SHANK3 délétion syndrome
Autism
Gene mutation causes reduction in neuro communication
What is Rett’s syndrome?
X-linked DOMINANT in GIRLS. MECP2 gene Deceleration in head circumference Learning disability stereotyped hand movements Psychomotor regressions excessive somnolence/ sleep difficulties
What is phenylketonuria
metabolic disorder of autosomal recessive inheritance
mild learning difficulties and special dietary requirements
- caused by mutations of phenylalanine hydroxylase
What is Turner’s syndrome?
45X0
low hairline, retrognathism short stature, broad chest, webbed neck
Mostly due to loss of PATERNAL X chromosome - aneuploidy (80%)
10 points lower IQ than general population
What does presenilin-1 gene (on chromosome 14) mutations cause?
Early onset Alzheimers disease
What is prader-willi syndrome?
PATERNALLY inherited deletion of 15q11-13 (genomic imprinting)
- affects boys and girls
- obesity
- short stature
- small limbs
- decreased IQ
- hyperphagia
- skin picking
What is Angelman syndrome?
MATERNALLY inherited deletion of 15q11-13 (genomic imprinting) “uniparental disomy, parent of origin effect”
- developmental delay
- low IQ
- jerky movements especially hand-flapping
- frequent smiling
- seizures
- flattened occiput, prominent jaw, wide mouth, pointed chin
What is DiGeorge syndrome?
Also called velocardiofacial syndrome
22q11. 2 autosomal dominant condition, due to deletion
- 25% chance of schizophrenia with this deletion
- mild-mod learning disability
- facial deformities: cleft palate
- absent or malformed paraythyroids -> HYPOcalcaemia
- broad nasal bridge
- articulatory speech and swallowing problems
What is Kallman syndrome?
Different inheritance patterns including X-linked recessive, AD, AR
- hypogonadotrophic hypogoadism
- anosmia
- occasional LD
a/w KISS1 mutation in small number of cases
What is 95% of the genetic cause of Down’s syndrome?
Meiotic nondisjunction of the homolygous chromosome
What is Edwards syndrome?
Trisomy 18 F>M
- severe mental retardation
- ROCKER bottom feet
- low set ears
- micrognathia (small jaw)
- congenital heart disease
- clenched fists
- prominent occiput
What is Patau’s syndrome?
Trisomy 13
- severe mental retardation
- micropthalmia
- microcephaly
- CLEFT LIP/palate
- coloboma eye
- POLYCADACTYLY
- congenital heart disease
What is William syndrome?
7q11 MICRODELETION
- elfin features
- hypercalcaemia at birth
- supravalvular aortic stenosis
- moderate learning disability
- superficially fluent speech
- hyperacusis
What is cri-du-chat syndrome?
Deletion of chromosome 5q
- feeding problems due to difficulty swallowing and sucking
- cat like cry
- poorly developed facial features
What is tuberous sclerosis?
auto DOMINANT 9q34/16p13
- adenoma sebaceum
- normal to severe MR
- ash leaf macules
- brain hamartomas
- heart and kidney cysts
What is Treacher Collins syndrome?
Auto DOMINANT 5q31
maxilla-mandibular hypoplasia
malformed pinna
down slanting palpebrae
What is Noonan syndrome?
Auto DOMINANT Chr 12
- short stature
- nuchal oedema/ webbed neck
- PULMONARY STENOSIS
- cryptorchidism
What is Lesch-Nyhan syndrome?
X-linked RECESSIVE Xq 26-27
- deficiency of enzyme HGPRT
- poor muscle control, moderate mental retardation,
- self mutilating behaviour - lip and finger biting
- Hyperuricaemia and hyperuricosuria -> severe gout and kidney problems
What is fragile -X syndrome?
x-linked AUTOSOMAL DOMINANT!
X-linked trinucleotide expansion
frag(g)ile X- cGG expansion proximal to FMR1
causes:
- mental retardation - most common inherited cause
- most common single gene cause of Autism
- enlarged testes
- prominent ear lobes
- protracting jaw
- high pitched voice
- highly associated with anxiety/depression
What is the inheritance of Huntingtons?
Autosomal dominant trinucleotide expansion at 4q13
hungtingon ChoreA - CAg
What is the inheritance of myoTonic dysTrophy?
Trinucleotide expansion of cTg
What is Klinefelter’s?
XXY
larger body, small testicles, bigger breasts, weaker bones, delayed puberty
What is Cornelia de Lange syndrome?
- Rare
- lack of pregnancy associated plasma protein (PAPPA) on 9q33
- severe profound ID and hypertrichosis
