Flashcards in Genetics Deck (42)
What is meant by a monogenic gene disorder?
Due to a single gene mutation
What are the 6 patterns of inheritance by which a monogenic gene disorder can be passed on?
X linked dominant
X linked recessive
What is meant by a polygenic gene disorder?
- Multiple genes involved
- Often environmental influences
- Evaluated by looking at large populations
Describe what is meant by high penetrance?
If the patient has the gene mutation they are extremely likely to have the disease
If both parents are carriers for a recessive mutation, what is the likelihood of the child inheriting the disease?
1 in 4
Autosomal dominant usually skips generations. TRUE/FALSE?
usually appears in every generation
If males can only pass a genetic disorder to females, but females can pass it to either sex, what pattern of inheritance is this?
If males are always affected, yet females can become carriers, what pattern of inheritance does this describe?
If only males are affected by a genetic disease, what does this indicate about its inheritance pattern?
It is Y-linked as only males have a Y-chromosome
Describe what is meant by a mitochondrial inheritance pattern
Inherited through mother's mitochondrial DNA whilst in the womb
=> can only inherit it from mother
Explain what benign tumours usually present in Multiple Endocrine Neoplasia Type 1 (MEN1)
- Non-secreting Islet cell tumour
- Non-secreting pituitary tumour
- adrenal cortex
What malignant tumour usually presents in MEN1?
Foregut carcinoid tumour
(secretes gastrin, glucagon and polypeptides)
What benign or malignant tumours are found in Multiple Endocrine Neoplasia Type 2?
What gene defect is found in Multiple Endocrine Neoplasia Type 2?
What hormones are secreted in Von Hippel Lindau syndrome?
What type of gene is the MEN1 gene
A tumour suppressor
What section of the MEN1 gene is usually mutated in Multiple endocrine Neoplasia Type 1?
Both MEN1 and MEN2 are autosomal dominant. TRUE/FALSE?
What section of the RET gene is usually mutated in MEN2 and what type of gene is it?
RET = proto-oncogene
MEN mutations in MEN1 usually occur in very specific areas of the codon. TRUE/FALSE?
RET mutations in MEN2 act in very specific cysteine residues, whereas in MEN1 they can occur anywhere along the length of the codon.
What three areas are usually affected by tumours in MEN1?
What tumour found during MEN1 is the most fatal?
Pancreatic neuroendocrine tumour
After what size should an MEN1 pancreatic tumour be referred for surgical intervention?
What tumours usually present in MEN2a?
Medullary Thyroid Carcinoma
What tumours are usually present in MEN2b?
Medullary Thyroid Carcinoma
**Marfan's Syndrome is also present**
What prophylactic treatment can be used in MEN2 for Medullary Thyroid Cancer?
At what age is it important to screen for Phaechromocytoma and Parathyroid disease?
Between ages 11 and 16
>11 = High Risk
>16 = moderate Risk
How do patients with Carney Complex usually present?
Spotty pigmentation of the skin:
Where do myxomas usually present in Carney Complex patients?
*generally myxomas can be cutaneous or mucosal*