Topic 8.4 - Congenital and Mood Disorders Flashcards
What is hydrocephalus?
Congenital Disorder
–> Excess CSF accumulating within the skull
What are the two kinds of hydrocephalus?
- Non-communicating
- Communicating
What are some possible causes for hydrocephalus?
Developmental Abnormalities (most common)
–> Stenosis
–> Atresia
Obstruction from tumors, infection, or scar tissue (can occur at all ages)
What is non-communicating hydrocephalus?
Flow of CSF through the ventricular system is blocked, usually results in fetal developmental disorder.
Obstruction can lead to backpressure of fluid in ventricles, with can compress blood vessels nearby.
What are some possible causes for non-communicating hydrocephalus?
Fetal developmental Tube Disorders
–> Myelomeningecele
–> Arnold-Chiari malnormation
What is the Arnold-Chiari malformation?
When the lower part of the brain pushes down into the spinal canal.
What is communicating hydrocephalus?
When the absorption of CSF through subarachnoid villi is impaired.
How does communicating hydrocephalus impact neonates as compared to older children or adults?
Neonates
–> The skull can expand to a certain degree to relieve pressure. However, without treatment permanent brain damage can occur.
Older Children and Adults
–> ICP increases more rapidly than in neonates due to no room for accommodation.
What is spina bifida?
A group of neural tube defects of varying severity
Is spina bifida caused by genetic or environmental factors? What kinds of factors contibute to its development?
Both
Environmental factors might include radiation, gestational diabetes, or deficiencies of folic acid.
What are the three kinds of spina bifida?
- Spina bifida occulta
- Meningocele
- Myelomeningocele
What is spina bifida occulta?
A congenital defect where the spinous processes do not fuse, but herniation of the spinal cord and meninges does not occur.
Defect might not be visible, and is diagnosed by routine radiograph or on the basis of mild neurological signs.
What is meningocele?
A congenital defect where the spinous processes do not fuse and herniation of the meninges occurs through the defect.
The meninges and CSF form a sac on the surface, with the absence of nerve tissue in the sac.
What is myelomeningocele?
A congenital defect where the spinous processes do not fuse and herniation of the meninges, CSF, and spinal cord occurs through the defect.
–> Involves considerable neurological impairment
What kinds of spina bifida are visible as protrusions over the spine?
Meningocele and myomeningocele
What kinds of impairments are associated with spina bifida?
–> Neurological deficit
–> Sensory of motor function below the level of herniation is often impaired
What is cerebral palsy?
A group of disorders with some degree of motor impairment
–> Palsy means weakness or problems with using muscles
What usually causes cerebral palsy?
Perinatal Brain Damage
–> Hypoxia
–> Infection
–> Metabolic abnormalities
What are the three classifications of cerebral palsy?
- Spastic paralysis of leg muscles
- Dyskinetic disease
- Ataxic cerebral palsy
What kind of cerebral palsy impacts the most individuals?
Spastic paralysis of leg muscles
What is dyskinetic cerebral palsy? Damage to which structure causes it?
Uncontrolled involuntary movements
–> Usually results from damage to basal nuclei or cranial nerves
What is ataxic cerebral palsy? Damage to which structure causes it?
Trouble with balance or coordination
–> Damage to cerebellum
Which part of the neuron has synaptic vesicles filled with NTs?
The end bulb
What actin-based structure is dynamic and highly motile, and found at the end of a developing axon to facilitate axon guidance during growth?
A growth cone.
What is a major inhibitory NT in the brain?
Gaba
What is a major excitatory NT in the brain?
Glutamine
Individuals with autism often present with other psychiatric conditions such as…
Intellectual disability, epilepsy, motor learning delay, anxiety, ADHD
What are copy number variants?
When a person has one less or more copy of a chromosome (1 or 3)
What are single nucleotide variants?
A point mutation in a nucleotide that changes a protein.
What is a de novo mutation?
One that is not inherited.
What percentage of causes of autism are genetically inherited genes? de novo genes? Environmental?
Inherited
–> ~50%
De Novo
–> 9.5%
Environment
–> 38.1%
What three kinds of genes are involved in genetic causation of autism?
–> Chromatin remodeling
–> Protein syntheses
–> Synaptic function
What is Rett syndrome? Who does it affect?
Patient develops normally for first 6-18 months of age, followed by a period of loss of learned language skills and purposeful hand movements.
–> 1 in 10,000 females
What causes Rett syndrome? Are these mutations inherited?
A mutation in X linked gene encoding for Mythyl-CpG binding protein 2 (MeCP2) accoutns for ~95% of Re3tt syndrome.
–> often de novo
Mutations in what gene account for ~95% of Rett syndrome?
MeCP2
What is the role of MeCP2?
To act as a repressor or activator, depending on where it is acting
What are the symptoms of Fragile X syndrome?
–> Language delay
–> Hyperactivity
–> Social anxiety
–> Impulsivity
Generally, autistic-like behaviours
What causes fragile X syndrome?
A mutation of the FMR1 gene on the X chromosome.
–> Causes an usual number of CGG repeats on the gene, some patients have an expansion mutation of 200+ units.
What is synaptic E/I imbalance? What causes it?
An imbalance of excitatory and inhibitory neuronal and postsynaptic recognition, caused by adhesion molecules.
–> Associated with ASD
What is 16p11.2 microdeletion associated with?
One of the most common deletion associated with 550 kb of genomic loss
–> Associated with increased risk for ASD and motor learning delay
What is an early sign for ASD in infants?
Greater sensitivity to light touch and touch avoidance can predict deficits in social development
Sensory overresponsivity in ASD is strongly correlated to…
Anxiety and GI dysfunction
