Genetic Disease Clinical Approaches Flashcards
Genetic Counseling Definition
Process of helping people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease
6 Components of Genetic Counseling
Family/Medicical History Review (very thorough) Education Introduction of Management Options Targeted/Physical Exam Genetic Testing w/ Informed Consent Results Disclosure
Most Important Tool for Geneticists
Family History
5 Indications for Prenatal Screening/Testing
Advanced maternal age US abnormalities Family history of genetic disease Teratogenic exposures Maternal conditions
Central Tenant of Genetic Counseling
Non-Directiveness
GINA Protections (2)
Protects against health insurers/employers using predictive genetic information for policies/employment or requesting genetic testing for policy/employment
4 Things GINA Doesn’t Protect Against
Diagnostic test results or results in those manifesting disease
Disability/life/long-term care insurance discrimination
Apply to members of the military getting VA based healthcare
Employees of businesses w/ fewer than 15 employees (in theory)
9 Physical Landmarks of Face
Nasal bridge Pinna Tragus Nares Angle of Jaw Inner canthus Outer canthus Ala Philtrum
Dysmorphology
Discipline in human genetics to recognize physical anomalies of human morphology
5 Targeted Questions for Medical History
Multiple miscarriages Early deaths Early-onset cancer Intellectual disability Psychiatric disorders
5 Basic Elements of Pregnancy Genetic Medical History
Parental ages Maternal disease Teratogenic Exposures Fetal development Prenatal testing
3 Basic Elements of Perinatal Genetic Medical History
Gestational age
Delivery complications
Birth weight/length/head circumference
3 Basic Elements of Neonatal Genetic Medical History
Complications
Length of Newborn stay
Newborn screening
Major vs. Minor Malformations
Majors create significant medical problems that require a specific surgical or medical management, while minors don’t cause increased morbidity
Percentage of General Population w/ >0 Anomalies
30%
Disease that Becomes More Noticeable w/ Age
Mucopolysaccharidoses (MPS)
2 Diseases that Become Less Noticeable w/ Age
Noonan
Beckwith Wiedemann Syndrome (BWS)
Hypertelorism
Increased intercaranthal distance (larger than eye), w/ normal pupils
Telecanthus
Increased intercaranthal distance w/ decreased interpupillary distance
Smooth philtrum/small upper lip symptom of
FAS
5 Behavioral Abnormalities
Autism Hyperphagia (eating too much) Sleep disturbance Hypersociable personality Self-mutilation
2 Definitions of Multiple Congenital Anomalies (MCA)
2+ major malformations or 3+ minor malformations
4 MCAs from Numerical Autosomal Chromosome Abnormalities
Trisomy 21 (Down Syndrome) Trisomy 18 (Edwards syndrome) Trisomy 13 (Patau Syndrome)
Clinical Features of T21 (9)
Dysmorphic facial features Cardiac defects GI defects Eye anomalies ID Leukemia Hearing Loss Alzheimer's Hypothyroidism
Genetic Causes of DS (3.2)
95% from free T21 - 90% during oogenesis (usually Mei I) and 5% from spermatogenesis
4% Robertsonian
1% mosaic
Difference b/w Nondisjuction in Mei I and II
I: Homologous chromosomes fail to separate, have 2 chroms w/ different info
II: Sister ctids fail to separate, have 2 chroms w/ same info
3 Nonviable Robertsonian Inheritances
Monosomy 21
Trisomy 14
Monosomy 14
3 Viable Robertsonian Inheritances
Normal
Balanced Robertsonian
T21
Odds of Robertsonian Mother Having baby w/ DS
Should be 1/3, but most miscarried so more like 10-15%
5 Tests for T21 Patients
Complete blood count at diagnosis EKG at diagnosis Thyroid at 6/12 months then annually Annual ophthalmologic Annual audiologic
4 Common Symptoms of Edwards Syndrome (T18)
SGA
Clenched hands
Prominent occiput
Rocker-bottom feet
2 Genetic Features of T18
Usually nondisjunction in Mei II
80% females
Turner Syndrome 2 Genetic Features
Monosomy X
70% due to error in paternal gametogenesis, so remaining X is maternal
Cri-du-Chat Genetic features (cause and source)
5p15.2 deletion
De novo deletions usually
Williams Syndrome (cause and 3 features)
7q11.23 deletion
Puffy eyes, “cocktail party personality,” strong attraction to music
DiGeorge Syndrome (cause and source)
22q11 deletion Autosomal dominant (10% of parents have it!)
Rubinstein-Taybi Syndrome (cause and 2 symptoms)
Microdeletions of various genes, causes broad thumbs/big toe and distinct facial features
