Podcast
Questions and Answers
What condition is associated with a characteristic 'white forelock' of hair and congenital sensorineural hearing loss?
What condition is associated with a characteristic 'white forelock' of hair and congenital sensorineural hearing loss?
In which syndrome is the mechanism described as a failure of radial migration of neurons?
In which syndrome is the mechanism described as a failure of radial migration of neurons?
What is a common behavioral finding in Rett syndrome?
What is a common behavioral finding in Rett syndrome?
Which chromosomal deletion is associated with Cri-du-Chat syndrome?
Which chromosomal deletion is associated with Cri-du-Chat syndrome?
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What genetic inheritance pattern is primarily involved in Angelman syndrome?
What genetic inheritance pattern is primarily involved in Angelman syndrome?
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Which syndrome is characterized by hyperphagia and mental retardation, and involves maternal imprinting?
Which syndrome is characterized by hyperphagia and mental retardation, and involves maternal imprinting?
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Which of the following is NOT a feature of Friedreich ataxia?
Which of the following is NOT a feature of Friedreich ataxia?
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What is the typical presentation of patients with Angelman syndrome often described as?
What is the typical presentation of patients with Angelman syndrome often described as?
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What is the hallmark skin manifestation of Neurofibromatosis type I?
What is the hallmark skin manifestation of Neurofibromatosis type I?
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Which of the following is not associated with Neurofibromatosis type II?
Which of the following is not associated with Neurofibromatosis type II?
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What genetic condition is linked to the Tuberous sclerosis complex?
What genetic condition is linked to the Tuberous sclerosis complex?
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In the Rinne test, which condition is indicated if bone conduction is greater than air conduction?
In the Rinne test, which condition is indicated if bone conduction is greater than air conduction?
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Which type of tumors are characteristic of Von Hippel-Lindau syndrome?
Which type of tumors are characteristic of Von Hippel-Lindau syndrome?
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How is the Weber test conducted?
How is the Weber test conducted?
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What type of spots are associated with Tuberous sclerosis?
What type of spots are associated with Tuberous sclerosis?
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Which of the following best describes Sturge-Weber syndrome?
Which of the following best describes Sturge-Weber syndrome?
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What is the genetic inheritance pattern for Neurofibromatosis type I (NF1)?
What is the genetic inheritance pattern for Neurofibromatosis type I (NF1)?
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Which condition is commonly associated with bilateral acoustic schwannomas in adults?
Which condition is commonly associated with bilateral acoustic schwannomas in adults?
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What is a common skin manifestation found in Tuberous sclerosis?
What is a common skin manifestation found in Tuberous sclerosis?
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Which brain tumors are associated with Neurofibromatosis type I?
Which brain tumors are associated with Neurofibromatosis type I?
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What is a characteristic feature of the Rinne test in normal hearing individuals?
What is a characteristic feature of the Rinne test in normal hearing individuals?
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Which condition is associated with mutations in the VHL gene?
Which condition is associated with mutations in the VHL gene?
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Which of the following statements is true regarding the Weber test?
Which of the following statements is true regarding the Weber test?
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What is the primary characteristic of Waardenburg syndrome?
What is the primary characteristic of Waardenburg syndrome?
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Which of the following is a feature of Von Hippel-Lindau syndrome?
Which of the following is a feature of Von Hippel-Lindau syndrome?
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Which syndrome includes the symptom of 'hand-wringing' or 'hand-flapping'?
Which syndrome includes the symptom of 'hand-wringing' or 'hand-flapping'?
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What is a common diagnostic imaging finding in Tuberous sclerosis?
What is a common diagnostic imaging finding in Tuberous sclerosis?
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What genetic mechanism leads to Angelman syndrome?
What genetic mechanism leads to Angelman syndrome?
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Which condition is caused by a deletion on the short arm of chromosome 5?
Which condition is caused by a deletion on the short arm of chromosome 5?
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Which type of freckling is characteristic of Neurofibromatosis type I?
Which type of freckling is characteristic of Neurofibromatosis type I?
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Which term best describes the physical symptom of Friedreich ataxia?
Which term best describes the physical symptom of Friedreich ataxia?
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What is a common feature of Prader-Willi syndrome?
What is a common feature of Prader-Willi syndrome?
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What is the underlying genetic issue in Double cortex syndrome?
What is the underlying genetic issue in Double cortex syndrome?
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In the context of Angelman syndrome, what occurs due to paternal imprinting?
In the context of Angelman syndrome, what occurs due to paternal imprinting?
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Which syndrome is specifically described as affecting only female infants?
Which syndrome is specifically described as affecting only female infants?
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What is a recognized symptom of Rett syndrome relating to behavior?
What is a recognized symptom of Rett syndrome relating to behavior?
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Study Notes
Genetic Syndromes
- Waardenburg syndrome: Congenital sensorineural hearing loss and pigmentary changes (hair and skin). Characterized by a "white forelock" and caused by neural crest migration failure. May appear in young children.
- Double cortex syndrome: Rare genetic condition where neurons fail to migrate properly in the cortex, resulting in two grey matter layers. USMLE focus is on radial migration failure.
- Rett syndrome: Exclusively affects female infants, causing neurologic degeneration. Key characteristic is hand-wringing or hand-flapping. Mental regression can manifest as mouthing of objects.
- Cri-du-chat syndrome: Chromosome 5 deletion. Infants have a distinctive, cat-like cry. Associated with mental retardation, distinctive facial features, and microcephaly.
- Friedreich ataxia: Autosomal recessive GAA trinucleotide repeat disorder. Causes ataxia, kyphoscoliosis, cardiomyopathy, high arched feet (pes cavus), hammer toes, and early-onset type II diabetes.
- Angelman syndrome: "Happy puppet" phenotype; characterized by laughter. Caused by paternal imprinting deletion or mutation. The maternal gene is normally expressed, but in this case, it is deleted or mutated which results in no/little maternal gene expression. Also possible via paternal uniparental disomy, resulting in both imprinted paternal alleles, leading to no maternal gene expression.
- Prader-Willi syndrome: Mental retardation and hyperphagia. Caused by maternal imprinting deletion or mutation. The paternal gene is normally expressed, but in this case, it is deleted or mutated which results in no/little paternal gene expression. Can occur via maternal uniparental disomy, resulting in both imprinted maternal alleles, leading to no paternal gene expression.
Phakomatoses (Neurocutaneous Disorders)
- Neurofibromatosis type 1 (NF1): Autosomal dominant (AD), chromosome 17. Characterized by neurofibromas, café au lait spots (hyperpigmented macules), axillary/groin freckling, Lisch nodules (iris hamartomas), pheochromocytoma, and risk of optic nerve glioma, oligodendroglioma, and ependymoma.
- Neurofibromatosis type 2 (NF2): AD, chromosome 22. Can present with bilateral cataracts in children and bilateral acoustic schwannomas and meningiomas in adults.
- Tuberous sclerosis (TSC): AD, caused by TSC1/2 gene mutations. MRI shows periventricular nodules. Associated with seizures, facial/skin lesions (angiofibromas, subungual fibromas), renal angiomyolipomas, cardiac rhabdomyomas, hypopigmented macules ("ashleaf spots"), and hyperpigmented velvety lesions ("shagreen patches").
- Von Hippel-Lindau (VHL): AD, chromosome 3. Causes cerebellar/retinal hemangioblastomas, bilateral renal cell carcinoma, and pancreatic cysts. The mutation leads to constitutive activation of hypoxia-inducible factor, a protein related to blood vessel growth.
- Sturge-Weber syndrome: Not inherited; somatic mosaicism of the GNAQ gene.
Hearing Tests
Rinne Test
- Compares bone conduction and air conduction to assess hearing. A vibrating tuning fork is placed against the mastoid bone (bone conduction), and when the sound is no longer heard, the fork is placed in front of the ear (air conduction).
- Normal/sensorineural hearing loss: Air conduction (AC) is better than bone conduction (BC).
- Conductive hearing loss: Bone conduction (BC) is better than air conduction (AC).
Weber Test
- Used to identify the location of hearing loss.
- A vibrating tuning fork is placed on the forehead.
- Normal hearing: Sound is heard equally in both ears.
- Conductive hearing loss: Sound is lateralized to the affected ear (louder in affected ear).
- Sensorineural hearing loss: Sound is lateralized to the unaffected ear (louder in the unaffected ear).
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Description
Explore various genetic syndromes such as Waardenburg, Rett, and Cri-du-chat in this informative quiz. Delve into their characteristics, symptoms, and genetic implications. Test your knowledge of these conditions and their impact on individuals.
