This document discusses genetic disorders that can occur during prenatal development. It notes that genetic disorders are caused by problems in the genetic code and are responsible for one-third of all birth defects. Genetic disorders are grouped into three categories: chromosome number abnormalities, chromosome structure abnormalities, and gene mutations. Some examples of specific genetic disorders are discussed for each category, along with potential causes during prenatal development like maternal diseases, drug use, and teratogens. The document concludes with sections on prevention of genetic disorders and diagnosis of potential issues during prenatal testing.

1. Genetic Disorders during
Prenatal Development
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2. 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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3. Chromosome number abnormalities:
 Monosomy
 45 XO Turner’s syndrome
 Trisomy
 Klinefelter syndrome
 Edward’s syndrome
 Down’s syndrome
 Tetrasomy
 Pentasomy
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4. Chromosome Structure Abnormalities:
 Mosaicism
 Translocation
 Chromosome deletion
 Microdeletion
 Prader-villi Syndrome
Prader-villi syndrome Translocation Microdeletion
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5. Gene Mutation
 Autosomal dominant
inheritance:
 Achondroplasia
 Ectrodactly
 Polydactyly
 Osteogenesis Imperfecta
Osteogenesis imperfecta Achondroplasia
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6. Autosomal recessive inheritance
 Cystic fibrosis
 Childhood spinal muscular atrophy
 Tay-sachs disease
 Phenylketonuria (PKU)
Tay-sachs disease
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7. 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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8. 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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9. 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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10. 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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11. 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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