Triple X Syndrome
Turner Syndrome
Turner syndrome is a result of an X chromosome abnormality. The frequency is approximately 1 in 2500, but only represents births in which the embryo is not spontaneously aborted (occurring in most embryos lacking an X chromosome). Characteristics include short stature, broad neck and chest, lack of breast development, widely spaced nipples, small uterus, dysfunctional ovaries and cardiovascular abnormalities. (Crowley, 2014)
Triple X syndrome is the presence of an additional X chromosome in the cells of a female and has an incidence of 1 in 850 female births. The syndrome usually results in no specific abnormalities because the extra X chromosome remains inactivated. Sexual development is usually normal, but fertility and inteligence may be decreased. (Crowley, 2014)
XYY Syndrome is a chromosomal abnormality with an incidence of 1 in 850 male births. Symptoms present as reduction of fertility and intelligence. Individuals who suffer from this syndrome are usually taller than normal, but have no abnormal body configuration. (Crowley, 2014)
Klinefelter syndrome occurs in approximately 1 in 750 male births and is the presence of an extra X chromosome in males. Symptoms present as atrophic testicles, inability to produced spermatozoa, and sterility. The figure will be slightly feminine with possible breast hypertrophy. The individual may also suffer from subnormal intelligence. (Crowley, 2014)
XYY Syndrome
Klinefelter Syndrome
Congenital and Hereditary Diseases
A hereditary disease is one defined as a disease resulting from a chromosome abnormality or a defective gene.
A congenital disease or malformation is any abnormality that is present at birth, although it may not be detected until some time after birth. Factors known to lead to congenital malformations include chromosomal abnormalities, abnormalities of individual genes, intrauterine injury to the embryo or fetus, and environmental factors acting on a genetically predisposed embryo. (Crowley, 2014)
The Fragile X Syndrome
Down Syndrome
Fragile X syndrome is second only to Down syndrome as a major cause of mental deficiency. Because the syndrome is an X linked inherited dysfunction, a woman can pass it to either son or daughter, but a man can only pass it to his daughter. The severity of the mental eficiency depends on the number of times abnormally arranged nucleotides is repeated. Fragile X syndrome can be disgnosed through DNA analysis to identify the number of CGG repeats in genetic coding. (Crowley, 2014)
Down syndrome is the most comon chromosomal abnormality, with an incidence rate of 1 in 600 births, which only represents the 30% of trisomy 21 fetuses that survive to full term. Down syndrome is caused by a trisomy (or an additional chromosome) at chromosome 21. Symptoms include mental deficiency, upward-slanting eyes, and prominent skin folds extending from the base of the nose to inner eyebrows. Cardiac malformations and congenital defects in other organ systems also frequently occur. (Crowley, 2014)
Trisomy of Chromosome 13
Rubella
An additional chromosome at chromosome 13 presents with developmental abnormalities, including cleft lip and palate, abnormal development of the skull and brain, abnormal eye development, congenital heart defects and polydactyly. This trisomy usually is fatal in the neonatal period or in early infancy.
(Crowley, 2014)
Rubella is the virus of German measles which is a mild illness with 90% of childbearing-aged women have had, or are immunized for. However, if she acquires rubella during pregnancy, the embryo may be infected, leading to spontaneous abortion or congenital malformations. This could include cataracts, cardiac malformations, deafness and neruologic disturbances. (Crowley, 2014)
Phenylketonuria
Tay-Sachs Disease
Tay-Sachs disease usually occurs in the Jewish population and is caused by the absence of a lysosomal enxyme which leads to an accumulation of the lipid ganglioside. This leads to cell dysfunction and degeneration of brain, spinal cord, automonic nervous system and retina nerve cells. The disease is characterized by mental deterioration, nerrologic dysfunction and blindness. Symptoms occur at 6 months and the disease is fatal by 3-4 years of age. Tay-Sachs disease can be diagnosed prenatally. (Crowley, 2014)
Phenylketonuria is caused by a deficiency of the enzyme phenylalanine hydroxylase, which is necessary to metabolize phenylalanine, which is an amino acid which is abundant in breast milk. Permanent mental deficiency results from disturbed phenylalanine metabolism. Phenylketonuria can be detected through a laboratory blood screening. (Crowley, 2014)
Cystic Fibrosis
Cystic fibrosis is a genetic disorder that can manifest as a type of COPD, pancreatic deficiency, urogenital dysfunction and increased electrolytes in sweat. The disease usually starts in infancy and is a mojor cause of severe chronic lung disease in children.
Signs and symptoms include bronchitis, pneumonia, respiratory failure, gallbladder disease, pancreatitis, diabetes, and nutritional deficiencies. Individuals with cystic fibrosis are also more susceptable to heat illnesses.
Treatment includes drug therapy to slow the progress of the disease and antibiotics to control pulmonary disease.
(Prentice, 2011)
Hemophilia
Hemophilia is a hereditary disease characterized by a deficiency in any number of clotting factors in the blood.
Signs and symptoms include bleeding into muscles and joints during physical exertion, which is extremely painful and eventually joints may become immobilized.
Treatment: Unfortunately there is no cure for hemophilia but concentrated clotting factors have been developed to control bleeding. Any hemophiliac who starts bleeding should be taken to the emergency room immediately. (Prentice, 2011)
Marfan syndrome is a genetic disorder that affects the body’s connective tissue. Marfan syndrome is caused by a defect (or mutation) in the gene that tells the body how to make fibrillin-1. Because connective tissue is found throughout the body, Marfan syndrome can affect many different parts of the body, but most often affects the heart, blood vessels, bones, joints, and eyes.
Signs and symptoms include aortic enlargement, long arms, legs and fingers, tall and thin body type, curved spine, chest sinks in or sticks out, flexible joints, flat feet, crowded teeth, stretch marks on the skin that are not related to weight gain or loss, severe nearsightedness (myopia), dislocated lens of the eye, detached retina, early glaucoma, early cataracts, sudden lung collapse, emphysema, asthma, and sleep apnea.
Treatment: Unfortunately there is no cure for Marfan Syndrome, but symptoms may be treated. (Prentice, 2011)