CONGENITAL
&
HEREDITARY DISEASES
What is congenital disease?
any abnormality present at birth
may not be detected at birth
maybe genetic, environmental or both
type
major
create significant medical problems for the patient
intrinsic defects of development
e.g. mistakes in the genome
majority of congenital diseases
extrinsic
e.g. Fetal disruptions
oligohydramnios (lack of amniotic fluid)
fetal deformation due to compression or mispositioning
minor
cosmetics significance
>10% live birth
examples
Cleft Lip
Polydactyly
Pre
Thumb
Post
Pinky finger
Central
Any other fingers
Objectives
Describe examples of intrauterine malformations and its common causes
Describe the role of chromosome abnormalities in congenital disease.
List the causes of Down syndrome and describe its clinical manifestations.
Describe common genetic abnormalities and their methods of transmission.
List abnormalities of sex chromosomes and describe their clinical manifestations.
Understand the methods for diagnosing congenital abnormality.
Intrauterine Injury
what?
injury to the developing embryo
intra = within
uterine = uterus
3rd - 8th week after conception
most vulnerable to injurious effects of environmental agents
common causes
Drugs and Chemicals
FDA "Degree of Possible Risk to the Fetus"
Cat A
No risk to fetus in well-controlled studies in humans.
Cat B
No risk to fetus based on animal studies
no adequate human studies
Cat C
Risk to fetus cannot be ruled out
No human studies available to assess risk
Cat D
Positive evidence of risk to fetus
No safer alternative drug is available
Potential benefit to patients outweighs
risk to fetus
Cat X
Absolutely contraindicated in pregnancy
Severe risk to fetus greatly outweighs
any possible benefit to patients
Cigarettes
causes
Intrauterine growth retardation (IUGR)
birth of smaller than normal infants
premature births
sudden infant death syndrome (SIDS)
unexplained death of a child under the age of one year
Decrease amount of oxygen to the baby
Drugs
Narcotics usage such as heroin, methadone, cocaine, codeine, morphine etc
Many new drugs/antibiotics have unknown possible effects
causes
addiction in both the fetus and the mother
Impaired fetal growth
Neonatal abstinence syndrome (NAS)
Intrauterine fetal demise (IUFD)
disturb blood flow through the placenta causing fetal death
Alcoholic beverages
causes
fetal alcohol syndrome
physical and mental retardation
abnormal cranial and facial development
congenital malformations affecting the genital tract and cardiovascular system
severe drinking problem
should be cautioned not to become pregnant until their alcoholism is controlled
the level of alcohol consumption that puts a
fetus at risk is controversial
Radiation
exposure of a pregnant woman may harm the fetus
vulnerable especially the first fifteen weeks of fetal development
an increased rate of development of childhood leukemia
fetuses with an age greater than fifteen weeks have a lower radiation sensitivity
causes
Fetus with stunted growth
Fetal abnormalities
Abnormal brain function
Increase chance of cancer in later life
Maternal infections
TORCH complex
Toxoplasmosis
What?
a parasitic infection caused by Toxoplasma gondii
Young women show low rates of immunity
infection during pregnancy is a major risk factor
How?
feces of infected animals
eating raw or partially cooked meat infected with the parasite
Causes
congenital blindness
congenital epilepsy
encephalitis — inflammatory disorder of brain
Others
herpes simplex virus
What?
a sexually transmitted infection
How?
transmitted from infected mother to fetus
Causes
skin and eye lesions
microcephaly
intrauterine fetal death
baby died inside uterus before birth
intrauterine fetal anemia
amount of red blood cells in a fetus fall below normal levels.
infant mortality
death of an infant before the first birthday
Rubella
What?
a mild illness acquired in childhood
How?
Rubella virus (Rubivirus rubellae)
Causes
congenital cataracts
congenital cardiac malformations
defects or anomalies of the heart since birth
congenital deafness
loss of hearing at birth or may develop later
neurological disturbances
chronic progressive infection
infection progress faster than normal
Cytomegalic Inclusion Disease (CID)
What
an infection that is largely asymptomatic
How
caused by cytomegalovirus affecting a pregnant or immune weakened individual
Causes
microcephaly
mental retardation
blindness
injury to the fetal brain and eyes
HIV
What
a virus that attacks the body's immune system
How
Vertical transmission of human immunodeficiency virus (HIV) from the infected mother to the child
before birth
after birth
breastfeeding
Causes
Babies with weakened immune system
can get infections and certain types of cancer that a healthy babies would normally be able to fight off.