Inheritance Patterns Flashcards
45,X describes what disease?
Turner Syndrome: Characteristic physical abnormalities, such as short stature, swelling, broad chest, low hairline, low-set ears, and webbed necks. Girls with Turner syndrome typically experience gonadal dysfunction (non-working ovaries), which results in amenorrhea (absence of menstrual cycle) and sterility. Concurrent health concerns are also frequently present, including congenital heart disease, hypothyroidism (reduced hormone secretion by the thyroid), diabetes, vision problems, hearing concerns, and many autoimmune diseases. Finally, a specific pattern of cognitive deficits is often observed, with particular difficulties in visuospatial, mathematical, and memory areas
47,XXY describes what disease?
Klinefelter Syndrome: Principal effects include hypogonadism and reduced fertility. A variety of other physical and behavioural differences and problems are common, though severity varies and many XXY boys have few detectable symptoms.
Familial polydactyly (having supernumerary fingers or toes) exhibits what type of inheritance?
Autosomal Dominant
Tuberous Sclerosis (a rare multi-system genetic disease that causes hamartomas to grow in the brain and on other vital organs) exhibits what type of inheritance?
Autosomal Dominant
Diagnosis of Tuberous Sclerosis (hamartomas in CNS and skin) can be complicated clinically by:
Variable Expression
Diagnosis of Tuberous Sclerosis (hamartomas in CNS and skin) can be complicated molecularly by:
Mosaicism (Somatic or Germline)
Neurofibromatosis 1 (A developmental syndrome caused by germline mutations in neurofibromin, a gene that is involved in the RAS pathway and causes tumors along the nervous system. NF-1 often comes with scoliosis (curvature of the spine), learning difficulties, eye problems, and epilepsy) exhibits what type of inheritance?
Autosomal Dominant
Marfan syndrome (a genetic disorder of the connective tissue. People with Marfan tend to be unusually tall, with long limbs and long, thin fingers) exhibits what type of inheritance?
Autosomal Dominant
Achondroplasia (a common cause of dwarfism) exhibits what type of inheritance?
Autosomal Dominant (It occurs as a sporadic mutation in approximately 75% of cases: associated with advanced paternal age)
Defects in what gene are responsible for Marfan Syndrome (a genetic disorder of the connective tissue)?
Fibrillin
Defects in the Fibrillin gene are associated with what disease?
Marfan Syndrome: A genetic disorder of the connective tissue. The most serious complications are defects of the heart valves and aorta. It may also affect the lungs, the eyes, the dural sac surrounding the spinal cord, the skeleton and the hard palate
Defects in the Fibrillin gene of what chromosome cause Marfan syndrome (a genetic disorder of the connective tissue)?
Chromosome 15q
Defects in what gene are responsible for Achondroplasia (a common cause of dwarfism)?
FGFR3
Defects in the FGFR3 gene are associated with what disease?
Achondroplasia: A common cause of dwarfism. The disorder itself is caused by a change in the DNA for fibroblast growth factor receptor 3 (FGFR3), which causes an abnormality of cartilage formation.
Defects in the FGFR3 gene of what chromosome cause Achondroplasia (a common cause of dwarfism)?
Chromosome 4p
What are some characteristics of Autosomal Dominant inheritance?
50% of offspring of affected individuals are affected. Equal numbers of males and females affected. Vertical transmission. Unaffected members of a family do not have affected children. Variable expression is common. Decreased penetrance is possible. Isolated cases likely due to new mutation
What are some characteristics of Autosomal Recessive inheritance?
Parents are asymptomatic carriers of the condition. 25% chance of recurrence in siblings. Equal number of males and females affected. Horizontal transmission. Consanguinity is possible, especially in very rare conditions
Cystic Fibrosis (abnormal transport of chloride and sodium across an epithelium, leading to thick, viscous secretions) exhibits what type of inheritance?
Autosomal Recessive
Thousands of deleterious mutations in the CFTR gene are associate with what disease?
Cystic Fibrosis: An autosomal recessive genetic disorder that affects most critically the lungs, and also the pancreas, liver, and intestine. It is characterized by abnormal transport of chloride and sodium across an epithelium, leading to thick, viscous secretions
Mutations in what gene are associated with Cystic Fibrosis (abnormal transport of chloride and sodium across an epithelium, leading to thick, viscous secretions)?
CFTR
What is the most common mutation in Cystic Fibrosis (abnormal transport of chloride and sodium across an epithelium, leading to thick, viscous secretions)?
Delta-F508
Phenylketonuria (nonfunctional phenylalanine hydroxylase, the enzyme necessary to metabolize phenylalanine to tyrosine. Phenylalanine accumulates and is converted into phenylpyruvate, which is detected in the urine) exhibits what type of inheritance?
Autosomal Recessive
An error in the gene for what protein is associated with Phenylketonuria (phenylpyruvate detected in the urine)?
Phenylalanine hydroxylase (metabolizes phenylalanine to tyrosine
What are some characteristics of X-linked inheritance?
Incidence in males much higher than females. Heterozygous females may express the condition depending on pattern of X inactivation. Carrier females: 50% of sons affected, 50% of daughters are carriers. Affected males: all sons unaffected, all daughters are carriers (no male to male transmission). Affected males are typically related through females. Isolated cases usually due to new mutation
