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| This glossary contains: 19186 medical terms |
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Congenital achromatopsia,
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Congenital achromatopsia,An hereditary disorder of vision characterized by a lack of cone vision (sight provided by the cone photoreceptors in the retina). People with achromatopsia (achromats) are completely or almost completely colorblind. They have poor visual acuity, and their eyes do not adapt normally to higher levels of illumination and are very light sensitive (photophobic). At higher levels of illumination, the vision of achromats decreases unless they make use of tinted lenses. In moderately bright indoor spaces or outdoors just after dawn or just before dusk, some achromats adapt to their reduced level of visual functioning without resorting to tinted lenses, by using visual strategies such as blinking, squinting, or positioning themselves in relation to the light source. Others routinely wear medium tinted lenses in such settings. In full sunlight outdoors or in very bright indoor spaces, almost all achromats use very dark tinted lenses to have a reasonable amount of vision, since their retinas do not possess the photoreceptors needed for seeing well in such settings.
RELATED TERMS--------------------------------------
Hereditary
Transmitted from parent to offspring; derived from ancestry.
Vision
The sense of sight.
Cone
One of the two light receiving retinal cells (the other is the rod) that is responsible for daylight vision (e.g., color vision, high visual acuity, bright light vision). The area of the retina that provides central or reading vision, known as the fovea, contains only cones.
Achromatopsia
Characterized by a lack of color vision with poor visual acuity, nystagmus, and sensitivity to sunlight. No treatment is available except, for example, sunglasses for the sensitivity to light.
Acuity
The highest spatial frequency rsolvable with a grating of unity contrast (i.e. the maximum possibly contrast).
SIMILAR TERMS--------------------------------------
Congenital
Present at birth.
Congenital anemia
1. Anemia at birth. 2. Synonym for Rh incompatibility.
Congenital anomaly
Something that is unusual or different at birth. A minor anomaly is defined as an unusual anatomic feature that is of no serious medical or cosmetic consequence to the patient. A minor anomaly of the feet might, for example, be curvature of the second toe so it overlaps the third toe a little.A major anomaly, by contrast, might be a cleft lip and palate, a birth defect of serious medical and cosmetic consequence to the child.
Congenital arthrogryposis
Nonprogressive congenital contractures that develop before birth and are evident at birth (congenital). The contractures are characterized by reduced mobility of many (multiple) joints. Congenital arthrogryposis is also called arthrogryposis multiplex congenita (AMC). In AMC the range of motion of the joints in the arms and legs is usually limited or fixed. Joints affected may include the shoulders, elbows, wrists and fingers and the hips, knees, ankles, and feet -- virtually any and all joints.
Congenital bilateral absence of vas deferens
A condition in males when the tubes that carry sperm from the testes (the vas deferens) fail to develop normally. The testes usually develop and function normally and the men have normal sexual performance, but sperm cannot be transported through the male reproductive system. Men with congenital bilateral absence of vas deferens are therefore infertile (unable to conceive a child). This condition is responsible for 2 to 5% of all infertility in men. Congenital bilateral absence of vas deferens is due to mutations in the CFTR gene (the cystic fibrosis transmembrane conductance regulator gene) which encodes a protein that functions as a channel across the cell membrane.
Congenital central hypoventilation syndrome
Failure from birth of central nervous system control over breathing while asleep. There are usually no breathing problems while awake. The involuntary (autonomic) control of respiration is impaired, but the voluntary control of ventilation which operates during waking hours is generally intact.
Congenital deafness
Loss of hearing present at birth.
Congenital deafness and retinitis pigmentosa
Also called Usher syndrome.) A genetic disorder characterized by hearing impairment and an eye disorder called retinitis pigmentosa in which vision worsens over time. Some people with Usher syndrome also have balance problems.
Congenital defect
A birth defect.
Congenital Defects
Problems or conditions that are present at birth.
Congenital heart disease
"A malformation of the heart or the large blood vessels near the heart. The term ""congenital"" speaks only to time, not to causation; it means ""born with"" or ""present at birth."""
Congenital heart problems
May include ventricular septal defect (a hole in the septum) and transposition of the great vessels, where the pulmonary artery and the aorta are reversed. May be corrected with surgery soon after birth, usually with a high rate of success.
Congenital hemolytic jaundice
Known also as hereditary spherocytosis (HS), this is a genetic disorder of the red blood cell membrane clinically characterized by anemia, jaundice (yellowing) and splenomegaly (enlargement of the spleen).
Congenital hip dislocation
The abnormal formation of the hip joint in which the ball at the top of the thighbone (the femoral head) is not stable within the socket (the acetabulum). The ligaments of the hip joint may also be loose and stretched.
Congenital lymphedema
A condition present at birth in which excess fluid called lymph collects in tissues and causes swelling (edema) in them. Congenital lymphedema is due to a congenital malformation (that is, a birth defect) of the lymphatic system.
Congenital malformation
A physical defect present in a baby at birth, irrespective of whether the defect is caused by a genetic factor or by prenatal events that are not genetic. In a malformation, the development of a structure is arrested, delayed, or misdirected early in embryonic life and the effect is permanent.
Congenital neutropenia, severe (SCN)
Children born with this condition lack neutrophils (a type of white blood cell that is important in fighting infection). These children suffer frequent infections from bacteria which in the past led to death in three-quarters of cases before 3 years of age. This disease is also known as severe congenital neutropenia (SCN).
Congenital ptosis of the eyelids
"Drooping of the upper eyelids at birth. The lids may droop only slightly or they may cover the pupils and restrict or even block vision. Moderate or severe ptosis calls for treatment to permit normal vision development. If not corrected, amblyopia (""lazy eye"") may develop which can lead to permanently poor vision. Ptosis at birth is often caused by poor development of the levator muscle which lifts the eyelid. Children with ptosis may tip their heads back into a chin-up position to see underneath the eyelids or raise their eyebrows in an attempt to lift up the lids. Congenital ptosis rarely improves with time. Mild or moderate ptosis usually does not require surgery early in life. Treatment is usually surgery to tighten the eyelid-lifting muscles, the levators. If the levator is very weak, the lid can be attached or suspended from under the eyebrow so that the forehead muscles can do the lifting. Even after surgery, focusing problems can develop as the eyes grow and change shape. All children with ptosis, whether they have had surgery or not, should therefore be followed by an ophthalmologist."
Congenital rubella syndrome
The constellation of abnormalities caused by infection with the rubella (German measles) virus before birth. The syndrome is characterized by multiple congenital malformations (birth defects) and mental retardation.
Congenital stationary night blindness
"An inherited eye disorder that is not progressive (""stationary"") and principally affects the rod photoreceptors in the retina, impairing night vision. There may also be moderate to high myopia (short sightedness). Under good lighting conditions, there is usually no visual deficit. The disorder is diagnosed by electroretinography. There are several different types of the disorder which are inherited in an autosomal dominant, autosomal recessive, or X-linked recessive manner. The X-linked type affects almost exclusively males and accounts for the predominance of males with congenital stationary night blindness. Children with the disorder may have a fear of the dark."
Congenital torticollis
A deformity of the neck that is evident at birth. It is due to shortening of the neck muscles. Congenital torticollis tilts the head to the side on which the neck muscles are shortened so that the chin points to the other side.
Congenital vaccinia
Infection of the fetus in the last trimester of pregnancy due to bloodborne dissemination of the vaccinia virus in the pregnant woman after she has received a smallpox vaccination. The affected infant is often premature. The skin lesions in the newborn infant are like a fresh vaccination but often confluent and extensive. Death almost always occurs before birth or shortly thereafter. To prevent this dire disorder, it is recommended that pregnant women not be vaccinated unless special circumstances may call for it (e.g., they have been exposed to a smallpox patient or are a household member of a smallpox case).
Congestive heart failure
A condition in which the heart cannot pump out all of the blood that enters it, which leads to an accumulation of blood in the vessels and fluid in the body tissues.
Congestive Heart Failure
Heart failure caused by loss of pumping power by the heart, resulting in fluids collecting in the body. Congestive heart failure often develops gradually over several years, although it also can happen suddenly. It can be treated by drugs and in some cases, by surgery.
Congestive Heart Failure (CHF or heart failure)
A condition where the heart muscle weakens and can not pump blood efficiently throughout the body.
PREVIOUS AND NEXT TERMS--------------------------------------
Condyloma subcutaneum
Molluscum contagiosum. Wartlike growths around the anus and genitals caused by a virus. Molluscum contagiosum is a contagious disease of the skin marked by the occurrence of soft rounded tumors of the skin caused by the growth of a virus belonging to the family Poxviridae. The disease is characterized by the appearance of few to numerous small, pearly, umbilicated downgrowths (the condyloma subcutaneum).
Cone dystrophy
A disease of the cones, the specialized light-sensitive cells that act as photoreceptors in the retina of the eye, providing sharp central vision and color vision. The cone dystrophies are a form of genetic macular degeneration characterized by progressive deterioration of the cones that leads to the distinctive triad of loss of color vision, photophobia, and reduced central vision. Cone dystrophy genes have been mapped to chromosome regions 6p21.1, 6q25-q26, 17p12-13, and Xp21.1-p11.3. In region 6p21.1, mutations have been found in the gene that encodes GCAP1, a key component in the recovery of photoreceptor cells to the dark-adapted state after exposure to a light stimulus.
Cone snail
A fishing-eating snail (Conidae) that inhabits tropical coral reefs and produces toxins that immobilize their prey.
Conformal radiation therapy
A procedure that uses computers to create a 3-dimensional picture of the tumor in order to target the tumor as accurately as possible and give it the highest possible dose of radiation while sparing normal tissue as much as possible. It is also known as 3-D or conformational radiation therapy.
Conformational radiation therapy
A procedure that uses computers to create a 3-dimensional picture of the tumor in order to target the tumor as accurately as possible and give it the highest possible dose of radiation while sparing normal tissue as much as possible. It is also known as 3-D or conformal radiation therapy. Conventional radiation therapy directs x-rays not only at the tumor but also unavoidably at nearby healthy tissue. Conformational radiation is meant to deliver a higher dose of radiation to the cancer without causing so much damage to surrounding tissues.
Congenital achromatopsia,
Congenital anemia
1. Anemia at birth. 2. Synonym for Rh incompatibility.
Congenital anomaly
Something that is unusual or different at birth. A minor anomaly is defined as an unusual anatomic feature that is of no serious medical or cosmetic consequence to the patient. A minor anomaly of the feet might, for example, be curvature of the second toe so it overlaps the third toe a little.A major anomaly, by contrast, might be a cleft lip and palate, a birth defect of serious medical and cosmetic consequence to the child.
Congenital arthrogryposis
Nonprogressive congenital contractures that develop before birth and are evident at birth (congenital). The contractures are characterized by reduced mobility of many (multiple) joints. Congenital arthrogryposis is also called arthrogryposis multiplex congenita (AMC). In AMC the range of motion of the joints in the arms and legs is usually limited or fixed. Joints affected may include the shoulders, elbows, wrists and fingers and the hips, knees, ankles, and feet -- virtually any and all joints.
Congenital bilateral absence of vas deferens
A condition in males when the tubes that carry sperm from the testes (the vas deferens) fail to develop normally. The testes usually develop and function normally and the men have normal sexual performance, but sperm cannot be transported through the male reproductive system. Men with congenital bilateral absence of vas deferens are therefore infertile (unable to conceive a child). This condition is responsible for 2 to 5% of all infertility in men. Congenital bilateral absence of vas deferens is due to mutations in the CFTR gene (the cystic fibrosis transmembrane conductance regulator gene) which encodes a protein that functions as a channel across the cell membrane.
Congenital central hypoventilation syndrome
Failure from birth of central nervous system control over breathing while asleep. There are usually no breathing problems while awake. The involuntary (autonomic) control of respiration is impaired, but the voluntary control of ventilation which operates during waking hours is generally intact.
RELATED TERMS--------------------------------------
Hereditary
Transmitted from parent to offspring; derived from ancestry.
Vision
The sense of sight.
Cone
One of the two light receiving retinal cells (the other is the rod) that is responsible for daylight vision (e.g., color vision, high visual acuity, bright light vision). The area of the retina that provides central or reading vision, known as the fovea, contains only cones.
Achromatopsia
Characterized by a lack of color vision with poor visual acuity, nystagmus, and sensitivity to sunlight. No treatment is available except, for example, sunglasses for the sensitivity to light.
Acuity
The highest spatial frequency rsolvable with a grating of unity contrast (i.e. the maximum possibly contrast).
SIMILAR TERMS--------------------------------------
Congenital
Present at birth.
Congenital anemia
1. Anemia at birth. 2. Synonym for Rh incompatibility.
Congenital anomaly
Something that is unusual or different at birth. A minor anomaly is defined as an unusual anatomic feature that is of no serious medical or cosmetic consequence to the patient. A minor anomaly of the feet might, for example, be curvature of the second toe so it overlaps the third toe a little.A major anomaly, by contrast, might be a cleft lip and palate, a birth defect of serious medical and cosmetic consequence to the child.
Congenital arthrogryposis
Nonprogressive congenital contractures that develop before birth and are evident at birth (congenital). The contractures are characterized by reduced mobility of many (multiple) joints. Congenital arthrogryposis is also called arthrogryposis multiplex congenita (AMC). In AMC the range of motion of the joints in the arms and legs is usually limited or fixed. Joints affected may include the shoulders, elbows, wrists and fingers and the hips, knees, ankles, and feet -- virtually any and all joints.
Congenital bilateral absence of vas deferens
A condition in males when the tubes that carry sperm from the testes (the vas deferens) fail to develop normally. The testes usually develop and function normally and the men have normal sexual performance, but sperm cannot be transported through the male reproductive system. Men with congenital bilateral absence of vas deferens are therefore infertile (unable to conceive a child). This condition is responsible for 2 to 5% of all infertility in men. Congenital bilateral absence of vas deferens is due to mutations in the CFTR gene (the cystic fibrosis transmembrane conductance regulator gene) which encodes a protein that functions as a channel across the cell membrane.
Congenital central hypoventilation syndrome
Failure from birth of central nervous system control over breathing while asleep. There are usually no breathing problems while awake. The involuntary (autonomic) control of respiration is impaired, but the voluntary control of ventilation which operates during waking hours is generally intact.
Congenital deafness
Loss of hearing present at birth.
Congenital deafness and retinitis pigmentosa
Also called Usher syndrome.) A genetic disorder characterized by hearing impairment and an eye disorder called retinitis pigmentosa in which vision worsens over time. Some people with Usher syndrome also have balance problems.
Congenital defect
A birth defect.
Congenital Defects
Problems or conditions that are present at birth.
Congenital heart disease
"A malformation of the heart or the large blood vessels near the heart. The term ""congenital"" speaks only to time, not to causation; it means ""born with"" or ""present at birth."""
Congenital heart problems
May include ventricular septal defect (a hole in the septum) and transposition of the great vessels, where the pulmonary artery and the aorta are reversed. May be corrected with surgery soon after birth, usually with a high rate of success.
Congenital hemolytic jaundice
Known also as hereditary spherocytosis (HS), this is a genetic disorder of the red blood cell membrane clinically characterized by anemia, jaundice (yellowing) and splenomegaly (enlargement of the spleen).
Congenital hip dislocation
The abnormal formation of the hip joint in which the ball at the top of the thighbone (the femoral head) is not stable within the socket (the acetabulum). The ligaments of the hip joint may also be loose and stretched.
Congenital lymphedema
A condition present at birth in which excess fluid called lymph collects in tissues and causes swelling (edema) in them. Congenital lymphedema is due to a congenital malformation (that is, a birth defect) of the lymphatic system.
Congenital malformation
A physical defect present in a baby at birth, irrespective of whether the defect is caused by a genetic factor or by prenatal events that are not genetic. In a malformation, the development of a structure is arrested, delayed, or misdirected early in embryonic life and the effect is permanent.
Congenital neutropenia, severe (SCN)
Children born with this condition lack neutrophils (a type of white blood cell that is important in fighting infection). These children suffer frequent infections from bacteria which in the past led to death in three-quarters of cases before 3 years of age. This disease is also known as severe congenital neutropenia (SCN).
Congenital ptosis of the eyelids
"Drooping of the upper eyelids at birth. The lids may droop only slightly or they may cover the pupils and restrict or even block vision. Moderate or severe ptosis calls for treatment to permit normal vision development. If not corrected, amblyopia (""lazy eye"") may develop which can lead to permanently poor vision. Ptosis at birth is often caused by poor development of the levator muscle which lifts the eyelid. Children with ptosis may tip their heads back into a chin-up position to see underneath the eyelids or raise their eyebrows in an attempt to lift up the lids. Congenital ptosis rarely improves with time. Mild or moderate ptosis usually does not require surgery early in life. Treatment is usually surgery to tighten the eyelid-lifting muscles, the levators. If the levator is very weak, the lid can be attached or suspended from under the eyebrow so that the forehead muscles can do the lifting. Even after surgery, focusing problems can develop as the eyes grow and change shape. All children with ptosis, whether they have had surgery or not, should therefore be followed by an ophthalmologist."
Congenital rubella syndrome
The constellation of abnormalities caused by infection with the rubella (German measles) virus before birth. The syndrome is characterized by multiple congenital malformations (birth defects) and mental retardation.
Congenital stationary night blindness
"An inherited eye disorder that is not progressive (""stationary"") and principally affects the rod photoreceptors in the retina, impairing night vision. There may also be moderate to high myopia (short sightedness). Under good lighting conditions, there is usually no visual deficit. The disorder is diagnosed by electroretinography. There are several different types of the disorder which are inherited in an autosomal dominant, autosomal recessive, or X-linked recessive manner. The X-linked type affects almost exclusively males and accounts for the predominance of males with congenital stationary night blindness. Children with the disorder may have a fear of the dark."
Congenital torticollis
A deformity of the neck that is evident at birth. It is due to shortening of the neck muscles. Congenital torticollis tilts the head to the side on which the neck muscles are shortened so that the chin points to the other side.
Congenital vaccinia
Infection of the fetus in the last trimester of pregnancy due to bloodborne dissemination of the vaccinia virus in the pregnant woman after she has received a smallpox vaccination. The affected infant is often premature. The skin lesions in the newborn infant are like a fresh vaccination but often confluent and extensive. Death almost always occurs before birth or shortly thereafter. To prevent this dire disorder, it is recommended that pregnant women not be vaccinated unless special circumstances may call for it (e.g., they have been exposed to a smallpox patient or are a household member of a smallpox case).
Congestive heart failure
A condition in which the heart cannot pump out all of the blood that enters it, which leads to an accumulation of blood in the vessels and fluid in the body tissues.
Congestive Heart Failure
Heart failure caused by loss of pumping power by the heart, resulting in fluids collecting in the body. Congestive heart failure often develops gradually over several years, although it also can happen suddenly. It can be treated by drugs and in some cases, by surgery.
Congestive Heart Failure (CHF or heart failure)
A condition where the heart muscle weakens and can not pump blood efficiently throughout the body.
PREVIOUS AND NEXT TERMS--------------------------------------
Condyloma subcutaneum
Molluscum contagiosum. Wartlike growths around the anus and genitals caused by a virus. Molluscum contagiosum is a contagious disease of the skin marked by the occurrence of soft rounded tumors of the skin caused by the growth of a virus belonging to the family Poxviridae. The disease is characterized by the appearance of few to numerous small, pearly, umbilicated downgrowths (the condyloma subcutaneum).
Cone dystrophy
A disease of the cones, the specialized light-sensitive cells that act as photoreceptors in the retina of the eye, providing sharp central vision and color vision. The cone dystrophies are a form of genetic macular degeneration characterized by progressive deterioration of the cones that leads to the distinctive triad of loss of color vision, photophobia, and reduced central vision. Cone dystrophy genes have been mapped to chromosome regions 6p21.1, 6q25-q26, 17p12-13, and Xp21.1-p11.3. In region 6p21.1, mutations have been found in the gene that encodes GCAP1, a key component in the recovery of photoreceptor cells to the dark-adapted state after exposure to a light stimulus.
Cone snail
A fishing-eating snail (Conidae) that inhabits tropical coral reefs and produces toxins that immobilize their prey.
Conformal radiation therapy
A procedure that uses computers to create a 3-dimensional picture of the tumor in order to target the tumor as accurately as possible and give it the highest possible dose of radiation while sparing normal tissue as much as possible. It is also known as 3-D or conformational radiation therapy.
Conformational radiation therapy
A procedure that uses computers to create a 3-dimensional picture of the tumor in order to target the tumor as accurately as possible and give it the highest possible dose of radiation while sparing normal tissue as much as possible. It is also known as 3-D or conformal radiation therapy. Conventional radiation therapy directs x-rays not only at the tumor but also unavoidably at nearby healthy tissue. Conformational radiation is meant to deliver a higher dose of radiation to the cancer without causing so much damage to surrounding tissues.
Congenital achromatopsia,
Congenital anemia
1. Anemia at birth. 2. Synonym for Rh incompatibility.
Congenital anomaly
Something that is unusual or different at birth. A minor anomaly is defined as an unusual anatomic feature that is of no serious medical or cosmetic consequence to the patient. A minor anomaly of the feet might, for example, be curvature of the second toe so it overlaps the third toe a little.A major anomaly, by contrast, might be a cleft lip and palate, a birth defect of serious medical and cosmetic consequence to the child.
Congenital arthrogryposis
Nonprogressive congenital contractures that develop before birth and are evident at birth (congenital). The contractures are characterized by reduced mobility of many (multiple) joints. Congenital arthrogryposis is also called arthrogryposis multiplex congenita (AMC). In AMC the range of motion of the joints in the arms and legs is usually limited or fixed. Joints affected may include the shoulders, elbows, wrists and fingers and the hips, knees, ankles, and feet -- virtually any and all joints.
Congenital bilateral absence of vas deferens
A condition in males when the tubes that carry sperm from the testes (the vas deferens) fail to develop normally. The testes usually develop and function normally and the men have normal sexual performance, but sperm cannot be transported through the male reproductive system. Men with congenital bilateral absence of vas deferens are therefore infertile (unable to conceive a child). This condition is responsible for 2 to 5% of all infertility in men. Congenital bilateral absence of vas deferens is due to mutations in the CFTR gene (the cystic fibrosis transmembrane conductance regulator gene) which encodes a protein that functions as a channel across the cell membrane.
Congenital central hypoventilation syndrome
Failure from birth of central nervous system control over breathing while asleep. There are usually no breathing problems while awake. The involuntary (autonomic) control of respiration is impaired, but the voluntary control of ventilation which operates during waking hours is generally intact.
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This dictionary contains 19186 terms.
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