrocephalosyndactylyl
Syndactylyl - united
Polysyndactyl - extra digit
Craniosynostosis - tall head
What is Pierre-Robin sequence
Small jaw - micrognathia
Tongue obstruction
Cleft palate
= Respiratory distress
What is fetal akinesia sequence
Reduced fetal movement IUGR Contractures / abnormal position Clefting / facial anomaly Pulmonary hypoplasia
What is VATER association
Vertebral anomalie
Ano rectal atresia
Tracheal Eosophageal fistula
Radial anomalies
How do you describe head features
Shape
Macrocephaly
Microcephaly
How do you describe ear position
Low set
Posteriorly rotated - immature
What is hypertelorism of orbit
Inner cantonal distance (ICD)
Inter-pupillary distance (IPD) increased
What is telecanthu
ICD increased
IPD normal
What is epicanthic folds
Fold in inner corner of eye
Important in Downs
How do you describe the hands
Finger length
Digital abnormality
Palmar creases
What occurs in the hands in marfans
Increased finger length
What is Klinefelter’s syndrome
45 XXY
What is Down’s and how do you Dx
Trisomy 21
Antenatal
- Ante-natal screen
- Anti-natal test if high risk
- Non-invasive pre-natal replacing anti-natal as single blood test from mother
Birth
- Karyotype
What are the clinical dysmorphic features of Trisomy 21
Microcephaly + flat occiput Hypotonia Short neck Short stature Round face Epicanthic folds Upslanted palpebral fissue Single palmar crease
Brushfield spot Flat nasal bride Protrudng tongue Small low set ears x Third fontanelle Short stubby fingers Saddle toe deformity
What conditions are associated with trisomy 21
Epilepsy Alzheimers Hypothyroid Cardiac - AVSD, PDA, tetralogy GI - Duodenal atresia Hirschprung ALL Infertility Eye - cataract / myopia Deafness - conductive due to eustachian dysfunction Recurrent otitis media Learning difficulties Atlantoaxial instability - screen if sporty
How do you manage and follow up
MDT
- OT
- SALT
- Physio
- Paediatrician
- Dietician
- GP and HV
- Cardio, ENT, audiologist, optician
- Social services
- Additional support
Regular thyroid
ECHO for cardiac
Regular audiometry and eye check
William Syndrome
Short stature LD Hyperglycaemia Hypercalcaemia Supravalvular AS / hypertension Mitrar regugitation Starburst eyes - pattern on iris Friendly, extrovert Wide spaced mouth with big smile Rx = ECHO, BP monitoring
Rett’s
X-linked Autism GDD Gross motor Microcephaly Seizures Dysmorphism
Prader-Willi and how do you Rx
Hypotonia Hypogonadism Obesity due to constant hunger LD Rx = GH, MDT, lock food
Patau
13 Micrcephalia Cleft lip Polydactly Scalp issue VSD / ASD LD
Edward
Trisomy 18 Micrognathia Low set ears Overlapping finger Rocker bottom feet VSD / PDA
Noonan
AD Webbed neck Pectus evactum Short stature Cryptochordism Ptosis Coagulation issues Pulmonary stenosis
Most common cause of development delay and how is it inherited
Fragile X
X-linked
How does it present
LD, ADHD, autism Speech and language delay Large low set ears Thin long face Hypotonia Macro-orchidism - big testicles Macrocephaly Mitral valve prolapse Seizures
How do you Dx
Chronic villi
Amniocentesis
Achondropalsia
AD in FGFR3 gene Abnormal cartilage Short stature usually limbs Short finger Macrocephaly Frontal bossing MIdface hypoplasia Flat nose Triden hands Lumbar lordosis Otitis media Obesity, OSA Spinal stenosis leading to cord compression
How do you Rx
Limb lengthening
X-linked restive genes
Female = carrier
Male can’t get from dad as he will always give Y
What causes microcephaly
Normal Genetic Congenital HIE / brain injury FAS Syndromes Craniocyntosis
What is Turner’s
Female has a single X chromosome so 45X
Affects female
Can develop X-linked conditions
What are features
Short stature Webbed neck Widely spaced nipple Low set ears Late or incomplete puberty Most are infertile
What is associated
Co-arctation of aorta Aortic stenosis Hypothyroid Obesity Hypertension Osteoporosis DM LD Horseshoe kidney Autoimmune - chron's / thyroid Pectus deformity
How do you Rx
GH therapy
Oestrogen and progesterone for 2 characteristic
Fertility Rx
What is DiGeorge
Chromosome 22 - CATCH 22
- Cardiac
- Abnormal face / Autoimmune - JIA/. ITP / anaemia
- Thymic hypoplasia
- Cleft palate
- HypoCaclium / Hypoparathyroid
Other
LD
Schizophrenia