Developmental disorders Flashcards
Most common form of Down syndrome
Complete trisomy 21
Two more uncommon forms of Down syndrome
Translocation Down syndrome
Mosaic Down syndrome
Percentage of Down syndrome caused by full trisomy 21
95%
Percentage of Down syndrome caused by translocation
2-3%
Percentage of Down syndrome caused by mosaicism
2-3%
Risk of Down syndrome with a maternal age of 35
1 in 385
Risk of Down syndrome with maternal age of 40
1 in 106
Risk of Down syndrome with maternal age 45
1 in 30
Type of Down syndrome which is inherited
Translocation
Type of Down syndrome which occurs as a random event during early foetal development
Mosaic
Type of Down syndrome caused by non-disjunction, with the extra chromosome coming most often from the mother but also can be from the father
Full trisomy
Typical facial features of Down syndrome
Small mouth and protruding tongue Flat occiput Small low-set ears Upward slanting eyes Epicanthic folds Small, flat nose
Non-facial physical features of Down syndrome
Single palmar crease Sandal gap between toes Hypotonia Low birth weight Short stature Overweight as an adult
Most common cardiac defect associated with Down syndrome
AVSD
Medical comorbidities associated with Down syndrome
Visual problems Ear infections Leukaemia Obesity Underactive thyroid Diabetes Reduced fertility Early onset Dementia Oesophageal atresia Hirschsprung's disease
Tests used to assess for dementia in patients with Down syndrome
DMR (Dementia questionnaire for persons with mental retardation)
DSDS (Dementia scale for Down Syndrome)
Condition usually seen in adolescent boys characterised by increased need for sleep, tendency to eat any food available and emotional and behavioural problems
Kleine-Levin syndrome
Usual timing of symptoms in Kleine-Levin syndrome
Abrupt onset
Symptoms remain for a few days
Abrupt disappearance
Repeated episodes like this that can last years, often with a gradual decrease in severity
Condition characterised by neurological and behavioural difficulties in conjunction with overproduction of uric acid
Lesch-Nyan syndrome
Most distinctive behavioural problem associated with Lesch-Nyan syndrome
Self-injury including biting
Gene responsible for Lesch-Nyan syndrome
HPRT1
Enzyme deficiency seen in Lesch-Nyan syndrome
Hypoxanthine phosphoribosyltransferase 1
Sex almost exclusively affected by Rett syndrome
Females
Gene responsible for Rett syndrome
MECP2 gene
Age at which children with Rett syndrome stop developing at a normal rate
6-18 months
Common features of Rett syndrome
Loss of language skills Seizures Stereotypic movements e.g. hand wringing Microcephaly Breathing problems Loss of motor function
Risk of Turner syndrome in siblings of those with Turner syndrome
Unchanged from baseline risk
Features of Turner syndrome
Short stature Webbed neck Broad chest Infertility (usually but not always) Congenital heart disease Hypothyroidism
