Genetics Flashcards by Eilidh Seaton

What is congenital

Present at birth

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What are the major mechanisms of congenital malformation

Single gene = 30%
Chromosomal
Teratogens
Environment / unknown = 55%

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What is a syndrome

Pattern of clinical features occurring together which form a characteristic clinical picture

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What is a sequence

One abnormality leading to another

Multiple causes

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What is an association

Two features or more occurring together more often than by chance

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What is a malformation

Can occur alone or part of a syndrome

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What is a deformation / disruption

Pattern of development normal to start with but becomes abnormal
Organ parts still there
Disruption = organ parts absent

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How do you Dx learning difficulty or malformation syndrome

History
Recognition of pattern
Karyotype -  chromosome structure
Microarray = standard
Targetted tests - fragile X 
Exome / genome

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What is acrocephalosyndactylyl

Syndactylyl - united
Polysyndactyl - extra digit
Craniosynostosis - tall head

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What is Pierre-Robin sequence

Small jaw - micrognathia
Tongue obstruction
Cleft palate
= Respiratory distress

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What is fetal akinesia sequence

Reduced fetal movement
IUGR 
Contractures / abnormal position
Clefting / facial anomaly 
Pulmonary hypoplasia

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What is VATER association

Vertebral anomalie
Ano rectal atresia
Tracheal Eosophageal fistula
Radial anomalies

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How do you describe head features

Shape
Macrocephaly
Microcephaly

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How do you describe ear position

Low set

Posteriorly rotated - immature

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What is hypertelorism of orbit

Inner cantonal distance (ICD)

Inter-pupillary distance (IPD) increased

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What is telecanthu

ICD increased

IPD normal

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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