Which of the following chromosomal abnormalities are associated with brain tumours? 1. Neurofibromatosis type 1 2. Neurofibromatosis type 2 3. Peutz-Jeghers syndrome 4. Hereditary nonpolyposis colorectal cancer Select the correct answer using the code given below.
Genetic Syndromes and Brain Tumor Associations
This question asks to identify which listed genetic syndromes are associated with the development of brain tumors. We will examine each syndrome.
Syndrome 1: Neurofibromatosis Type 1 (NF1)
NF1 is an autosomal dominant disorder caused by mutations in the NF1 gene. It is strongly associated with various tumors, including brain tumors like optic gliomas and astrocytomas.
Syndrome 2: Neurofibromatosis Type 2 (NF2)
NF2 is also an autosomal dominant disorder, linked to mutations in the NF2 gene. This syndrome is primarily characterized by the development of brain tumors, particularly vestibular schwannomas (acoustic neuromas), meningiomas, and ependymomas.
Syndrome 4: Hereditary Nonpolyposis Colorectal Cancer (Lynch Syndrome)
Lynch syndrome is associated with mutations in DNA mismatch repair genes. While primarily known for colorectal and other extracolonic cancers, defects in DNA repair can potentially increase the risk for various malignancies, including, in some contexts, central nervous system (CNS) tumors, though this association is less direct than for NF1 and NF2.
Syndrome 3: Peutz-Jeghers Syndrome (PJS) Exclusion
Peutz-Jeghers syndrome is linked to mutations in the STK11 gene. It is characterized by hamartomatous polyps in the gastrointestinal tract and an increased risk of various cancers, predominantly in the GI system, breast, and ovaries. Brain tumors are not a recognized feature of PJS.
Conclusion on Associations
Based on the established medical understanding:
- Neurofibromatosis type 1 (NF1) is associated with brain tumors.
- Neurofibromatosis type 2 (NF2) is strongly associated with brain tumors.
- Hereditary nonpolyposis colorectal cancer (Lynch syndrome) has recognized associations, albeit less direct, with CNS involvement.
- Peutz-Jeghers syndrome is not typically associated with brain tumors.
Therefore, syndromes 1, 2, and 4 are associated with brain tumors.
The correct option is the one that includes 1, 2, and 4.
Important Questions from Brain & Nervous System Surgery
Consider the following clinical features:
1. Raised ICP
2. Seizures
3. Focal deficit
4. Headache
Which of the above clinical features are related to most brain tumours?
- The most common type of brain tumours associated with neurofibromatosis type 1 brain tumour syndrome is
Upper motor neuron lesions are characterized by which of the following?
1. Increased tone spasticity
2. Hyperreflexia
3. Absent plantar response
4. Motor weakness
Select the correct answer using the code given below.
A comatose patient after sustaining severe head injury has been admitted in neurosurgical ICU. Which of the following parameters should ideally be maintained in this patient ?
1. $pCO_2 = 4.5 – 5.0$ kPa ($33-38$ mm Hg)
2. MAP = $80 – 90$ mm of Hg
3. $pO_2 > 11$ kPa ($> 80$ mm Hg)
4. $Na^+ < 130$ meq/L
Select the correct answer using the code given below :
- A patient with suspected head injury is brought to the emergency following road traffic accident. At the time of examination, patient is conscious with GCS 14/15 and stable vitals. There is bleeding from right ear and CSF leak from nose. Bruising is present behind the right ear. The most probable clinical diagnosis in this patient is
