Syndromes Flashcards
Fragile X genetics
trinucleotide repeat CGG in FMR1 region on X-chromosome –> PCR/southern blot looking at the number of repeats
Genetic anticipation
>200 copies = full mutation [5-44 normal, 44-54 grey zone, 55-200 = premutation carrier]
Female carrier frequency est 1:178
Fragile X features
large ears, long face, high arched palate, dental crowding macro-orchadism (post-pubertal) joint hyperlaxity (pes planus) seizure 20% macrocephaly (subtle) MVP <3
Fragile X development outcomes
hyperactivity sensory integration problems intellectual disability (female IQ > male) ASD Enuresis
Fragile X health supervision
Eyes - strabismus, vision ears - recurrent AOM, may need tubes to preserve hearing cardiac - MVP (exam for murmur or click) MSK - joint laxity CNS - seizure risk Development assessment
Fragile X Anticipatory guidance
Genetics referral
psychosocial
support groups
early intervention for PT, OT, SLP as required
Behavious (outburts, sexual issues etc)
Education (preschool, education needs, vocational training)
Fragile X DDx (x-linked [2] or similar features[1])
Usual ones: ADHD, LD, ODD, FASD, ASD
–> X-linked intellectual disability disorders: 1) Lujan-Fryns Syndrome (marfanoid habitus and macroorchidism) and
2) Atkin Syndrome (large ears, macroorchidism, and short stature)
–> Sotos Syndrome (Cerebral Gigantism): Overgrowth syndrome with features of macrocephaly, prominent forehead, prominent chin/mandible, coordination
dysfunction, and usually intellectual disability and difficult behavior.
Prader-Willi genetics
15q11 –> 75% paternal microdeletion
20% maternal uniparental disomy
Absence of the paternally inherited contribution of the PWS region of chromosome 15 leads to lack of the gene products and causes the findings of PWS
Methylation analysis + FISH
Prader-Willi features
Neonate: hypotonia, FTT, poor feeding
Pre-school: hyperphagia, dev delay
Bitemporal narrowing, almond eyes, tapering of digits
Prader-Willi associated medical conditions
Endo: hypothalamic insufficiency –> GH = short stature(eligible for replacement), primary adrenal insuf, hypothyroid
hyperphagia - obesity, OSA, T2DM, dyslipidemia
central sleep apnea
scoliosis (musc hypotonia)
Prader-Willi development outcomes
Gross motor delay (sit at 12 months, walk at 24)
poor coordination
language delay
intellect - IQ 60-70 (strength is visual-spacial, reading, weak in math and sequence processing)
tantrums, ADHD, OCD, psychosis, high pain tolerance
DDx for obesity/intellectual disability
Prader-Willi
Bardet-Biedl Syndrome (polydactyly, retinitis pigmentosa, cystic renal disease)
Cohen Syndrome (hypotonia, prominent central incisors, retinal dystrophy)
Alstrom Syndrome (cone-rod dystrophy, deafness, type 2 diabetes)
Sotos Syndrome
Prader-Willi health supervision newborn
confirm diagnosis
review feeding, hypotonia, need for NG
OSA
hypogonadism
Prader-Willi health supervision infancy
plot growth on growth curve development assessment and early referral vision and hearing (annual) boys - undescended testes dietitian - aggressive weight mgmt assess GH dentist - increased risk of caries OSA - sleep study (esp before GH)
Prader-Willi health supervision childhood
Vision - annual Thyroid q2-3 years or if symptomatic Behaviour (hyperphagia) Growth and development scoliosis Premature adrenarche skin-picking (behavioural) risk of psychosis when older
Angelman syndrome genetics
15q11
Missing maternal!
70% maternal microdeletion
10% UBE3A gene mutation (gene in this area)
5% paternal uniparental disomy (milder phenotype)
10% unknown
rest - imprinting
testing: DNA methylation is most sensitive single test, but DNA sequence analysis required to identify UBE3A mutations. Recurrence risk <1% for microdeletion
and pat. uniparental disomy. Recurrence risk as high as 50% for maternally inherited imprinting center defect or UBE3A mutation. (same as P-W)
Angelman syndrome features
“happy puppet”
psychomotor delay
seizures
acquired microcephaly
GDD
forward bend gait, arms held high bent at elbows
Severe intellectual disability
Good receptive language skills, but generally non-verbal
persistent social smile and bursts of laughter (as early as 10 weeks)
hyperactive
abnormal sleep cycle
Angelman syndrome health supervision
Hearing and vision Adaptive equipment early intervention by multi-D Seizures - AED, neurology involvement family support for hyperactivity and abn sleep cycle
Beckwith-Weidemann genetics
11p15 - dysregulation of imprinted genes
sometimes AD, most spontaneous loss of methylation centre for imprinting. Some paternal uniparental disomy (loss of mom)
Beckwith-Weidemann features at birth (8)
LGA omphalocele or umbilical hernia macroglossia, facial nevus flammeus, post. helical pits, prominent eyes, anterior ear lobe creases HYPOGLYCEMIA + polycythemia
Beckwith-Weidemann medical conditions
Hypoglycemia polycythemia hypocalcemia Dyslipidemia hypothyroid cardiomegaly (rare - HLHS, PFO, mild PS) nephromegaly risk of malignancy (embryonal tumours)
Beckwith-Weidemann malignancy risk and supervision
Wilm’s, hepatoblastoma, neuroblastoma
AUS q3mo until age 8
AFP q6weeks until age 4
22q11.2 Deletion Syndrome Genetics
Usually sporadic mutation from normal parent
AD from affected parent
FISH
22q11.2 Deletion Syndrome features
Cardiac: TOF, VSD, interrupted aortic arch
facial: hypertelorism, long tubular nose, palate anomalies, velopharyngeal insuf
hypoCa! HypoPTH
Thymus aplasia - T-cell immunodef.
30% renal problems
Chronic AOM and sinusitis - with conductive hearing loss > SNHL
eyes: strabismus, posterior embryotoxin
Development: >90% delay, ASD 20%, communication disorder
Increased psych: bipolar, schizo, mood
22q11.2 Deletion Syndrome DDx
Cayler Cardiofacial Syndrome (asymmetric crying facies +conotruncal cardiac malformation): also 22q11.2 deletion
CHARGE Syndrome also features congenital heart disease, immunodeficiency,
hypocalcemia, and hearing loss.
Some overlap with oculo-auriculo-vertebral spectrum
(Goldenhar Syndrome), Kabuki Syndrome, Alagille Syndrome
22q11.2 Deletion Syndrome health supervision (8)
Cardiology evaluation Endocrine evaluation -->Calcium, hypoparathyroid studies Renal ultrasound Developmental evaluation Early referral for Speech Therapy Monitor for Hearing Loss Immunology evaluation
Turner Syndrome Genetics
karyotype - 45XO (majority)
can also have mosaic 45X-/46XX*
*sometimes one of the mosaic X can have a structural defect
Turner Syndrome associated cardiac findings
Bicuspid aortic valve, CoA, HLHS with heart failure
LEFT heart lesions (vs. Noonans)
Turner Syndrome associated renal findings
> 60%
horseshoe kidney, ectopic kidney, aplasia, double collecting system, UPJ obstruction
Turner Syndrome associated ENT findings
chronic AOM, conductive hearing loss