18. Paediatric Genetics Flashcards
What are the Features of Down Syndrome?
- Trisomy 21 - Congenital (Genetic +/- Environment)
- Learning Disability
- Congenital Heart Disease
- Hypothyroidism
- Immunity
- Early onset Alzheimer’s Disease
What is the Breakdown of the Multiple Congenital Anomaly Syndromes?
- Single Gene Disorders - 30%
- Chromosomal Disorders - 10%
- Teratogens - 5%
- Unknown - 55%
Note - Individually Rare, Common as a Group
What is included in the Description of the Dysmorphic Child?
- Position and Shape of Facial Features
- Hands
- Growth of Child
- General Features
What is included in the Description Position and Shape of Facial Features of the Dysmorphic Child?
- Head:
- a) Shape
- b) Size - Macro/Microcephaly)
- c) Ear Position
- Eyes:
- a) Hypertelorism - Inner Canthal Distance (ICD) and Inter-Pupillary Distance (IPD) Increase
- b) Telecanthus / Epicanthic Folds - Inner Canthal Distance (ICD) and Inter-Pupillary Distance (IPD) Increase
What is included in the Description Hands of the Dysmorphic Child?
- Finger Length
- Digital Abnormalities
- Palmar Creases
Examples - Marfan Syndrome / Down Syndrome
What are the 2 Types of Malformation?
- Alone - e.g. Polysyndactylty - HOX D13 One Cause
2. Part of a Syndrome - Acrocephalopolysyndatyly - Greig / GLI3
What are the Features of a Sequence?
An Abnormality lead to another, can have Many Causes:
- Pierre-Robin Sequence - Small Chin to Cleft Pallate
- Foetal Akinesia Sequence:
- a) Reduced Foetal Movement
- b) Reduced Breathing
- c) Contractures
- d) Clefting
- e) Lung Hypoplasia
What is the Difference between:
- Deformation?
- Disruption?
Both are a Pattern of Development, which was Normal to Start with, but then Becomes Abnormal:
- Deformation - Organ Parts are there
- Disruption - Parts of Organ / Body Part Absent
What is Association?
2+ Features which occur together more often than expected by chance - Mechanism Unclear - VATER: V - Vertebral Anomalies A - Ano-Rectal Atresia T - Tracheo- E - (O)esophageal Fistula R - Radial Anomalies
What is a Syndrome?
A distinct group of symptoms & signs which, associated together, form a characteristic clinical picture or entity
Note - Cause May / May Not be Known
What are the Features of Turner Syndrome (45X)?
- Lymphoedema - Puffy Feet / Nuchal Translucency)
- Short Stature
- Coarctation of the Aorta / Hypertension
- Hypothyroidism
- Osteoporosis
- Increased Carrying Angle / Low Hairline
- Primary Amenorrhoea / Infertility
- Hormonal Therapy mitigates some Factors
What are the Features of Acrocephalopolysyndactyly?
- Tall Forehead
- Polydactyly - Supernumeracy of Fingers / Toes
- Syndactyly - Digits Fused Together
What are the Genetic Investigations of Learning Disability?
- Microarray
- Fragile X
- Targeted Tests driven by Phenotype
