Paediatric genetics Flashcards
What are the features of Prader Willi syndrome?
What is the mode of inheritance?
How is it managed?
Hypotonia, developmental delay and hyperphagia, blue eyes blonde hair
deletion in chromosome 15 (imprinting - usually paternal)
Growth hormone, Olanzapine, fluoxetine (food)
What are the features of Angelmans syndrome?
Presents at aged 3-7. - developmental delay - minimal / no words - HAPPY / EXCITABLE - laughter to most stimuli - Hand flapping + broad gait Other: - microcephaly - seizures - drooling - fascination with water
What is the mode of inheritance for Angelmans syndrome?
Maternal deletion on chromosome 15 (opposite to prader willi)
What is the genetics of turner syndrome?
Loss or abnormality of the second X chromsome in at least one cell line.
40-60% = 45X0 monosomy
What are the features of Turner syndrome?
newborn - lymphoedema hands + feet, cardiac/renal abnormalities
Infancy - short stature, webbed neck, recurrent otitis media, bicuspid aortic valve/ CoA
Adolescence - gonadal dysgenesis! ALMOST ALL ARE INFERTILE
Also associated with autoimmune diseases
How is Turner syndrome managed?
Growth hormone
Treat complications
Oestrogen at 12 yrs - initiates puberty and prevents osteoporosis
What are the features of Noonan’s syndrome?
Face - big forehead, wide set eyes, ptosis and down slanting eyes, low set ears, striking blue/green eyes + curly hair
- short, webbed neck
- broad chest
- cardiac problems
- learning disability
- bleeding disorders
What is the inheritance of Noonan syndrome?
Autosomal dominant (relatively common)
What is neurofibromatosis and what is the genetic inheritance?
Genetic disorder causing lesions in skin, nervous system and skeleton
Autosomal dominant, though 50% have no family history
What are the main differences between type 1 and type 2 neurofibromatosis?
what is Schwannomatosis?
Type 1:
Gene = NF1 at chromosome 17q11.2
Sx = skin lesions (cafe-au-lait, freckling, neurofibromas)
Type 2: CNS tumours
Schwannomatosis = multiple non-cutaneous schwannomas (present with pain)
What is the typical clinical presentation of NF1?
Cafe-au-lait spotd by age 1 - increase in size and number
Freckling in skin folds by age 10
Neurofibromas at puberty
Lisch nodules - brown mounds ono iris at age 6
Short stature + macrocephaly
- mild learning difficulties, increased risk of malignancy, local affects of neurofibromas
What is the typical clinical presentation of NF2?
Schwannomas of multiple cranial and spinal nerves
- mainly vestibular nerve (bilateral)
- Sensineural hearing loss = 1st sign
- Other tumours such as meningiomas + ependyomas
- less cafe-au lait spots
How is neurofibromatosis diagnosed?
X-ray - bone defects
MRI head
>6 cafe-au lait spots + FHx + clinical examination
defects in NF gene
What is the genetics of fragile X (Martin-Bell) syndrome?
How does it present?
X-linked, semi dominant TRINUCLEOTIDE REPEAT (CGG) on Xq27 - lengthens through generations.
- Delated speech / motor
- Learning difficulties
- Autism
- Physical = long, narrow face, large ears, prominent jaw, big testes
What is the genetic inheritance of Klinefelter syndrome?
What is the presentation and the management?
46 XXY (males with an extra X chromosome)
- Male hypogonadism
- Gynaecomastia
- Infertility
Management - androgen therapy
What are the key features of Edward’s syndrome (trisomy 18)?
Micrognathia (small lower jaw)
Low set ears
Rocker bottom feet
OVERLAPPING FINGERS
What are the key features of Patau syndrom (trisomy 13)?
Microcephaly SMall eyes Clift palate/lip Polydactyly Scalp lesions
What is the genetic inheritane of Downs syndrome?
Trisomy 21
In most cases the extra copy is maternal - error in cell division = non-disjunction
Less common = translocation
What are some common features of Down’s syndrome?
Face - epicanthic folds, protruding tongue, small loow seet ears, high arched palate
Cardio - CHD
ENT - hearing loss common
Vision problems
Ortho - single palmar crease, hip dysplasia, foot atlanta-axial instability
Endo - hypothyroidism
Neuro - learning difficulties, seizures, dementia
What are the key features of William’s syndrome?
Short stature Learning difficulties Extrovert personality Transient neonatal hypercalcaemia Supraventricular aortic stenosis
