Congenital Defects and Teratology Flashcards
CONGENITAL DEFECTS AND TERATOLOGY
CONGENTIAL DEFECTS:
1. CONGENTITAL DEFECTS (BIRTH DEFECTS)- ALL STRUCTURAL AND
FUNCTIONAL ABNORMALITIES PRESENT BEFORE OR AT BIRTH
2. MAY BE APPARENT AT BIRTH, E.G. MEROMELIA
3. MAY NOT SHOW UP RIGHT AWAY, E.G. SOME OF THE HEART DEFECTS
4. DEFECTS VARY IN SEVERITY FROM MINOR TO INCOMPATIBLE W/ LIFE
5. IN GENERAL, THE EARLIER A PROBLEM OCCURS PRENATALLY, THE
MORE SERIOUS IT IS.
6. >20% OF INFANT DEATHS IN USA ARE CAUSED BY CONGENITAL DEFECTS
TERATOLOGY= STUDY OF ABNORMAL DEVELOPMENT/ CONGENITAL DEFECTS
1. CONCERNED WITH VARIOUS GENETIC AND ENVIRONMENTAL FACTORS THAT DISTURB NORMAL DEVELOPMENT
2. HELPS UNDERSTAND NORMAL AND ABNORMAL DEVELOPMENT
3. MAY ALLOW BETTER CONTROL OVER NORMAL DEVELOPMENT
4. MAY HELP PREVENT ABNORMAL DEVELOPMENT
HISTORY OF FIELD
POLYMASTIA - MANY MAMMARY GLANDS
1. KNOWN SINCE ANCIENT TIMES/ EGYPTIANS, PERUVIANS, EARLY ART
2. ORIGINALLY ASSOCIATED WITH DEVINE WILL, DEMONS, EVIL EYE;
MOTHER OFTEN BLAMED
3. ONLY RECENTLY REALIZED THESE ARE NOT CAUSES
4. NOW TOPIC OF CONSIDERABLE SCIENTIFIC STUDY
Polymastia=many mammary glands
crytorchism=testes remain in abdominal cavity
polydactale=too many fingers
osteogenesis imperfecta (fragile bones)
cystic fibrosis-respritory/intestine problem..sticky mucus
INCIDENCE OF DEFECTS IN HUMAN ORGANS
SLIDE: INCIDENCE OF DEFECTS IN HUMAN ORGANS AT BIRTH
- ORGANS SHOW DIFFERENT FREQUENCY OF CM
- BRAIN AND HEART HAVE A HIGH INCIDENCE
- EAR ALTHOUGH COMPLEX IN ORIGIN HAS LOW INCIDENCE
- SOME DEFECTS ARE NOT VISIBLE AT BIRTH BUT SHOW UP LATER
- SOME NEVER DIAGNOSED
PREVELANCE
1. 3-5% SHOW 1 OR MORE AT BIRTH
2. BY END OF 1 YEAR THIS = 5-10%
3. THE FREQUENCY OF A PARTICULAR DEFECT VARIES GEOGRAPHICALLY
A. ANECEPHALY IN 0.4% OF BIRTHS IN NORTHERN IRELAND BUT
ONLY 0.05% 9N WEST AFRICA
4. GIVEN COMPLEXITY OF DEVELOPMENT, AMAZING ANYONE IS NORMAL
FACTORS EFFECTING OCCURRENCE OF CONGENTIAL DEFECTS
- GENETIC
A. CHROMOSOMAL ABNORMALITIES - MAY BE NUMERICAL OR STRUCTURL
B. MUTANT GENES
C. ONLY RECOGNIZED RECENTLY (1940S) - ENVIRONMENTAL FACTORS
A. RUBELLA FIRST ENV FACTOR RECOGNIZED
B. INTRAUTERINE INJURY CAUSED BY DRUGS, RADIATION, INFECTION - MULTIFACTORIAL
A. COMBINATION OF GENETIC AND ENVIRONMENTAL FACTORS
CHROMOSOMAL ABNORMALITIES CAN BE EITHER NUMERICAL OR STRUCTURAL
TRIPLOIDY = EXAMPLE OF POLYPLOIDY = NUMERICAL PROBLEM
CHROMOSOMAL ABORMALITIES/ KARYOTYPE - USED TO STUDY
1. MAY BE NUMERICAL OR STRUCTURAL
2. NORMAL COMPLEMENT= 46 XX OR 46 XY
NUMERICAL/MOST IMPORTANT
1. POLYPLOIDY
A. CELLS HAVE MULTIPLES OF THE HAPLOID # OF CHROMOSOMES
B. TRIPLOIDY= TRIOS OF EACH CHROMOS.= 69XXX
1. MOST COMMON TYPE OF POLYPLOIDY IN HUMANS
2. DISPERMY COULD CAUSE IT OR FAILURE OF EGG TO CAST OFF 2ND PB
3. MAY DEVELOP OK 1ST 1/2 OF TERM THEN SICKEN AND DIE
4. A FEW HAVE BEEN BORN (PROB MOSAICS) BUT DIES SOON AFTER BIRTH
2. HAPLOIDY
A. 1/2 NORMAL # CHROMOSOMES
B. CAUSED BY PARTHENOGENESIS OR GYNOGENESIS (SPERM
ACTIVATES EGG BUT PLAYS NO FURTHER ROLE).
C. DO NOT DEVELOP BEYOND MID TERM
3. ANEUPLOIDY: A DEVIATION FROM THE DIPLOID # ( E.G.45=HYPODIPLOID)
A. MONOSOMY= ONE CHROMOSOME MISSING
1. MONOSOMY OF AUTOSOME CAUSES DEATH
2. MONOSOMY OF SEX CHROMOSOME- MANY DIE BUT SOME SURVIVE=
TURNERS (XO) SYNDROME.
A. USUALLY CAUSED BY NONDISJUNCTION IN THE MALE.
B. CHARACTERISTICS= WEBBED NECK, SWOLLEN HANDS,SHORT
STATURE, ABSENCE OF OVARIES, MENTAL RETARDATION
ANEUPLOIDY – another type of numerical defect – one too many or one too few chromosomes
Embryotoxic vs teratogenic
embryotoxic-kills embryo
teratogenic-congenital defect, not death
STRUCTURAL CHROMOSOMAL ABNORMALITIES
TRANSLOCATIONS
DELETIONS
DUPLICATIONS
INVERSION
ISOCHROMOSOME
STRUCTURAL ABNORMALITIES/STUDY INFO IN MOORE
1. INCLUDES TRANSLOCATIONS, DELETIONS, DUPLICATION, INVERSION, OR
ISOCHROMOSOME (CENTROMERE DIVIDES TRANSVERSELY NOT
LONGITUDINALLY)
NEXT SLIDE SHOWS AN EXAMPLE OF A DELETION
CRI DU CHAT – example of a deletion
CRI DU CHAT SYNDROME
1. CAUSED BY A PARTIAL TERMINAL DELETION FROM THE SHORT
ARM END OF CHROMOSOME #5.
2. ALL AFFLICTED INDIVIDUALS HAVE SEVERE MENTAL RETARDATION
3. MAY ALSO HAVE CONGENITAL HEART DISEASE AND A WEAK CAT
LIKE CRY
Rare about 1:50,000
ANGELMAN SYNDROME AND PRADER-WILLI SYNDROME
MICRODELETION ON CHROMOSOME #15
ANGELMAN
DEFECTIVE ALLELE ON #15 IS FROM MOTHER
MENTALLY RETARDED, CAN NOT SPEAK, POOR MOTOR DEVELOPMENT, INAPPROPRIATE LAUGHTER
PRADER-WILLI
DEFECTIVE ALLELE ON #15 IS FROM FATHER
OBESITY, MENTALLY RETARDED, HYPOGONADISM, CRYTORCHISIM
TWO INTERESTING DISTINCT MENTAL RETARDATION SYNDROMES
BOTH CAUSED BY THE SAME THING - MICRODELETION ON CHR #15
PHENOTYPES ARE VERY DIFFERENT - SEE PICTURES IN TEXT
ANGELMANS - DEFECTIVE #15 COMES FROM MOTHER
PRADER-WILLI - DEFECTIVE #15 COMES FROM FATHER
THE CRITICAL REGIONS FOR BOTH AS AND PWS ARE WITHIN THE 15Q REGION OF CHROMOSOME #15.
BUT THE CRITICAL REGIONS ARE SEPARATE WITHIN Q15
DEFECTIVE GENE IS AN IMPRINTED ONE - SO PHENOTYPE VARIES WITH SOURCE OF DEFECTIVE GENE (REVIEW IMPRINTING FROM EARLIER LECTURE)
NOTE: BOTH MALES AND FEMALES CAN INHERIT BOTH SYNDROMES
ANGELMAN’S: MENTAL RETARDATION, ABSENT SPEECH, SEIZURES, INAPPROPRIATE LAUGHTER, PECULIAR GAIT
PRADER-WILLI: MENTAL RETARDATION, HYPOGONADISM, HYPOTONIA, OBESITY
SYNDROMES CAN BE DETECTED BY FISH
MUTANT GENES CAN CAUSE ANOMALIES
SINGLE GENE DEFECTS
MUTANT GENES
1. SOME DEFECTS (ABOUT 8%) ARE CAUSED BY MUTANT GENES
2. USUALLY INVOLVES LOSS OR CHANGE IN FUNCTION OF A GENE
3. MOST MUTATIONS ARE HARMFUL
4. ARE INHERITED IN MENDELIAN MANNER
5. SOME EXAMPLES FOLLOW
AUTOSOMAL DOMINANT INHERITANCE
1. CAUSES DEFECT WHETHER HETEROZYGOUS OR HOMOZYGOUS
2. POLYDACTYLY, LOBSTER CLAW
3. ACHONDROPLASIA: MOST COMMON SKELETL DEFECT (1/15,000) - NORMAL IQ
A. 80-90% ARE NEW MUTATIONS - OCCURS IN ALLETHNIC GROUPS - HAS COMPLETE PENETRANCE
B. MAY BE ASSOCIATED WITH ADVANCED PATERNAL AGE
C. CAUSED BY A MUTATION IN FGF RECEPTOR3 - CAUSES DEFECT IN MATURATION OF CHONDROCYTES IN CARTILAGE GROWTH PLATE
4. OSTEOGENESIS IMPERFECTA: FRAGILE BONES WHICH FRACTURE PRENATALLY
AUTOSOMAL RECESSIVE
- RECESSIVE GENE EXPRESSES ITSELF ONLY WHEN HOMOZYGOUS INHERITED FROM BOTH PARENTS
- RARE /MANY CARRIERS REMAIN UNDETECTED
- E.G. MICROCEPHALY, CONGENITAL ADRENAL HYPERPLASIA
SEX LINKED INHERITANCE
- ABNORMAL GENES CARRIED ON X CHROMOSOME
- SEX LINKED DOMINATE NOT SHOWN FOR HUMAN
- RECESSIVE WOULD BE SHOWN IN XY BUT NOT XX/ ABOUT 300 FOR HUMANS
- TRANSMITTED FROM MOTHER TO SONS/ IN 1/2 SONS
- E.G., SLIDES: HYDROCEPHALUS (XS CSF), HEMOPHILIA
MUTANT GENES:
AUTOSOMAL RECESSIVE INHERITANCE
RECESSIVE MUTATION
AUTOSOMAL RECESSIVE
1. RECESSIVE GENE EXPRESSES ITSELF ONLY WHEN HOMOZYGOUS- INHERITED FROM BOTH PARENTS
2. RARE /MANY CARRIERS REMAIN UNDETECTED
3. CYSTIC FIBROUS IS CAUSED BY A RECESSIVE MUTATION
A. ABOUT 1 IN 23 PEOPLE IN US CARRY AT LAST ONE DEFECTIVE GENE
B. MOST COMMON GENETIC DEFECT OF ITS SEVERITY IN US
C. PEOPLE W/ CF HAVE CRONIC LUNG INECTIONS AND DIGESTIVE DISORDERS
D. LIFE EXPECTANCY NOW ABOUT 30 YEARS (USED TO BE 8 YEARS)
E. CAUSED BY DEFECT IN GENE PRODUCIN G PROTEIN CALLED CFTR
1. CONTROLS FLOW OF CHLORIDE ACROSS CELL MEMBRANE
3. OTHER DEFECTS THAT MAY BE INHERITED AS RECESSIVE MUTATIONS ARE. MICROCEPHALY, CONGENITAL ADRENAL HYPERPLASIA
MUTANT GENES: SEX-LINKED INHERITANCE
SEX LINKED INHERITANCE
- ABNORMAL GENES CARRIED ON X CHROMOSOME
- SEX LINKED DOMINATE NOT SHOWN FOR HUMAN
- RECESSIVE WOULD BE SHOWN IN XY BUT NOT XX/ ABOUT 300 FOR HUMANS
- TRANSMITTED FROM MOTHER TO SONS/ IN 1/2 SONS
- E.G., SLIDES: HYDROCEPHALUS (XS CSF), HEMOPHILIA
FRAGILE X SYNDROME
A. MOST FREQUENTLY INHERITED CAUSE OF MENTAL RETARDATION AFTER DOWNS SYNDROME
1. CAUSES 10% OF ALL CASES OF MENTAL RETARDATION
2. USUALLY FOUND IN MALES, BUT ALSO OCCURS IN FEMALES
B. JAW PROMINENT, EARS LARGE, FACE LONG AND NARROW BUT NOTICE HOW NORMAL THEY LOOK
C. A GENE (FMR-1 - FRAGILE X MENTAL RETARDATION GENE) ON LONG ARM OF X CHROMOSOME CAUSES AN UNSTABILE FRAGILE SITE IN CHROMOSOME
A. IF IN FMR1 GENE THERE ARE CGG REPEATS - IF FEWER THAN 40 REPEATS - NO PROBLEM
B. IF 55-200 REPEATS INDIVIDUAL HAS PREMUTATION STATE
C. MALES WITH MORE THAN 200 REPEAT HAVE SYNDROME
D. FEMALES WITH > 200 REPEATS HAVE ABOUT 50% OF HAVING LOW OR BORDERLINE IQ
1. FEMALES WITH >200 REPEATS W/ NORMAL IQ MAY HAVE LEARNING PROBLEMS
E. WHEN MORE THAN 200 REPEATS,GENE BECOMES METHYLATED - TURNED OFF
F. NO FMR1 PROTEIN IS MADE - CAUSES COGNITIVE FEATURES AND CONNECTIVE TISSUE PROBLEMS OF FRAGILE X
SIBS AT TOP. SISTER HAS MILD LEARNING DISABLITY - BOTH X CHROMOSOMES AFFECTED
C-KIT MUTATIONS/heterozygous mutation
MUTATIONS MAY AFFECT PHENOTYPE MILDLY WHEN HETEROZYGOUS
KIT MUTATION ON ONE ALLELE
HETEROZYGOUS FOR KIT
KIT IS NEED FOR CELL MIGRATIONS - E G., PGC, BLOOD CELLS, MELANOCYTES AND NCC
BOTH MOUSE AND BABY ARE HETEROZYGOUS - MAKE 1/2 NORMAL AMOUNT OF KIT GENE PRODUCT - NOT ENOUGH KIT GENE PRODUCT IS MADE FOR NORMAL MIGRATION OF ALL PIGMENT CELLS
NOTE THEIR PIGMENTATION IS AFFECTED
DEFECT IN KIT LIGAND (BINDS TO KIT) ON SURFACE OF CELLS ON MIGRATORY PATHWAY CAUSES SAME EFFECT
C-Kit heterozygous–>different color pattern
ENVIRONMENTAL FACTORS
INTRAUTERINE ENVIRONMENT
MECHANICAL DAMAGE
TERATOGENS
- INTRAUTERINE ENVIRONMENT
A. STRESS ON MOTHER MAY LEAD TO FETAL DEATH OR DEFECTS
B. STRESSES= UNDERNUTRITION, OVERFEEDING, VITAMIN DEFICIENCY, HOT CLIMATES
C. EMOTIONAL STRESS - NO NERVES IN PLACENTA
- CHEMICALS IN A STRESSED MOTHER MAY BE TRANSMITTED TO FETUS
- MECHANICAL DAMAGE
A. FETUS WELL PROTECTED BY UTERINE WALLS AND AMNIOTIC FLUID
B. SEVERE BLOWS OR FALLS MAY LEAD TO ABORTION/ USUSALLY
CAUSED BY HEMMORRAGE OF PLACENTA
C. AMNIOTIC BAND SYNDROME, OLLIGOHYDRAMNIOS - TERATOGENIC AGENT
A. ANY AGENT THAT CAN INDUCE OR INCREASE THE INCIDENCE OF
CONGENITAL DEFECTS - CAUSE 7% OF CONGENITAL MALFORMATIONS
- A TERATOGEN WILL PRODUCE A SPECIFIC EFFECT FOR A GIVEN
SPECIES WHEN APPLIED AT A SPECIFIC TIME AND DOSE
What is a teratogen?
Any agent that can produce a congenital anomaly or increase the incidence of an anomaly in the population.
Infectious agents
Drugs
Chemicals
Physical Agents
CRITICAL PERIODS OF DEVELOPMENT
- PRENATAL DEVELOPMENT MAY BE HAZARDOUS TO YOUR HEALTH
- THE CHANCES OF DEATH ARE GREATER BEFORE BIRTH THAN AT ANY
OTHER TIME EXCEPT OLD AGE - SOME EMBRYOS FAIL TO IMPLANT/DIE/RESORBED
- SOME LOST POST IMPLANTATIONS/STILLBIRTHS/ABORTIONS
- PROBABLY 50-90% OF THE EGGS WHICH GET FERTILIZED DO NOT
MAKE IT TO TERM - THOSE WHICH DO MAKE IT THRU ARE NOT ALWAYS OK
THIS FIGURE SHOWS WHEN IN PRENATAL DEVELOPMENT ORGAN SYSTEMS ARE MOST SENSITIVE TO TERATOGENS
TERATOGENS: CHEMICALS
METHYL MERCURY
PCBs (polychlorinated biphenyls)
THESE ARE PRESENT IN THE ENVIRONMENT
METHYL MERCURY MAY CAUSE CEREBRAL ATROPHY, SEIZURES, MENT RETARD
as loss of IQ points, and decreased performance in tests of language skills, memory function and attention deficits.
- PCBs MAY CAUSE INTRAUTERINE GROWTH RETARDATION, SKIN DISCOLORATION
FETAL ALCOHOL SYNDROME
A. ETOH ACTS AS A TERATOGEN DURING 1ST MONTH OF PREGNANCY
B. FAS SYNDROME MAY AFFECT EMBRYOS OF ALCOHOLIC WOMEN (40%)
C. MILD CASES (FETAL ALCOHOL EFFECTS -FAE) MAY AFFECT EMBRYOS OF WOMEN DRINKING 2-4 OZ OF ETOH/DAY
1. MAY OCCUR FROM A SINGLE BOUT OF BINGE DRINKING
D. FIRST REPORTED IN FRANCE IN 1960; IN ENGLISH LIT IN 1973
E. FAS IS PROBABLY MOST COMMON CAUSE OF MENTAL RETARDATION
(NON-CHROMOSOMAL)
E. SYMPTOMS OF FAS
1. GROWTH RETARDATION
2. MENTAL RETARDATION/LEARNING DISABILITES
3. FACIAL DEFECTS
4. MAY BE MILD OR VERY SEVERE
F. SLIDE: CUTE BABY ALMOST NORMAL - FACIAL CHARACTERS OF FAS
1. SMALL EYE OPENINGS
2. SMALL MAXILLA
3. SMOOTH PHILTRUM BUT LONG PHILTRUM
4. THIN UPPER LIP
G. FAS OCCURS ABOUT 2/1000 LIVE BIRTHS
H. COULD BE ELIMINATED IF PREGNANT WOMEN DID NOT DRINK
I. ETOH CAUSES: ABNORMAL MIGRATION OF NCC AND DEVELOPING NEURONS
1. ABSENCE OF NCC IN FRONTONASAL PROMINENCE CAN LAD TO MIDFACIAL ABNORMLITES
The following characteristics are commonly found in children with FAS:
In infancy, low birth weight, irritability, feeding difficulties, sleep disturbances, alcohol withdrawal, strong startle reflex
Growth deficiencies
Small head
Vision problems
Dental abnormalities
Hearing problems
Craniofacial abnormalities - narrow eye slits, flat midface, low nasal ridge, loss of groove between nose and upper lip, small jaw
Mental retardation, developmental delays
Learning disabilities
Neurological dysfunction - attention deficit, memory deficit, hyperactivity, difficulty with abstract concepts, poor problem solving skills and judgment, difficulty learning from consequences
Epilepsy
Behavioral problems - mood swings, defensive and stubborn, lack of self-discipline, genuine innocence, detached attitude
Organ and body dysfunction - muscle problems, bone and joint problems, genital defects, heart defects, kidney defects
FETAL ALCOHOL SYNDROME EXAMPLES
FAS in Different Ethnicities
HOLOPROSENCEPHALY
MORE SEVERE EFFECTS OF ETOH CONSUMPTION DURING PREGNANCY
HOLOPROSENCEPHALY:
A. INDUCTION OF FOREBRAIN IS DISTURBED
B. LEADS TO SPECTRUM OF ANOMALIES = HOLOPROSENCEPHALY
C. AFFECTS DERIVATIVES OF FRONTONASAL PROCESS, CALVARIA, MIDFACIAL STRUCTURES
D. MOST CASES OF HOLOPROS ARE \CAUSED BY ETOH CONSUMPTION WHEN FOREBRAIN INDUCTION OCCURS
E. WOMEN SHOULD NOT DRINK ETOH DURING FIRST MONTH OF PREGNANCY - EFFECTS ARE LESS SEVERE AFTER THIS TIME
MORE SEVERE CASES OF HOLOPROSENCEPHALY CAUSED BY ETOH
1. MISSING PHILTRUM
2. SINGLE NOSTRIL
3. NO NOSE - MIDFACIAL FEATURES DEPRESSED
4. CYCLOPIA - DEFECT IN FRONTONASAL PROMINENCE
MECHANISM OF ACTION - NOT WELL UNDERSTOOD
1. ETOH MAY DESTROY SOME CELLS IN DEVELOPING CNS AND INHIBIT FORMATION OF THE FOREBRAIN- M RETARD
3. ALSO INHIBITS MIGRATION OF NCC
A. NCC IMPRT IN BUILDING UP FACE - FRONTONASAL PROMIN
B. DEFICIENCIES IN FNP CAUSE FACIAL DEFECTS
J. MAY OCCUR IN 2/1000 BIRTHS , BUT MAY BE HIGHER
K. COULD BE PREVENTED BY NOT DRINKING DURING 1SY MONTH
G. OTHER CAUSES OF HOLOPROSENCEPHALY
A. INHALTION OF TOLUENE DURING PREGNANCY
B. DIABETIC WOMEN ARE AT HIGHER RISK
C. TRISOMIES 13,18 AND 21
D. SINGLE GENE MUTATIONS- MURINE KO OF SHH PRODUCES PHENOTYPE LIKE HUMAN HPE
ACCUTANE
VITAMIN A ANALOGUE
SPONTANEOUS ABORTION
MICROGNATHIA
MICROTIA
CARDIAC DFFECTS
NEURAL TUBE DEFECTS
CLEFT PALATE
ACCUTANE: = 13-CIS-RETINOIC ACID
A. A PRESCIPTION MEDICATION USED TO TREAT ACNE
B. A SYNTHETIC DERIVATIVE OF VITAMIN A
C. APPROVED BY FDA IN 1982
D. HIGH PROBABLY OF BIRTH DEFECTS IF TAKEN DURING PREGNANCY
E. DEFECTS INCLUDE:
1. HYDROCEPHALY
2. MICROCEPHALY
3. MENTAL RETARDATION
4. SMALL/MALFROMED EARS
5. FACIAL ABNORMALITIES
6. HEART DEFECTS
7. OPEN NTD - SPINA BIFIDA CYTSICA
8. MISCARRIAGE
F. TEGISON IS A RELATED DRUG- VITAMIN A RELATED
1. USED TO TREAT PSORIASIS
2. MAY CAUSE DEFECTS
G. FOODS LIKE TOMATOES, CARROTS YELLOW VEGGIES?
1. OK TO EAT WHILE PREGNANT
2. CONTAIN B-CAROTENE - PRECURSOR OF VIT A
3. BODY MAKES JUST ENOUGH VIT A - SO THESE ARE NOT DANGEROUS
4. BUT SHOULD NOT TAKE TOO MUCH VIT A SUPPLEMENT WHILE PREGNANT
FETAL SMOKING SYNDROME
FETAL SMOKING SYNDROME
- SMOKERS EXPOSE FETUS TO MS AND ETS
- SMOKE CONMPONENTS CROSS PALCENTA
- RETARD GROWTH - LOWER BIRTH WEIGHT BABIES FOR MOTHERS WHO SMOKE
- ALSO SMOKING HAS BEEN LINKED TO INFERTILITY, ECTOPIC PREGANCY, ABRUPTIO PLACENTA, SIDS, POST NATAL LEARNING DISABILITES
- SLIDE SHOWS A CRYSTAL OF NICOTINE
OTHER TERATOGENS??
A. CAN BE HARD TO ESTABLISH IF A COMPOUND IS A TERATOGEN
B. THERE IS A RARE CM CALLED GASTROSCHISIS - SPLIT OPEN STOMACH
C. VENTRAL BODY WALL THIN AND TEARS - INTESTINE COME OUT
D. IT IS INCREASING - WHY?
1. EVIDENCE THAT IT MAY BE PROVOKED BY COCAINE
2. ALSO BY PSEUDOEPHRINE - OVER THE COUNTER DECONGENSTANT
- SOME GOOD NEWS!!
A. NEURAL TUBE DEFECTS - NEURULATION DOES NOT OCCUR PROPERLY
- SLIDE: SEM SHOWING YOUNG EMBRYO W/ ANENCEPHALY
- SLIDE: ANENCEPHALY AND RACHISCHISIS
- SLIDE: A FORM OF SPINA BIFIDA
- MAY BE CAUSED BY GENETIC FACTORS OR BY SOME ERATOGENS (ACCUTANE)
B. CAN BE PREVENTED IN SIGNIFICANT # OF CASES IF WOMAN TAKES FOLIC ACID BEFORE CONCEPTION - 400 MG/DAY
- THIS AMOUNT IS FOUND IN CENTRUM!!
THIS IS A GOOD TIME TO REVIEW THE METHODS TO STUDY CHROMOSOMES
LEFT = FISH - FLUORESCENCE IN SITU HYDRIDIZTION
FLUORESCENT PROBE TO CHROMOSOME 21 USED TO LABEL
FAR LEFT IS NORMAL KARYOTYPE = 2 COPIES OF 21
MIDDLE FIGURE SHOWS INDIVIDUAL WITH DOWN’S
3 COPIES OF #21
RIGHT SHOWS CHROMOSOMAL PAINTING
DIFFERENT FLUORECHROMES SPECIFIC FOR EACH PAIR OF CHROMOSOMES IS USED TO PAINT CHROMOSOMES
CAN EASILY IDENTIFY TRISOMIES, MONOSOMIES OR TRANSLOCATIONS
