teratogens and birth defects

Birth DefectsBirth Defects

Lizamarie Campoamor-OlegarioLizamarie Campoamor-Olegario

Birth DefectsBirth Defects

an abnormality of an abnormality of – structure, structure, – function or function or – metabolism (body chemistry) metabolism (body chemistry)

present at birth that results in physical or present at birth that results in physical or mental disabilities or deathmental disabilities or death

leading cause of death in the first year of lifeleading cause of death in the first year of life

Causes of Birth DefectsCauses of Birth Defects

GeneticGenetic– Single-gene defectSingle-gene defect

Achondroplasia (a form of dwarfism) Achondroplasia (a form of dwarfism) Marfan syndrome (a connective-tissue disease)Marfan syndrome (a connective-tissue disease) Tay-Sachs disease (a fatal nervous system disorder) Tay-Sachs disease (a fatal nervous system disorder) Cystic fibrosis (a serious disorder of lungs and other Cystic fibrosis (a serious disorder of lungs and other

organs, affecting mainly Caucasians)organs, affecting mainly Caucasians) Hemophilia (a blood-clotting disorder) Hemophilia (a blood-clotting disorder) Duchenne muscular dystrophy (progressive muscle Duchenne muscular dystrophy (progressive muscle

weakness)weakness)

AchrondoplasiaAchrondoplasia

Marfan SyndromeMarfan Syndrome

Marfan SyndromeMarfan Syndrome

Tay Sachs DiseaseTay Sachs Disease

Cystic FibrosisCystic Fibrosis

Cystic FibrosisCystic Fibrosis

HemophiliaHemophilia

Duchenne Muscular DystrophyDuchenne Muscular Dystrophy

Causes of Birth DefectsCauses of Birth Defects

GeneticGenetic– Chromosomal birth defectsChromosomal birth defects

Down syndrome (trisomy 21)Down syndrome (trisomy 21) Trisomies 18 and 13 Trisomies 18 and 13 Sex chromosome abnormalities Sex chromosome abnormalities

– Turner syndrome (girl is missing all or part of an X Turner syndrome (girl is missing all or part of an X chromosome) chromosome)

– Klinefelter syndrome (boy has one or more extra X Klinefelter syndrome (boy has one or more extra X chromosomes).chromosomes).

Down Syndrome(Trisomy 21)

Edwards SyndromeTrisomy 18

Patau SyndromeTrisomy 13

Turner Syndrome (X)

Klinefelter Syndrome (Xxy)

Causes of Birth DefectsCauses of Birth Defects

GeneticGenetic– Multifactorial birth defectsMultifactorial birth defects

Cleft lip/palate (opening in the lip and/or roof of the Cleft lip/palate (opening in the lip and/or roof of the mouth) mouth)

Neural tube defects (NTDs) (serious birth defects of Neural tube defects (NTDs) (serious birth defects of the brain and spinal cord, including spina bifida and the brain and spinal cord, including spina bifida and anencephaly) anencephaly)

Heart defectsHeart defects

AnencephalyAnencephaly

Causes:Causes: 1) Folic acid defiency 1) Folic acid defiency

– caused by poor or inadequate dietcaused by poor or inadequate diet– SmokingSmoking– alcohol usealcohol use– PsorasisPsorasis– birth-control pill use)birth-control pill use)

2) Undiagnosed diabetes 2) Undiagnosed diabetes 3) Hypervitaminosis A 3) Hypervitaminosis A

AnencephalyAnencephaly

4) High temperatures of 102 degress or 4) High temperatures of 102 degress or higher for more than 5 hourshigher for more than 5 hours

6) Anticonvulsant medication, 6) Anticonvulsant medication, especially Valporic acidespecially Valporic acid

7) Environmental/chemical 7) Environmental/chemical exposureexposure

8) Rare genetic cause8) Rare genetic cause

Cleft lip/ palateCleft lip/ palate

Spina BifidaSpina Bifida

Club footClub foot

HydrocephalusHydrocephalus

Causes of Birth DefectsCauses of Birth Defects

TeratogensTeratogens– Any agent that can disturb the development of Any agent that can disturb the development of

an embryo or fetus. an embryo or fetus. – may cause a birth defect in the childmay cause a birth defect in the child– may halt the pregnancy outrightmay halt the pregnancy outright

Path of TeratogenPath of Teratogen

DrugsDrugs

Acne medication (isotretinoin): pregnancy Acne medication (isotretinoin): pregnancy loss, hydrocephalus, small or absent loss, hydrocephalus, small or absent thymus, microtia (abnormally small ear), thymus, microtia (abnormally small ear), anotia (absence of ear), conotruncal heart anotia (absence of ear), conotruncal heart defects)defects)

AlcoholAlcohol

Fetal Alcohol SyndromeFetal Alcohol Syndrome

DrugsDrugs

Antibiotics: Antibiotics: – Tetracyline: stained teeth, enamel hypoplasia Tetracyline: stained teeth, enamel hypoplasia

[incomplete or defective development][incomplete or defective development]– DoxycyclineDoxycycline– Streptomycin: hearing lossStreptomycin: hearing loss

CaffeineCaffeine Cigarette smokingCigarette smoking Illegal drugsIllegal drugs

CaffeineCaffeine

stimulant found in colas, coffee, tea, soft stimulant found in colas, coffee, tea, soft candies, chocolate, cocoa, and candies, chocolate, cocoa, and over-the-counter and prescription drugsover-the-counter and prescription drugs

lower birth weight for infantslower birth weight for infants and a and a lower lower concentration of iron in mothersconcentration of iron in mothers

may also contribute to may also contribute to maternal and infant maternal and infant anemiaanemia..

SmokingSmoking

miscarriage, stillbirth, placental miscarriage, stillbirth, placental problems, bleeding during pregnancy problems, bleeding during pregnancy and premature birthand premature birth. .

Babies practice breathing movements while Babies practice breathing movements while in the womb. It has been shown in the womb. It has been shown that cigarette smoking can disrupt these that cigarette smoking can disrupt these breathing movements. breathing movements.

SmokingSmoking

Research has also shown that babies of Research has also shown that babies of smokers are generally smokers are generally below the average below the average birth weight and that these babies can birth weight and that these babies can develop complications such develop complications such as infections and breathing problems as infections and breathing problems during the first weeks of life. during the first weeks of life.

Some research has indicated that Some research has indicated that smoking may increase the risk of smoking may increase the risk of sudden infant death syndrome.sudden infant death syndrome.

DrugsDrugs

Organic mercuryOrganic mercury Thalidomide: limb reduction, ear anomaliesThalidomide: limb reduction, ear anomalies Tranquilizers: cleft palate, other congenital Tranquilizers: cleft palate, other congenital

malformationsmalformations Others: anti-cancer drugs, anti-depressant, Others: anti-cancer drugs, anti-depressant,

anti-manic drug, anti-rheumatic agent, anti-anti-manic drug, anti-rheumatic agent, anti-thyroid drugs, blood thinner, seizure thyroid drugs, blood thinner, seizure medicationmedication

ThalidomideThalidomide

was commonly used was commonly used by pregnant women to by pregnant women to combat morning combat morning sicknesssickness

stunted arms and legs stunted arms and legs in babiesin babies

Maternal Disorder

Hypertension: Hypertension: intrauterine growth retardationintrauterine growth retardation Hyper/ hypothyroidism: Hyper/ hypothyroidism: goiter, growth and developmental goiter, growth and developmental

retardationretardation insulin dependent diabetes mellitus: insulin dependent diabetes mellitus: congenital heart congenital heart

defects, caudal deficiency, neural tube defects, limb defects, caudal deficiency, neural tube defects, limb defects, holoprosencephaly [facial defects that occurred defects, holoprosencephaly [facial defects that occurred during fetal development], pregnancy lossduring fetal development], pregnancy loss

Phenylketonuria: Phenylketonuria: pregnancy loss, microcephaly, mental pregnancy loss, microcephaly, mental retardation, facial dysmorphism, congenital heart defects)retardation, facial dysmorphism, congenital heart defects)

Maternal Infections

Toxoplasmosis Other agents: parvovirus B-19, syphillis, Venezuelan

equine encephalitis Rubella (German measles) Cytomegalovirus (CMV) Herpes Virus german measles, gonorrhea, and herpes – produce

abnormalitiesdiptheria, meningitis, scarlet fever, whooping cough, and pneumonia – may leave permanent damage to the central nervous systemdiabetes- fetus grows abnormally large, making delivery more difficult

Toxoplasmosis

ToxoplasmosisToxoplasmosis

STIsSTIs

Syphilis: Syphilis: abnormal teeth and bones, mental abnormal teeth and bones, mental retardationretardation

AIDS Dysmorphic Syndrome or HIV AIDS Dysmorphic Syndrome or HIV Embyopathy: Embyopathy: facial malformations, an facial malformations, an unusually small head, and growth unusually small head, and growth deficiency deficiency

HerpesHerpes

Congenital Varicella SyndromeCongenital Varicella Syndrome

low birth weightlow birth weight and and characteristic characteristic abnormalities of the skin; the arms, legs, abnormalities of the skin; the arms, legs, hands, and/or feet (extremities); the hands, and/or feet (extremities); the brain; the eyes; and/or, in rare cases, brain; the eyes; and/or, in rare cases, other areas of the body.other areas of the body.

newborns with Congenital Varicella newborns with Congenital Varicella Syndrome may have Syndrome may have additional additional abnormalities associated with abnormalities associated with the disorder.the disorder.

RubellaRubella

glaucoma, microphthalmia, cataracts, glaucoma, microphthalmia, cataracts, cardiac malformation, hearing loss and cardiac malformation, hearing loss and mental retardation. Together, these mental retardation. Together, these malformations constitute congenital rubella malformations constitute congenital rubella syndromesyndrome

Cytomeglovirus (CMV)Cytomeglovirus (CMV)

blindness, deafness, cerebral palsy and blindness, deafness, cerebral palsy and mental retardationmental retardation

Environment Chemicals

Lead: Lead: pregnancy loss, central nervous pregnancy loss, central nervous system damagesystem damage

methylmercury methylmercury (chemical found in some (chemical found in some seafood): seafood): cerebral atrophy, spasticity, cerebral atrophy, spasticity, mental retardationmental retardation

Radiation: Radiation: growth and developmental growth and developmental retardation,microcephalyretardation,microcephaly

Baby with birth defects Baby with birth defects attributable to pesticides (PBP)attributable to pesticides (PBP)

Bucky Bailey was Bucky Bailey was born with only born with only one nostril and a one nostril and a deformed right deformed right eye. His mother eye. His mother worked in theworked in theDuPont plant in DuPont plant in Parkersburg, Parkersburg, W.Va where she W.Va where she mixed the mixed the chemicals for chemicals for Teflon, when she Teflon, when she becamebecamepregnant.pregnant.

Insulin-dependent diabetes has been linked Insulin-dependent diabetes has been linked to multiple congenital malformations such as to multiple congenital malformations such as cardiac and skeletal (appendicular and cardiac and skeletal (appendicular and axial) malformations, central nervous axial) malformations, central nervous system alterations (holoprosencephaly) and system alterations (holoprosencephaly) and caudal dysgenesis (agenesis of sacral caudal dysgenesis (agenesis of sacral vertebrae and hind limb hypoplasia)vertebrae and hind limb hypoplasia)

Metabolic Birth DefectsMetabolic Birth Defects

Newborn Screeningdone at birthPositive for Congenital HypothyroidismTreated immediatelyNormal 7-year old girl

Newborn Screeningnot done at birthPositive for Congenital HypothyroidismNo physical signs at birthNot treated immediately14-year old retarded boy

Affected babies cannot process a part of protein, which builds up and damages the brain.

Babies with this disorder have a hormone deficiency that slows Babies with this disorder have a hormone deficiency that slows growth and brain development.growth and brain development.

Affected babies cannot process galactose (a sugar in milk), which builds up and can lead to mental retardation, blindness and death.

Babies who have this group of disorders are deficient in certain Babies who have this group of disorders are deficient in certain hormones produced by the adrenal gland. CAH affects genital hormones produced by the adrenal gland. CAH affects genital development and, in severe cases, can disturb kidney function and development and, in severe cases, can disturb kidney function and cause death. cause death.

G6PD DEFICIENCYG6PD DEFICIENCY

X-linked recessive hereditary disease characterized by abnormally low X-linked recessive hereditary disease characterized by abnormally low levels of the glucose-6-phosphate dehydrogenase enzyme levels of the glucose-6-phosphate dehydrogenase enzyme (abbreviated G6PD or G6PDH). It is a metabolic enzyme involved in (abbreviated G6PD or G6PDH). It is a metabolic enzyme involved in the pentose phosphate pathway, especially important in red blood cell the pentose phosphate pathway, especially important in red blood cell metabolism.metabolism.

Sickle cell disease is an inherited blood disease in which red blood cells stretch into Sickle cell disease is an inherited blood disease in which red blood cells stretch into abnormal "sickle" shapes and can cause episodes of pain, damage to vital organs abnormal "sickle" shapes and can cause episodes of pain, damage to vital organs such as the lungs and kidneys, and even death. Young children with sickle cell such as the lungs and kidneys, and even death. Young children with sickle cell disease are especially prone to certain dangerous bacterial infections, such as disease are especially prone to certain dangerous bacterial infections, such as pneumonia (inflammation of the lungs) and meningitis (inflammation of the brain and pneumonia (inflammation of the lungs) and meningitis (inflammation of the brain and spinal cord).spinal cord).

Babies with this condition don't have enough biotinidase, an enzyme Babies with this condition don't have enough biotinidase, an enzyme that recycles biotin (one of the B vitamins) in the body. The deficiency that recycles biotin (one of the B vitamins) in the body. The deficiency may cause seizures, poor muscle control, immune system may cause seizures, poor muscle control, immune system impairment, hearing loss, mental retardation, coma, and even death. impairment, hearing loss, mental retardation, coma, and even death.

This metabolic disorder results from a deficiency of one of several This metabolic disorder results from a deficiency of one of several enzymes for normal development. If untreated, it can lead to enzymes for normal development. If untreated, it can lead to dislocated lenses of the eyes, mental retardation, skeletal dislocated lenses of the eyes, mental retardation, skeletal abnormalities, and abnormal blood clotting. abnormalities, and abnormal blood clotting.

Babies with MSUD are missing an enzyme needed to process three amino acids that Babies with MSUD are missing an enzyme needed to process three amino acids that are essential for the body's normal growth. When these are not processed properly, are essential for the body's normal growth. When these are not processed properly, they can build up in the body, causing urine to smell like maple syrup or sweet, burnt they can build up in the body, causing urine to smell like maple syrup or sweet, burnt sugar. These babies usually have little appetite and are extremely irritable. If not sugar. These babies usually have little appetite and are extremely irritable. If not detected and treated early, MSUD can cause mental retardation, physical disability, detected and treated early, MSUD can cause mental retardation, physical disability, and even death.and even death.

Babies with this disorder have trouble processing the amino acid Babies with this disorder have trouble processing the amino acid tyrosine. If it accumulates in the body, it can cause mild retardation, tyrosine. If it accumulates in the body, it can cause mild retardation, language skill difficulties, liver problems, and even death from liver language skill difficulties, liver problems, and even death from liver failure. failure.

Rh Factor

Rh factor – caused by genetic incompatibility between mother (Rh-) and child (Rh+)

Rh- - may produce antibodies that can destroy the baby’s blood system

Causing hemolytic disease of the newbornCausing hemolytic disease of the newborn– can lead to brain damage, mental retardation, can lead to brain damage, mental retardation,

and even death.and even death.

Mother’s emotions – maternal anxiety or anger may cause various hormones to be released in the mother’s blood, which may be absorbed by the fetal blood stream- can produce cleft palate and harelip and mental retardation

Mother’s age Prior abortion

Reproductive choicesReproductive choices

Genetic counselingGenetic counseling Prenatal diagnostic methods:Prenatal diagnostic methods:

– AmniocentesisAmniocentesis– Chorionic villus samplingChorionic villus sampling– FetoscopyFetoscopy– UltrasoundUltrasound– Maternal blood analysisMaternal blood analysis– Preimplantation genetic diagnosisPreimplantation genetic diagnosis

Prenatal testing techniquesPrenatal testing techniques