Prenatal Development
Prenatal or antenatal development is the process in which a human
embryo or fetus gestates during pregnancy, from fertilization until birth.
Genetic disorders during prenatal development:
Genetic disorders are physical defects or illnesses that are caused by
problems in body's genetic code.
Genetic disorders are responsible for one third of all birth defects.
Genetic disorders may be grouped within three groups:
Chromosome number abnormalities
Chromosome structure abnormalities
Gene mutations
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Chromosome number abnormalities: Monosomy
45 XO Turner’s syndrome
Trisomy
Klinefelter syndrome
Edward’s syndrome
Down’s syndrome
Tetrasomy
Pentasomy
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Chromosome Structure Abnormalities: Mosaicism
Translocation
Chromosome deletion
Microdeletion
Prader-villi Syndrome
Prader-villi syndrome Translocation Microdeletion
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Gene Mutation
Autosomal dominant
inheritance:
Achondroplasia
Ectrodactly
Polydactyly
Osteogenesis Imperfecta
Osteogenesis imperfecta Achondroplasia
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Autosomal recessive inheritance
Cystic fibrosis
Childhood spinal muscular atrophy
Tay-sachs disease
Phenylketonuria (PKU)
Tay-sachs disease
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X-linked inheritance
Rett Syndrome-
Hemophilia
Duchenne’s muscular
dystrophy
Fragile X Syndrome
Other genetic disorders:
Sickle cell anemia
Thalessemia
spinabifida
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Causes
Teratogens
Maternal diseases:
• Rubella- blindness, deafness, brain damage
• Chicken pox and mumps- birth defects, miscarriage
• Syphilis and gonorrhea- transmitted to child
• AIDS- small mishappen face, protruding lips, brain deterioration
• Herpes Virus- deafness, brain swelling, mental retardation
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Causes
Maternal drug use:
aspirin can lead to bleeding
thalidomide caused missing limbs
marijuana restricts oxygen to the fetus
methamphetamine is linked to low birth weight and neurological impairment.
cocaine restricts blood flow and oxygen.
Both alcohol and cigarettes can disrupt the development of the fetus,
FETAL ALCOHOL SYNDROME (FAS) is a disorder caused by the pregnant mother consuming substantial quantities of alcohol during pregnancy potentially resulting in mental retardation, delayed growth, and facial deformities.
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Prevention
Vaccination
Folic acid dosage
Avoid unnecessary medicines
don't smoke
don't drink alcohol
avoid all illicit drugs
get exercise and plenty of rest
get early and regular prenatal care
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Diagnosis
Genetic counseling
Prenatal testing
Ultrasound: 6-10, 16-20 weeks
Amniocentesis: 16-20 weeks
Chorionic villus sampling:
10-12 weeks
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