Chromosomal/Genetic Syndromes Flashcards
What disorder is characterized by skin and bone abnormalities resulting from tumors growing along the nerve?
Neurofibromatosis type 1
What characterizes neurofibromatosis type 2?
Bilateral acoustic schwannomas on the 8th cranial nerve, meningiomas, and ependymomas
How is neurofibromatosis type 1 inherited?
- Autosomal dominant genetic disorder
- Gene location: chromosome 17
What are the diagnostic criteria for NF1?
Two or more of the following: 1 )6 or more cafe-au-lait macules 2) 2 or more neurofibromas or 1 plexiform neurofibroma 3) Freckling in the axilla or groin 4) Optic glioma 5) 2 or more Lisch nodules 6) A distinctive bony lesion 7) A first degree relative with NF1
What is the neuropathology of NF1?
- Brain tumors (seen in 15% of people) w/ most present by age 6. Most are optic gliomas (benign)
- T2 hyperintensities (60-70% of those with NF1) in the basal ganglia, cerebellum, thalamus, brainstem, and subcortical white matter
- Macrocephaly/megalencephaly (30-50% of people)
What are the presentation, disease course, and recovery like with NF1?
- Most symptoms worsen over time
- Neurofibromas increase in number during puberty and pregnancy
- But T2H resolve by early adulthood
- Children have delays in development
- There is no recovery; neurocognitive profile remains static
What are the cognitive characteristics of NF1?
- Learning disabilities
- ADHD
- FSIQ ranges from 89-98 (leftward shift)
- Deficits in attention and EF
- Deficits in language, manual dexterity, coordination, and balance
- Verbal and visual mem intact
What are common behavioral characteristics of NF1?
- Internalizing disorders
- Poor impulse control can be associated with ADHD
- Socially awkward
What are the key physical/medical characteristics of tuberous sclerosis complex (TSC)?
- Cortical tubers
- Facial angiofibromas/hypomelanotic macules
- Shagreen pathc
- Subpendymal nodules: hamartomas
- Subpendymal giant cell astrocytoma: slow growing most common brain tumor
- Cardiac rhabdomyoma
- Lymphangiomyomatosis
- Renal angiomyolipoma
- Epilpesy
What are the common cognitive and behavioral characteristics of TSC?
-ID: bimodal distribution (30% have profound ID and 70% normal to superior IQ)
-High rates of LD in those w/ normal IQ
-Deficits in attention and EF
-Only 30% have normal language development
-Deficits in memory recall w/ spared recog
-Autism (40-50% diagnosed with this)
=50% exhibit behavioral problems
How is TSC inherited?
- Variably expressed, autosomally dominant
- From one of 2 genes: TSC1 or TSC2
- Clinical presentation of TSC1 may be milder
What is the morbidity and mortality of TCS?
- 80-90% diagnosed with epilepsy & seizures begin in infancy & typically intractable
- 45% diagnosed with ID
- 40-50% diagnosed with ASD
- 25=50% diagnosed with ADHD (higher prevalence in children with seizures)
- Life expectancy variable
What is the disease course in TSC?
- Variable: those w/ profound ID show little cog progression past the sensorimotor stage
- Infants tend to remain delayed compared to peers over time
- Children w/out early delays fall behind peers during school years
- No intellectual or behavioral regression
What are the major characteristics of Sturge-Weber Syndrome (SWS)?
- Facial capillary malformation or port-wine birthmark (PWB in the region of the ophthalamic division of the trigeminal nerve)
- Vascular malformation of the brain (typically on the same side as the PWB in the occipital and parietal lobes)
- Glaucoma
- Seizures
- Migraines
- Stroke-like episodes: associated with seizures/migraines and present with weakness or sensory disturbance
- 18 fold increase in prevalence of growth hormone deficiency
Is SWS genetic?
It has no known genetic basis and is nonfamilial
What are the cognitive/behavioral characteristics of SWS?
- ID (50-60% diagnosed with ID)
- Varying deficits related to medical complications
What is the neuropathology of SWS?
- Leptomeningeal angioma: capillary-venous vascular malformation of the brain
- PWB increases the risk of brain involvement by 10-20% and is correlated with size
- Cerebral atrophy and cortical calcification: lateralized in the occipital and parietal regions
How many individuals with SWS have unilateral brain involvement?
- 75%
- Of those with bilateral brain involvement, 95% have seizures (contralateral to the PWB)
What group is most susceptible to stroke-like episodes in SWS?
- Toddlers and young children
- These are precipitated by falls typically
Describe the seizures associated with SWS.
- Typically begin in childhood in the first year with unilateral brain invovlement
- Focal motor seizures are most common but complex partial seizures are also common
- Seizures stabilize in older childhood and worsen in adolescence
- AEDs are use and research suggests better cognitive functioning in those who are treated prophylactically
What is associated with better outcome in SWS?
- Later seizure onset (after 9-12 months of age)
- Good seizure control
- Unilateral brain involvement
Are those with SWS at risk for neurologic deterioration?
- Yes, thought to be due to venous occlusions and hypoxia and worsened by seizures
- Early onset dementia can be seen in individuals with SWS in their 50s and 60s
Describe the cognitive and behavioral functioning in those with SWS.
- Difficulty to determine d/t variable course and outcome
- Risk factors for worse outcome: frequent seizures, seizure onset in infancy, diffuse cortical involvement, hx of stroke-like episodes
- 60% of IQ scores in range of ID
- Learning, attention, processing speed, language, visual-perceptual, and sensorimotor problems are reported
- Disrupted behavior disorder is common
- Mood problems such as depression is common
- Substance-related disorders are common in adults
What is are the key physical & medical characteristics of Williams Syndrome?
- Connective tissue abnormalities
- Cardiovascular disease; supravalvar aortic stenosis
- Ocular/visual abnormalities: hyperopia, strabismus
- Ear/auditory abnormalities: chronic otitis media, hypersensitivity to sound
- Kidney/urinary tract abnormalities
- Facial dysmorphology