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30 Cards in this Set
- Front
- Back
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Medical Genetics
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are health professionals who are dedicated to using and interpreting genetic information to maintain and improve the health of individuals, their families and communities
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Clinical Geneticists
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are involved in the diagnosis, counseling, and care of individuals and families with genetically influenced health problems, including inherited, teratogenic, or sporadic conditions.
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Why make a genetic diagnosis?
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Defines the gamut of abnormalities present (what should and should not be expected)
Provides prognosis for the future Explains why the condition occurred Allows for genetic counseling of all family members re: recurrence risk |
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When to consult a Clinical Geneticist…
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Prenatal test(s) showing abnormalities
Infant with one or more birth defects, an unusual appearance, or an abnormal genetic test results (chromosome testing, newborn metabolic screening) Child or adult with an unusual appearance, intellectual disability, or history of birth defect(s) Family history of birth defect(s) or inherited conditions Infertility or recurrent miscarriages Abnormal state metabolic newborn screen Early onset cancer/strong family history of cancer |
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Overview of Clinical Genetics
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Review history and examine patient
Obtain family history Derive a general impression Recommend diagnostic testing Determine best diagnosis Counsel individual and family re:disease, prognosis, options, treatment, recurrence |
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Overview of Clinical Genetics
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Review history and examine patient
Obtain family history Derive a general impression Recommend diagnostic testing Determine best diagnosis Counsel individual and family re:disease, prognosis, options, treatment, recurrence |
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Birth Defect
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a condition present at birth which requires medical, surgical or cosmetic intervention.
Diagnosed in 3% of children at birth By 1 year of life, 4% of children will have some type of birth defect diagnosed |
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Example of Birth Defects
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neural tube defect
congential heart disease polydactyly cleft lip |
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Clinical Dysmorphology
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Evaluation for mild dysmorphic features
features found in a relatively small percentage of the entire population or features which have been found to occur more commonly in genetic syndromes 3 or more dysmorphic features / minor anomalies strongly correlate with a possible genetic syndrome MINOR BIRTH DEFECT; DOCTORS LOOK FOR SUBTLE PHYSICAL DIFFERENCES THAT MAY CLUE THEM INTO A SIGNIFICANT PROBLEM few little things can cause a bigger problem |
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EXAMPLE OF MINOR ANOMALIES
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preericular earpit
polydactyl single palmer crease (common with individuals who have down syndrome) pectue excevactum (chest wall deformity) hyoertelorism (eyes far apart) |
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Syndrome
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recognizable pattern of multiple anomalies thought to be pathogenetically related
- recognizable patterns were given syndrome names that is due to 1 unifying pathogenic mechanism |
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examples of syndrome
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down syndrome
neurofibromatosis type 1 progeria |
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Association
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a non-random occurrence in two or more individuals of multiple anomalies
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Example of Association
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VACTERL
Vertebrae Anal anomolies Cardiac Tracheo-Esophageal fistula Renal anomolie Limb anomoly |
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Sequence
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a pattern of multiple anomalies derived from a single known or presumed prior anomaly or mechanical factor
- think as mechanical as opposed to hereditary or teratogen |
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Example of sequence
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- Pierre Robin Sequence
- Potter Sequence - CHARGE |
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Malformation
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a morphologic defect of an organ, part of an organ, or a larger region of the body resulting from an intrinsically abnormal developmental process
- birth defects are malformations jackie - program not working properly - something wrong with progran |
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Example of malformation
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- cleft lip
- polydactyl - syndactyl of foot |
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Deformation
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an abnormal form or position of a part of the body caused by non-disruptive mechanical forces
jackie - intrinsic property is fine but something spacially is causing this birth defect - |
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Example if Deformation
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congenital dislocation of the hip, clubfoot (an abnormal intrauterine position) due to breech position
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Disruption
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a morphologic defect resulting from a breakdown of, or interference with, an originally normal developmental process
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Example of disruption
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amniotic band syndrome resulting in amputation of a finger
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Dysplasia
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Abnormal cellular organization or function within a specific tissue type throughout the body, resulting in clinically apparent structural changes
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Example of Dysplasia
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hemangioma or skeletal dysplasia such as osteogenesis imperfecta
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Causes of Birth Defects
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1. Chromosome abnormalities 10%
2. Single gene defects 3% 3. Multifactorial 23% 4. Prenatal teratogen exposure 3% 5. Uterine 2.5% 6. Twinning 0.4% 7. Unknown 43.2% |
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Teratogens
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substances that a pregnant woman may be exposed to which can lead to birth defects in her fetus
- The effect on the fetus is highly dependent on the gestational age at time of exposure and dose |
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Example if Teratogens
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Infectious (rubella, syphilis, CMV, others)
Medications (thalidomide, Accutane, antiepileptics) Drugs of abuse (cocaine, alcohol) External Agents (radiation, hyperthermia) Maternal Disorders (diabetes, lupus, PKU) |
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Ex of drug abuse
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FETAL ALCOHOL SYNDROME
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Diagnostic Evaluation
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Pregnancy History
Birth History Medical History Developmental History Family History Physical Examination |
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Pregnancy History
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- mom age over 35 > increase risk with chromosomal anomaly ie down syndrome (trisomy 21)
- maternal illnes > diabetes mellitus can cause birth defects - exposure to teratogens |
