Structural Abnormalities and Birth Defects Flashcards
Structural or functional abnormality in development present at birth.
Congenital anomaly (birth defect)
Irregular, anomalous, abnormal, or faulty formation or structure.
Malformation
Resulting from maternal mechanical factors
Congenital deformation
Resulting from abnormal embryologic development, usually genetic.
Congenital malformation
Chromosomal
Congenital disorders
Birth trauma
Specific birth defects
Causes of abnormalities
Hereditary factors received from ancestors passed genetically to offspring. Form strand of DNA and associated proteins in the nucleus of eukaryotic cells. Composed of thousands of genes located at specific positions within this, function in the transmission of hereditary information.
Chromosomes
How many chromosomes does each individual have?
46 (23 pairs)
Determine body functions and appearance (eye and hair color, for example). There are 22 pairs of these (44 total).
Autosomal Chromosomes
Determine the sex of an individual. There are 2 of these (1 pair).
females- XX
makes- XY
Sex Chromosomes
True or false?
All somatic (body) cells have 46 chromosomes; reproduce by mitosis; divide into identical daughter cells, each with 46 chromosomes.
True
These cells have 46 chromosomes; reproduce by meiosis, and result in gametes.
Ovum- 23 chromosomes
Sperm- 23 chromosomes
Germ (sex) cells
Formed by pairing of genes
Alleles
Both genes are dominant, or both genes are recessive.
Homozygous alleles
One gene is dominant, the other is recessive
Heterozygous alleles
Too few chromosomes present.
Monosomy
Too many chromosomes present.
Trisomy
Lacking one X chromosome (44 autosomes and one X chromosome) and is clinically a female. Have a short, broad chest with underdeveloped breasts, cardiac malformations, ovaries, uterus. Sexually immature, infertile, and mental retardation is common (but with hormone replacement, normal intelligence and life).
Turner’s Syndrome
2X plus 1Y chromosome (too many sex chromosomes), is clinically a male. Usually sterile, underdeveloped prostate, testes, no facial hair, enlarged breasts, large hands and feet, long arms and legs.
Klinefelter’s Syndrome
Trisomy 21, three copies of chromosome 21 (too many autosomes)
mental retardation, short and curved 5th finger, characteristic facial appearance (flat nasal bridge, low-set ears, slanted eyes, heart defects).
Down’s Syndrome
Trisomy 18 - three copies of chromosome 18 (too many autosomes)
usually fatal within 3 months due to multiple congenital defects, cleft lip and palate, severe mental and motor retardation.
Edward’s syndrome
Trisomy 13- three copies of chromosome 13 (too many autosomes)
physical abnormalities: microcephaly, polydactyly, syndactyly, heart defects
generally death in infancy
Patau Syndrome
Anything that adversely affects normal cellular development in the embryo or fetus, can damage fetal or ovarian DNA inducing congenital fetal malformation.
examples: infectious agents, radiation and other factors
Teratogen
group of symptoms and birth defects in infants born to mother who consumed alcohol/narcotics during pregnancy.
includes mental challenges, decreased physical development, hyperactivity, microcephaly
Fetal alcohol/ fetal narcotic syndrome
group of infections acquired by women during pregnancy and transmitted to the child in the womb. 3-9 week of pregnancy exposure may result in the baby’s death or serious complications.
TORCH teratogens
TO-xoplasmosis
R-ubella (german measles)
C-ytomegalovirus (CMV)
H-erpes virus
TORCH teratogens
Rubella virus crosses the placenta to the fetus, causes microcephaly, learning disorders, deafness, and heart defects.
Congenital rubella syndrome
radiation
nutritional deficiencies
condition of the mother (age, fluid retention and poor diet, hormonal imbalance, physical injury, maternal radiation, infection, metabolic disorders, drugs and medications)
Etiology of congenital disorders
Physical or psychological injury sustained by an infant during birth
-infections (gonorrhea, herpes in birth canal),
physical trauma, lack of oxygen, umbilical cord strangulation
Birth Trauma
Grossly deformed fetus
-conjoined twins, parasitized fetus
Monsters
Abnormal development of epiphyseal cartilage
- rare, short statue, disproportionately short arms and legs, large head and characteristic facial features
- 80% have two parents of average height
Achondroplasia (hereditary dwarfism)
Due to hypopituitarism (hyposecretion of growth hormone)
-4’ tall with normal body proportions, normal intelligence
Pituitary dwarfism
Hypersecretion of growth hormone, enlarged bones of skull, arms and legs
Hyperpituitarism
In children, up to 8’ tall, normal body proportions, slower sexual development, mental development normal or retarded.
Giantism
After closure of epiphyseal plate, thickening of soft tissue- enlarged lips, nose, tongue, thicker skin. May lead to congestive heart failure, respiratory or cerebrovascular problems.
Acromegaly
A condition of having more than normal number of fingers or toes.
Polydactylism
A condition of having two or more fused fingers or toes.
Syndactylism
Absence of fingers and/or toes.
Adactylism
Congenital condition in which the proximal portions of the limbs are poorly developed or absent.
-Hands and/or feet are attached to the trunk directly
Phocomelia
Congenital absence of one more more limbs.
Amelia
Deformity of foot (bent inward); over calcification of bones of the foot; possibly genetic factors or fetal position.
Clubfoot
Abnormality of hip joint; easy fractures due to hip dysplasia; caused by improper fetal or during birth position or maternal hormones; difference in leg length or asymmetrical folds on the affected thigh.
Dislocated hip
Two sides of the palate fail to fuse during fetal development; results in opening (fissure) between palatine bones (roof of mouth).
separate or in combination with cleft lip, related to hereditary factors, repaired surgically, more common in girls.
Cleft palate
Separation of the two sides of the lip, may include bones of the upper jaw.
-related to hereditary factors, repaired surgically
Cleft lip
Short frenulum under the tongue; cause restriction of tongue motion > speech difficulty.
Tongue tie
Closed sac in or under the skin containing fluid or semisolid mass.
Cyst
Abnormal passage from internal organ to body surface or between two internal organs.
Fistula
Connection between esophagus and trachea; life threatening.
Tracheo- esophageal fistula
Fatal genetic disease (autosomal recessive) with defective transport of chloride.
Affects exocrine glands causing secretion of thick mucous that obstructs body passageways (lungs and pancreas).
Respiratory and digestive cystic fibrosis
Congenital deafness that results in inability to speak.
Deaf mutism
Absence of or defect in the perception of colors.
- sex linked recessive trait, usually in males.
Color blindness
Eyes of different colors due to excess or lack of pigment within an iris; sex-linked.
Heterochromia
Nearsightedness, longer eyeball, distant objects appear blurred.
Myopia
Farsightedness, shorter eyeball, near objects appear blurred.
Hyperopia
Clouded lens usually due to infection in utero.
Cataract
Areas of excess melanin; usually more prominent when exposed to light.
Freckles
Congenital vascular tumor (overgrowth of superficial blood vessels); usually on face, head, neck, arms.
Vascular nevus (birthmark= strawberry mark)
Fish scale appearance with thickened overlapping skin layers.
Ichthyosis
Excessive growth of terminal hair in areas not normally hairy; usually due to certain drugs (corticosteroids, diazoxide, minoxidil)
Hypertrichosis
Less than normal amount of hair on head or body; due to hereditary hair follicle dysplasia, inflammation of infection of hair follicles, neoplastic destruction, irradiation.
Hypotrichosis
Accessory nipples if the breast or elsewhere, cause unknown.
Polythelia
More than two breast are present.
Polymastia
Absence of breasts.
Amastia
Failure of the skull bones to close.
no neural groove > no brain (anencephaly) or spinal cord; probably congenital.
Cranioschisis
Abnormally small head and brain. Usually results in mental retardation, probably genetic.
Microcephaly
Congenital absence of the brain (defect in development of the brain); absence of major portions of the brain (and spinal cord). The bones of the skull fail to develop > exposed brain is destroyed in the utero, infant will be stillborn or die shortly after birth.
Anencephaly
Abnormal accumulation of cerebrospinal fluid in the ventricles of the brain. Results in swelling of the brain, caused by injury, infection, or disease.
Hydrocephalus
Neural tube defect, one or more vertebrae fail to fuse (usually in the lumbar area)> leaving opening or weakness in vertebral column.
possible causes: radiation, virus, genetic factors, folic acid deficiency.
Spina bifida
Syndrome of four related defects of the heart and aorta, most commonly seen with intraventricular septal defect. Caused by fetal alcohol syndrome or thalidomide use during pregnancy.
1- narrowing of the pulmonary valve
2- thickening of the right ventricular wall
3- displacement of the aorta
4- ventricular septal defect
Tetralogy of fallout
No heart forms.
Acardia
Malposition of the heart; projects outside the ribcage.
Ectopia cordis
Heart is on the right side of the chest.
Dextrocardia
Underdevelopment of tissue, or organ of the body. Could be due to maternal diabetes or alcohol abuse.
Hypoplasia
Failure of tissue or organ to develop normally.
Aplasia
Two horns to the uterus (essentially two uteri)
Bicornuate uterus
Containing both ovaries and testes.
Hermaphrodism (hermaphoditism)
Congenital absence of closure of normal body opening.
Atresia
Esophagus does not join the stomach
Esophageal atresia
Narrowing of a passage
Stenosis
Narrowing of larynx with possible blockage
Laryngeal stenosis
Narrowing of pyloric valve, most common in first born male.
Pyloric stenosis
In males, bladder drops and urethra opens at the back of the penis.
Hypospadia
