Genetic Testing and Counseling Flashcards
(50 cards)
What is assortive mating?
Mating of people with the same phenotype resulting in more of the phenotype than expected
What is linguistic homogamy?
Mating between individuals that have the same language
What is the founder effect?
Common ancestor
Geographically or socially isolated
Mutated gene becomes more prevalent (AR)
What is a population bottleneck?
Reduction in population size
Enhanced effects of gene drift
If lots of people die, those genes will be lost
But the remaining genes will appear to increase greatly
What is balanced polymorphism?
A process of natural selection
Two alleles are maintained in stable equilibrium because the heterozygote is more fit than either of the normal or affected homozygotes
What does perinatal mean?
28 hours to 28 days of life
What are some known factors causing perinatal hearing loss?
Low birth weight
Time spent in NICU (longer the time the greater the risk)
Infections such as (sepsis, CMV, mumps, measles, rubella, and bacterial meningitis)
Use of ototoxic medication
Hypoxia (or prolonged use of oxygen)
What can help establish if the hearing loss was pre- or post-lingual?
Record of speech and language milestones
Can infants naturally coo and babble up to 6 months old?
Yes
Even babies with hearing loss
What may be an indication of vestibular dysfunction perinatally?
Poor motor development
What is the first thing you should ask when assessing someone with hearing loss?
Family history
Should all children with hearing loss undergo a complete physical examination?
Yes
To look for features associated with syndromic conditions
Should parents and siblings also be examined when a child is suspected to have a syndromic hearing loss?
Yes
To look for subtle signs
Can you complete a hearing test on young children?
No
You can do OAEs or ABRs instead
Should laboratory tests be ordered for every child with hearing loss?
No
It’s not cost effective or practical
When should laboratory tests be ordered for children?
When history, physical examination, and the age of the patient suggest it
What is the purpose of getting a laboratory test?
To exclude or confirm a specific suspected diagnosis
Are blood count tests helpful in establishing the cause of hearing loss?
No
Can a urine analysis be helpful?
Yes
Important for some conditions involving blood in the urine
Alport syndrome
Can congenital and acquired neonatal thyroid hormone deficiency result in profound intellectual disability often accompanied by deafness?
Yes
Early treatment can prevent severe hearing loss
Are the thyroid hormones in pendred usually normal?
Yes
What can an electrocardiogram tell us?
It calculates the QT interval
When is an electrocardiogram done?
If there is a family history of syncope or sudden infant death
May indicate JLNS
When are high-resolution CT scans of the temporal bones done?
When a child has progressive SNHL and craniofacial anomalies
