In Leber's hereditary optic neuropathy, vision loss is _____ (central/peripheral).
Autosomal-dominant patterns of inheritance are often found in diseases caused by defects in _____ genes.
Structural; as opposed to recessive diseases, which are often caused by faulty enzyme genes
True or False: A mother with an X-linked dominant disease may pass the disease only to her sons.
False; both her sons and her daughters may be affected
True or False? Patients with autosomal-dominant disorders often present clinically after puberty.
True; in order for the diseases to remain in the population, affected people must have offspring
What is the pattern of inheritance of hypophosphatemic rickets?
What is the mode of inheritance if a disease is present in many generations and affects both males and females in roughly equal proportions?
What is the mode of inheritance in a family in which a disease is transmitted only through the mother and all children (both boys and girls) are affected?
Autosomal-recessive patterns of inheritance are often found in diseases caused by defects in _____.
Enzymes; as opposed to dominant diseases, which are often caused by faulty structural genes
True or False? A mother may pass a disease with a mitochondrial pattern of inheritance to both her sons and her daughters.
What is the mode of inheritance if a gene is present in a single generation and 25% of the offspring from the same two parents have the disease?
What is the pattern of inheritance of Leber's hereditary optic neuropathy?
Do patients with dominant or recessive diseases generally present at a younger age?
What would you expect to see on urinalysis in a patient with hypophosphatemic rickets?
You would expect an increased urine phosphate level since there is proximal tubule phosphate loss
Variable expression of mitochondrial diseases can be accounted for by what phenomenon?
True or False? Hypophosphatemic rickets can be treated by vitamin D supplementation.
False; this disease is also known as vitamin D-resistant rickets
What is the mechanism of phosphate wasting in hypophosphatemic rickets?
There is increased phosphate wasting at the proximal renal tubule
Which cells are affected in Leber's hereditary optic neuropathy?
There is degeneration of retinal ganglion cells and their axons
In general, are autosomal dominant or autosomal-recessive disorders more severe?
What is the mode of inheritance in a family in which 50% of sons are affected and there is no male-to-male transmission?
What percentage of sons of a carrier mother are expected to inherit an X-linked recessive disease?
True or False? X-linked recessive diseases are commonly more severe in males than in females.
True or False? A mother with an X-linked dominant disease may pass the disease to either her sons or her daughters.
True or False? A father with an X-linked dominant disease will pass the disease to all of his daughters but none of his sons.
A mother with achondroplasia is pregnant; assuming that the father does not have this condition, what is the likelihood that her child will also have the disease?
50%; achondroplasia is an autosomal-dominant disease
Achondroplasia is the result of a defect in the _____ receptor.
Fibroblast growth factor 3
Describe the clinical manifestations of achondroplasia.
Patient has dwarfism with short limbs but a normally sized head and trunk
What parental attributes are associated with achondroplasia?
Advanced paternal age
What is the mode of inheritance of autosomal-dominant polycystic kidney disease?
Autosomal-dominant polycystic kidney disease is associated with what cardiac pathology?
Mitral valve prolapse
A 50-year-old man has hematuria, hypertension, and progressive renal failure. His kidneys are both massively dilated as a result of multiple large cysts. What is the most likely diagnosis?
Autosomal-dominant polycystic kidney disease