Genetics and Dysmorphology Flashcards
22q11.2 deletion
What is it also known as
(aka: DiGeorge, velocardiofacial syndrome)
HYPOCALCEMIA, IMMUNE DEFICIENCY, KIDNEY abnormalities
hearing loss
congenital heart disease, palatal abnormalities
characteristic facial geatures, learning problems
Dx by fluorescence in situ hybridization analysis for submicroscopic deletion of chromosome 22, high-res karyotype, or chromosomal microarray
branchio-oto-renal syndrome (BOR)
mutations of EYA1 and SIX1
deafness
external ear deformities
lateral semicircular canal hypoplasia
brachial arch anomalies
renal malformations
Treacher Collins Syndrome
mandibular and zygomatic hypoplasia
coloboma of lower eyelids, absent lower eyelashes, external ear abnormalities, preauricular hair displacement onto cheekbones
CONDUCTIVE hearing loss (not SNHL)
3 genes: TCOF1, POLR1C, POLRID
Spinal Muscular Atrophy (types, onset, symptoms)
SMA 0: prenatal onset with infantile death
SMA I: onset <6 mo with lifespan >2 years
SMA II: onset 6-18 mo, 70% alive at 25 years of age
SMA III: onset >18 mo, normal lifespan
SMA IV: adulthood onset, normal lifespan
Gene: SMN1 or SMN2 (the more 2, the milder phenotype)
Types of Testing (8)
- Karyotype or 2. microarray: intellectual disability, autism, or multiple congenital anomalies
- Fluorescent in situ
- Hybridization Analysis
- Multigene panel testing
- Whole exome sequencing
- Specific (single) gene mutation analysis
- DNA methylation (Prader WIlli and Angelmann)
Spinal Muscular Atrophy (types, onset, symptoms)
SMA 0: prenatal onset with infantile death
SMA I: onset <6 mo with lifespan >2 years
SMA II: onset 6-18 mo, 70% alive at 25 years of age
SMA III: onset >18 mo, normal lifespan
SMA IV: adulthood onset, normal lifespan
Gene: SMN1 or SMN2 (the more 2, the milder phenotype)
+ tongue fasciculations
Endocrine abnormalities associated with Prader Willi
GH deficiency is universal
(and other HPA dysfunction like central hypothyroidism, OSA)
Prader Willi Syndrome
Characteristics and Dx
Global hypotonia
poor suck
hypogonadism
characteristic facial features (bitemporal narrowing of head, triangular mouth)
Global developmental delay
Behavior: compulsiveness, stubbornness, manipulative
HYPERPHAGIA, but feeding difficulties
Hypoplastic genitalia
SHORT stature
osteoporosis
small hands/feet, poor growth in early childhood
Almond-shaped eyes
Obesity
Dx: DNA methylation testing of parent specific imprinting (PWCR on Chromosome 15), also 2/2 inheriting 2 copies of chromosome 15 from mother
TFTs annual
Zellweger Syndrome
AR
Presentation: newborn period with global hypotonia, poor feeding, seizures, liver cysts w/ dysfunction, distinctive facies (flattened facies, large anterior fontanelle, broad nasal bridge, widely spaced sutures.)
Usually die in 1st year of life
Pancytopenia (what syndrome is it associated with?)
Fanconi Anemia
&
X-linked dyskeratosis congenita
Thrombocytopenia (what syndrome is it associated with?)
Wiskott-Aldrich syndrome
&
Thrombocytopenia absent radius syndrome
Hypercalcemia
Hypercalciuria
HYPOthyroidism
Williams Syndrome (triad)
+ supravalvular aortic stenosis
7q11.23
47,XYY
Expected sexual development/fertility, development, behavioral development, stature
- normal sexual and fertility
- Normal to mild delayed intelligence
- Behavior: impulsivity & hyperactivity
- TALL Stature
47,XYY
Expected sexual development/fertility, development, behavioral development, stature
- normal sexual and fertility
- Normal to v mild delayed intelligence
- learning/speech delay - Behavior: impulsivity & hyperactivity
- TALL Stature
- Bonus: cystic acne as adolescence
47,XXX
Expected sexual development/fertility, development, behavioral development, stature
triple X syndrome
TALL Stature (females)
Learning disabilities: usually normal (learning/speech)
Can have 10% seizures + kidney anomalies
Trisomy 13
microcephaly
microphthalmia
low-set ears
cleft lip and/or ppalate
holoprosencephaly
cutis aplasia (absence of skin)
polydactyly
clenched hands
cryptorchidism
renal anomalies
cardiac malformations
Trisomy 13
Patau Syndrome (1/16,000)
specific to trisomy 13:
cleft lip and/or palate
holoprosencephaly
cutis aplasia (absence of skin)
MIDLINE DEFECTS, HYPOTONIA, MICROPHTHALMIA (vs. tri 18)
others:
microcephaly
low-set ears
polydactyly
clenched hands
cryptorchidism
renal anomalies
cardiac malformations
Trisomy 18
features and how is it different/ similar to trisomy 13
Edwards Syndrome (1/5000)
Different: hypertonia, clenched fists, rocker-bottom feet, myomeningocele
Similarities to trisomy 13:
characteristic facial dysmorphology, prenatal and postnatal growth deficiency, renal and cardiac anomalies, severe intellectual disability, and nuchal thickening.
Dolichocephaly, external ear anomalies, micrognathia, short palpebral fissures, and small face.
5-10% of affected infants survive beyond the first year.
Non-inherited
NF2 eye exam findings
subcapsular lens opacity (rarely will progress to cataract)
NF1 eye exam findings
iris lisch nodules
colobomas are associated with ____
CHARGE
Heterochromia iridis is associated with ____ (4)
- Waardenburg syndrome
- Sturge-Weber Syndrome
- Parry-Romberg syndrome
- Horner syndrome
Shwachman-Diamond Syndrome
Exocrine Pancreatic Insufficiency (low elastase level), neutropenia, bone deformity, short stature, multiple infections
AR
If both parents have 1 copy of autosomal recessive trait, what’s the risk of kids getting the disease
25%
Which 3 diseases are X-linked dominant
- Incontinentia pigmenti
- Rett Syndrome
- Fragile X syndrome
MELAS
Mitochondrial Encephalomyopathy
Lactic Acidosis
Stroke-like episodes
- mitochondrial pattern of inheritence
Leigh Syndrome mode of inheritance
mitochondrial and AR inheritance
Uniparental disomy (UPD)
- what is it
- what syndromes are inherited this way
Patient inherits 2 copies from one parent’s chromosome (one parent’s is missing)
- Prader-Willi
- Angelman
- Beckwith-Wiedemann
Mode of inheritance for Friedreich Ataxia, Huntington, Fragile X
trinucleotide repeat expansion
Trisomy 21 physical presentation (7 systems)
- Face: epicanthal folds with up-slanting palpebral fissures, brushfield spots of iris, flat nasal bridge
- Neurologic: hypotonia
- Cardiovascular: conotruncal defects, AV canal defects
- GI: duodenal atresia, tracheoesophageal fistula, Hirschsprung, imperforate anus, Celiac
- Extremities: 5th finger clinodactyly, single transverse palmar creased, sandal gap toes
- Heme: Transent myeloproliferative disorder (10%), Lifetime risk of leukemia 1%
- Other: OSA, Obesity, Hearing loss in adulthood
Preventative health for trisomy 21 (5)
- CBC and TFT 6mo then 1yr and annually
- TTE
- XR cervical spine (if asymptomatic or getting intubated)
- Abd imaging if symptomatic
- Sleep study by 4 yo
Syndromes with craniosynostosis (3)
- Crouzon - (FGFR2)
- Pfeiffer Syndrome - (hearing loss, pollux/hallus varus +/- syndactyly)
- Apert Syndrome (prominent syndactyly, hearing loss)
Common clinical presentation of Crouzon
- Hypertelorism (large space between eyes)
- proptosis
- midface hypoplasia
- Cleft lip/pallate
- Beaked nose
- Prognathism
*normal intelligence and normal extremities)
Syndromes with PUBERTAL phenotypes (5)
- Turner
- Noonan
- Klinefelter
- Fragile X
- Prader-Willi
Turner Syndrome mode of inheritance
monosomy X (45 X)
NOT inherited
NOT associated with advanced materanal age
Noonan Syndrome mode of inheritance
Multiple gene mutations: PTPN11, SOS1, RAF1, RIT1) activation of RAS/MAPK cell signaling pathway (disrupts cell growth and division)
AD inheritance
Features of Noonan syndrome
- facial dysmorphology
- congenital heart defects
- short stature
- developmental delay
47,XXY
Development, stature, pubertal
Klinefelter
TALL stature (males)
Gynecomastia, microorchidism, micropenis, hypospadias
- Delayed puberty – needs testosterone replacement therapy if no spontaneous puberty, but usually normal
- Increased risk of testicular and breast cancer
Development: variable (speech, autism)
Turner sd physical manifestation (4 systems)
- Face: webbed neck, redundant nuchal skin, pos posterior hairline
- CV: shield chest with wide-spaced nipples, congenital heart defects (left-sided bicuspid aortic valve is common, coarctation of aorta)
- Extremities: congenital lymphedema (hands & feet), dysplastic nails, skeletal abnormalities (Short 4th 5th metacarpals, cubitus valgus, scoliosis, congenital hip dislocation)
- Other: short stature, renal abnl
Turner dx and other labs
Karyoptyping (FISH or array)
FSH & LH high, Estradiol Low
TFT
Imaging: TTE, renal bladder, Ophthalmology
Other: audiology
Turner
1. Stature
2. Puberty
3. Fertility
- Short (because of estrogen insufficiency, not because of premature menarchy)
- delayed
- infertile (streaked ovaries with premature ovarian failure)
Turner management/tx
- growth hormone
- Estrogen by 13yo if no spontaneous puberty
- DM (increased risk)
- Surveillance for hypothyroidism, celiac, IBD
Noonan how is it different from Turner
and what else
Down-slanting palpebral fissures
RIGHT-sided CV: pulm vein stenosis, atrial septal defect, hypertrophic cardiolmyopathy
- Face: webbed neck, low-set posteriorly rotated ears, hypertelorism, epicanthal folds, ptsosis, ocular anomalies
- CV: pectus carinatum, wide-spaced nipples
- GU: cryptoorchidism
- Heme: coagulopathy
- Extremities: lymphatic dysplasia, other, short stature
Noonan Dx
Labs: Multigene panel (PTPN11, SOS1, RAF1, RIT1)
CBC ,PT/PTT
Urinalysis
Imaging: TTE, renal US, XR chest/spine, MRI if symptomatic
Studies: ECG, ophtho eval, audiology
Noonan
1. Stature/growth
2. Puberty
3. development
- post-natal growth failure by 1 year of age
- normal puberty
- delays possible
Fragile X inheritance and genetic problem
XL dominant
trinucleotide CGG repeat expansion in FMR 1
<44 repeats = normal
Intermediate 45-54
Premutation 55-200
Full mutation 200+
Most common inherited intellectual disability
Fragile X
Fragile X physical manifestation
- Face: long narrow face, large ears, prominent jaw, tall forehead
- Neuro: Intellectual disability, speech delay, behavioral issues, fragile x- associated tremor ataxia syndrome (FXTAS), strabismus, seizures
- GU: Macroorchidism, extremities, pes planus, female carriers – premature ovarian failure
- CV: mitral valve prolapse
infertile
NF1 Inheritance
Autosomal dominance
Diagnostic criteria for NF1
2+ of the following:
- 6 hyperpigmented cafe-au-lait macules (5 mm in children, 15 mm postpuberty)
- 2+ neurofibromas or plexiform neurofibroma
- axillary or inguinal freckling (often appears in late childhood)
- optic glioma <10 yo
- 2+ lisch nodules (iris hamartomas, <20 years of age)
- Tibial pseudoarthrosis or sphenoid dysplasia
- 1st degree relative with NF1
If you think someone has NF1, what is the imaging and labs to get
- NF1 molecular testing
- MRI for detection and monitoring of internal neurofibromas over time, including signes of cerebrovascular disease
- Unidentified bright objects (UBOs) visualized in 50% of children with NF1
Monitoring and Tx for NF1
TUMORS
Ophtho: dx of optic glioma
Seizure treatment
Tumors: glioma and pheochromocytomas, jeuvenile myelomonocytic leukemia, breast cancer
Routine tumor surveillance
Scoliosis monitoring
Clinical diagnosis of NF2
One or more of the following:
1. Bilateral vestibular schwannomas
2. 1st degree relative with NF2 and unilateral schwanomma, glioma, neurofibroma, posterior subcapsular lenticular opacities
3. Unilateral schwannoma and any two of those listed previously
4. Multiple meningiomas and unilateral schwannoma or any two of the following: schwannoma, glioma, neurofibroma, cataract
Dx of NF2
NF2 molecular genetic testing
MRI/CT head
audiology eval
ophtho