Congenital and Genetic Diseases Flashcards
(29 cards)
Congenital deformations
result from mechanicl forces (small uterus, large fetus, compression of the fetus - oligohydramnios) (i.e., positions of feet)
Congenital malformations
result from intrinsically abnormal developmental process (i.e., spina bifida, congenital heart disease, Polydactylyl)
Congenital disruptions
result from breakdown of a normal developmental process (limb amputation due to amniotic band)
What is a syndrome?
A characteristic association of several anomalies.
What is Potter Syndrome?
Combination of both malformations and deformations. Typically abnormal kidney development leading to decreased amniotic fluid and compression of fetus. This can cause pulmonary hypoplasia and death due to respiratory insufficiency.
What are teratogens?
Agents that produce congenital malformations.
Congenital infections with teratogenic effects include:
Germal measles, cytomegalovirus, varicella zoster (chicken pox)
Drugs/chemicals with teratogenic effects include:
Thalidomide/Alcohol
Materal disorders that cause teratogenic effects include:
Diabete mellitus
Ionizing radiation that cause teratogenic effects include:
Increased incidence of microcephaly and mental retardation.
What is the mechanism of congenital rubella (german measles)?
If the mother gets rubella w/I the 1st trimester, fetus will be infected and will inappopriately divide; end result is growth retardation, cataracts, deafness, and congenital heart diesease.
Wha is the mechanism of thalidomide?
Used to relief of nausea during pregnancy, it interferes with proper lib growth during the 3rd and 5th week post-conception. End result is phocomelia (seal limbs).
What is the effect of alcohol as a teratogen?
Fetal-alcohol syndrome (most common cause of mental retardation in the Western world): Pre/post-natal growth retardation, mental retardation, joint anomalies, heart deficitis, abnormal facscies.
Why is diabetes dangerous for fetuses?
Risk for malformation is 6%, can be upto 20%. Insulin-dependent is most dangeorus. Sympoms include: malformations in kidney, heart, and brain.
What are the different types of chromosomal disorders?
Numerical, sex, and structural
Autosomal chromosome numerical abnormalities
Autosomal include Trisomy 21 and Down Syndrome; More dangerous than sex (abnormal fascies, palmar creases, congenital diseases, duodenal stenosis or atresia, and mental retardation). Significant with advanced maternal age.
Sex chromosome numerical abnormalities
Sex include Turner Syndrome (XO) and Klinefelter Syndrome (XXY); result in loss of 2nd sexual characteristics and infertility.
Structural chromosomal abnormalities
Deletion of parts of chromosomes; Cri-du-chat (partial deletion of ch5 - causes cat-like cry in infancy, small head and facial abnormalities).
Three types of single-gene disorders
Autosomal dominant, autosomal recessive, X-linked recessive
Characteristics and examples of autosomal dominant disorders:
(1) at least one parent has the disease, (2) 50% risk to children, and (3) both sexes are equally affected. Example include marfan syndrome and familiar hypercholesterolemia.
What is marfan syndrome?
On chromosome 5, error in connective tissue. Long limbs, dislocation of lens and eye and dilation of aorta.
What is familiar hypercholesterolemia?
On chromosome 19, very common and leading cause of coronary heart disease. Defect in LDL receptor, thus elevated cholesterol in plasma and deposition of cholesterol in arteries. Fatal in childhood (1/1000000).
Characteristics and examples of autosomal recessive disorders:
(1) both parents are normal, but carriers, (2) 25% risk to children, (3) both sexes are equally affected; Diseases include CF and phenylketonuria (PKU).
What is CF (cystic fibrosis)?
On ch7, most common auto-rec disease in caucasian children (1/1600); carriers are 1/20 incidence. Respiratory tree mucous is abnormal causing repeated infection, in addition to intestinal inabsorption due to lack of pancreatic secretion..
