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Congenital adrenal hyperplasia (CAH) due to 11-beta-hydroxylase deficiency is one of a group of disorders (collectively called congenital adrenal hyperplasia) that affect the adrenal glands. In this condition, the adrenal glands produce excess androgens (male sex hormones). This condition is caused by mutations in the CYP11B1 gene and is inherited in an autosomal recessive pattern. There are two…

12q14 microdeletion syndrome is a genetic syndrome caused by a missing piece of chromosome 12. The signs and symptoms depend on the size of the missing piece and the genes involved, but generally include growth delay, short stature and feeding difficulties. When this syndrome is inherited, it is passed on in a dominant pattern. It…

15q11.2 microdeletion refers to a chromosome abnormality in which a tiny piece of genetic material on the long arm of chromosome 15 (at a location designated q11.2) is missing (deleted). The features of people with a 15q11.2 microdeletion vary widely.[1] The most common features include developmental, motor, and language delays; behavior and emotional problems; attention…

15q13.3 microdeletion syndrome is a genetic disorder caused by a deletion of several genes on chromosome 15. When a syndrome is caused by the deletion of several genes, it is also known as a microdeletion syndrome or a contiguous gene deletion syndrome. Individuals with 15q13.3 microdeletion syndrome may have very different signs and symptoms from other…

15q13.3 microduplication syndrome is a rare chromosomal disorder. Our genetic information is organized in structures called chromosomes. People with 15q13.3 microduplication syndrome have an extra piece of genetic information on the long arm (q arm) of chromosome 15. Some people with this duplication do not have any medical or behavioral problems. Other people may have developmental delay, intellectual disability,…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 94065 Definition 15q24 microdeletion syndrome is a rare chromosomal anomaly characterized cytogenetically by a 1.7-6.1 Mb deletion in chromosome 15q24 and clinically by preand post-natal growth retardation, intellectual disability, distinct facial features, and genital, skeletal,…

16p11.2 deletion syndrome is a condition caused by a missing piece (deletion) on a specific region of chromosome 16 designated as p11.2. People with 16p11.2 deletion syndrome usually have developmental delay and intellectual disability. Most also have at least some features of autism spectrum disorder. Some affected people have minor physical abnormalities; however, signs and…

16p11.2 duplication is a chromosomal change in which a small amount of genetic material within chromosome 16 is abnormally copied (duplicated). This duplication occurs in the short (p) arm of chromosome 16 at a position known as 11.2. Signs and symptoms can vary widely among affected individuals. Some individuals have no symptoms while others may…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 261243 Definition 16p13.11 microduplication syndrome is a recently described syndrome associated with variable clinical features including behavioral abnormalities, developmental delay, congenital heart defects and skeletal anomalies. Epidemiology It has been clinically and molecularly characterized in…

16q24.3 microdeletion syndrome is a chromosome abnormality that can affect many parts of the body. People with this condition are missing a small piece (deletion) of chromosome 16 at a location designated q24.3. Signs and symptoms may include developmental delay, characteristic facial features, seizures and autism spectrum disorder.[1][2][3] Chromosome testing of both parents can provide…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 90793 Definition A very rare form of congenital adrenal hyperplasia (CAH) characterized by glucocorticoid deficiency, hypergonadotrophic hypogonadism and severe hypokalemic hypertension. Epidemiology It accounts for approximately 1% of all CAH cases. The prevalence is therefore…

17-beta hydroxysteroid dehydrogenase 3 deficiencyis an inherited condition that affects male sexual development. People with this condition are genetically male and have testes, but do not produce enough testosterone. Most people with this condition are born with external genitalia that appear female. In some cases, the external genitalia are ambiguous or appear male but are…

17q12 deletion syndrome is a chromosome abnormality in which there is a small missing piece (deletion) of genetic material on the long arm (q) of chromosome 17. Signs and symptoms can vary widely among people with this syndrome. More common signs and symptoms include abnormalities of the kidneys or urinary tract, a form of diabetes…

17q12 duplication occurs when a person has an extra copy of a portion of chromosome 17. Our genetic information is organized in structures called chromosomes. People with 17q12 duplication have an extra piece of genetic information from chromosome 17. Some people with this duplication do not have any signs or symptoms. Other people may have…

17q23.1q23.2 microdeletion syndrome is a condition caused by a small deletion of genetic material from chromosome 17. The deletion occurs at a location encompassing bands 23.1 to 23.2 on the long (q) arm of the chromosome. People with 17q23.1q23.2 microdeletion syndrome may have developmental delay, microcephaly, short stature, heart defects and limb abnormalities. Most cases are approximately 2.2 Mb…

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The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 254346 Definition 19p13.12 microdeletion syndrome is a newly described syndrome characterized by moderate to severe developmental delay, language delay, bilateral sensorineural and/or conductive hearing loss and facial dysmorphism. Epidemiology It has been reported in 6…

Chromosome 1q duplications are chromosome abnormalies that occurs when there is an extra copy of genetic material on the long arm (q) of chromosome 1. The severity of the condition and the signs and symptoms depend on the size and location of the duplication and which genes are involved. Features that may occur in people with chromosome…

1q21.1 microdeletion syndrome is a chromosome abnormality where a segment of genetic material on the long arm (or q arm) of chromosome 1 at position 21.1 is missing (or deleted). Some people with this deletion have no observable features while others have variable findings that can include a small head (microcephaly), developmental delay (speech and motor delays), mild intellectual disability, distinctive…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 238769 Definition 1q44 microdeletion syndrome is a newly described syndrome associated with facial dysmorphism, developmental delay, in particular of expressive speech, seizures and hypotonia. Epidemiology It has been reported in four unrelated patients. Clinical description…

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2-methylbutyryl-CoA dehydrogenase deficiency is an organic acid disorder in which individuals lack adequate levels of an enzyme called 2-methylbutyryl-CoA dehydrogenase. This enzyme assists in the processing of a particular amino acid called isoleucine. The inability to process isoleucine correctly leads to the buildup of the amino acid in the body. The buildup can cause a variety of…

2,4-Dienoyl-CoA reductase deficiency is associated with hypotonia and respiratory acidosis in infancy. This condition may be associated with the DECR1 gene and likely has an autosomal recessive pattern of inheritance.[1]

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 261295 Definition 20p12.3 microdeletion syndrome is a recently described syndrome characterized by Wolff-Parkinson-White syndrome (see this term), variable developmental delay and facial dysmorphism. Epidemiology It has been clinically and molecularly characterized in 3 patients. Clinical…

21-hydroxylase deficiency is the most common cause of congenital adrenal hyperplasia (CAH). CAH is a group of disorders that affect how the adrenal glands work. In 21-hydroxylase deficiency, a missing enzyme leads to overproduction of specific hormones made by the adrenal glands. There are three types of 21-hydroxylase deficiency that vary by the severity of symptoms….

22q11.2 deletion syndrome is a disorder that involves many different areas of the body and can vary greatly in severity among people with the condition. Signs and symptoms may include: cleft palate, heart defects, recurrent infections, unique facial characteristics, feeding problems, kidney abnormalities, hypoparathyroidism, thrombocytopenia, scoliosis, hearing loss, developmental delay, and learning disabilities. People with this…

22q11.2 duplication syndrome is a condition caused by an extra copy of a small piece of chromosome 22 which contains about 30 to 40 genes. The features of this condition vary widely, even among members of the same family (intrafamilial variability). Affected individuals may have intellectual or learning disability, developmental delay, slow growth leading to short stature, and weak…

22q13.3 deletion syndrome, also known as Phelan-McDermid syndrome, is a chromosome disorder caused by the loss (deletion) of a small piece of chromosome 22. The deletion occurs near the end of the long arm (or q arm) of the chromosome at a location designated as q13.3. Not everyone with 22q13.3 deletion syndrome will have the same medical, developmental,…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 261349 Definition 2p15p16.1 microdeletion syndrome is a recently described syndrome characterized by developmental delay and facial dysmorphism. Epidemiology It has been clinically and molecularly characterized in 5 patients. Clinical description Dysmorphic features include receding forehead,…

2q23.1 microdeletion syndrome is a rare chromosome disorder. Symptoms may include seizures, moderate to severe learning problems, speech delays, behavior problems, trouble sleeping, and developmental delays (learn to crawl, sit or walk later than other babies). Children affected by 2q23.1 microdeletion syndrome may also have low muscle tone (hypotonia), slow weight gain, and may be…

2q37 deletion syndrome is a chromosome disease that can affect many parts of the body. About 100 cases have been reported worldwide. This condition is characterized by short stature, weak muscle tone (hypotonia) in infancy, mild to severe intellectual disability and developmental delay, autistic behavior, obesity, characteristic facial features, and other physical abnormalities, such as…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 71212 Definition Hyperinsulinism due to short chain 3 hydroxylacyl-CoA dehydrogenase (SCHAD) deficiency is a recently described mitochondrial fatty acid oxidation disorder characterized by hyperinsulinemic hypoglycemia with seizures, and in one case fulminant hepatic failure. Epidemiology…

3-beta-hydroxysteroid dehydrogenase (3BHSD) deficiency is a form of congenital adrenal hyperplasia, a group of conditions that interfere with the body’s ability to make hormones. People with this condition lack many of the hormones made in the gonads (testes or ovaries) and the adrenal glands. There are three types of 3BHSD deficiency the salt-wasting form, non-salt-wasting form,…

3-Hydroxyisobutyric aciduria is a rare metabolic condition in which the body is unable to breakdown certain amino acids (the building blocks of protein). This leads to a toxic buildup of particular acids known as organic acids in the blood (organic acidemia), tissues and urine (organic aciduria). Signs and symptoms of 3-hydroxyisobutyric aciduria include developmental delay,…

3-methylcrotonyl-CoA carboxylase deficiency (3-MCC deficiency) is an inherited condition in which the body is unable to breakdown the amino acid, leucine (a building block of protein). Some children with 3-MCC deficiency will begin developing signs and symptoms during infancy or early childhood; however, more recent studies suggest that many affected babies identified through newborn screening…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 67046 Definition 3-methylglutaconic aciduria (3-MGA) type I is an inborn error of leucine metabolism with a variable clinical phenotype ranging from mildly delayed speech to psychomotor retardation, coma, failure to thrive, metabolic acidosis and dystonia….

3M syndrome is a growth disorder that causes short stature, characteristic facial features, and skeletal abnormalities. Intelligence is normal.[1][2][3][4] The name comes from the initials of three researchers who first identified it: Miller, McKusick, and Malvaux.[4] 3M syndrome is caused by mutations in one of three genes: CUL7, OBSL1, and CCDC8.[1][2][3] It is inherited in…

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3q29 microdeletion syndrome is a rare chromosome disorder. Symptoms may include delay reaching some developmental milestones such as sitting, walking or talking, frequent ear and respiratory infections, and a small head size (microcephaly). Some babies with this condition are born with a cleft lip or cleft palate, and a few have been reported to have…

A 46, XY disorder of sex development (DSD) is a condition in which an individual with one X chromosome and one Y chromosome in each cell, the pattern normally found in males, have genitalia that is not clearly male or female. Infants with this condition tend to have penoscrotal hypospadias, abnormal development of the testes, and…

46,XX testicular disorder of sex development is a condition in which a person with two X chromosomes (which is normally found in females) has a male appearance. More specifically, people with this condition have male external genitalia, ranging from normal to ambiguous. Other common signs and symptoms include small testes, gynecomastia, infertility due to azoospermia…

47 XXX syndrome, also called trisomy X or triple X syndrome, is characterized by the presence of an additional (third) X chromosome in each of a female’s cells (which normally have two X chromosomes). An extra copy of the X chromosome is associated with tall stature, learning problems, and other features in some girls and women. Seizures or…

47, XYY syndrome is a syndrome (group of signs and symptoms) that affects males. For some males with this syndrome, signs and symptoms are barely noticeable. For others, signs and symptoms may include learning disabilities, speech delay, low muscle tone (hypotonia), and being taller than expected.[1][2] 47, XYY syndrome is caused by having an extra…

48,XXXY syndrome is a type of chromosome abnormality characterized by the presence of 2 extra X chromosomes in males. It is sometimes referred to as a variant of Klinefelter syndrome, but differs from Klinefelter syndrome in many ways and is more severe.[1] Signs and symptoms of 48,XXXY syndrome can vary but may include learning difficulties; intellectual…

48,XXYY syndrome is a chromosomal condition, characterized by the presence of an extra X and Y chromosome in males, that causes medical and behavioral problems. 48,XXYY can be considered a variant of Klinefelter syndrome. Individuals with 48,XXYY are usually considerably tall with small testes that do not function normally leading to infertility. In addition, affected individuals have behavioral problems such as…

49,XXXXY syndrome is a type of chromosome abnormality characterized by the presence of 3 extra X chromosomes in males. It is sometimes referred to as a variant of Klinefelter syndrome, but differs from Klinefelter syndrome in many ways and is more severe.[1] Signs and symptoms of 49,XXXXY syndrome can vary but may include learning difficulties or intellectual…

49, XXXYY syndrome is a chromosome abnormality that occurs when a male inherits two extra copies of the X chromosome and one extra copy of the Y chromosome. The condition is extremely rare with only a handful of cases reported in the medical literature. Signs and symptoms associated with these cases include severe intellectual disability,…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 11 Definition Pentasomy X is a sex chromosome anomaly caused by the presence of three extra X chromosomes in females (49,XXXXX instead of 46,XX). Epidemiology The prevalence is unknown but less than 40 cases have…

5-alpha reductase deficiency is an inherited condition that primarily affects male sexual development before birth and during puberty. People with this condition are genetically male, with one X and one Y chromosome in each cell, and they have male gonads (testes). Their bodies, however, do not produce enough of a hormone called dihydrotestosterone (DHT), which is…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 33572 Definition A very heterogeneous condition characterized by 5-oxoprolinuria. Epidemiology It has been detected in eight patients worldwide. All affected patients have been identified because of 5-oxoprolinuria. Clinical description Symptoms reported in individual patients include…

5q14.3 microdeletion syndrome is characterized by severe intellectual disability, absent speech, stereotypic movements and epilepsy. Unusual facial features include high broad forehead with variable small chin, short nose with anteverted nares (nostrils that open to the front rather than downward), large open mouth, upslanted palpebral fissures (outside corners of the eyes that point downward), and prominent eyebrows. The…

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The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 13 Definition 6-pyruvoyl-tetrahydropterin synthase (PTPS) deficiency is one of the causes of malignant hyperphenylalaninemia due to tetrahydrobiopterin deficiency. Not only does tetrahydrobiopterin deficiency cause hyperphenylalaninemia, it is also responsible for defective neurotransmission of monoamines because…

7q11.23 duplication syndrome is a chromosome abnormality characterized by a variety of neurological and behavioral differences.[1] It is caused by a small amount of additional (duplicated) genetic material from chromosome 7. Symptoms may include: motor, speech and language delay, behavior problems, intellectual disability, low muscle tone (hypotonia), an increased head circumference (macrocephaly), facial dysmorphism, seizures,…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 96092 Definition 8p inverted duplication/deletion [invdupdel(8p)] syndrome is a rare chromosomal anomaly characterized clinically by mild to severe intellectual deficit, severe developmental delay (psychomotor and speech development), hypotonia with tendency to develop progressive hypertonia and…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 228399 Definition The newly described 8q12 microduplication syndrome is associated with unusual and characteristic multiorgan clinical features, which include hearing loss, congenital heart defects, intellectual disability, hypotonia in infancy, and Duane anomaly (see this term)….

Aagenaes syndrome, or lymphedema cholestasis syndrome (LSC1), is a form of idiopathic familial intrahepatic cholestasis associated with lymphedema of the lower extremities.[1][2] At least some cases of Aagenaes syndrome have been attributed to mutations in the LSC1 gene on chromosome 15q.[3] This condition is inherited in an autosomal recessive manner and is found mainly in individuals of Norwegian descent.[2]

Aarskog syndrome is an inherited disease that affects a person’s height, muscles, skeleton, genitals, and appearance of the face.[1] Intellectual development may also be affected. About 20 percent of people with Aarskog-Scott syndrome have mutations in the FGD1 gene. The cause in other affected individuals is unknown. The condition is inherited in an X-linked recessive pattern.[1][2]

Abdominal aortic aneurysms (AAAs) are aneurysms that occur in the part of the aorta that passes through the abdomen. They may occur at any age, but are most common in men between 50 and 80 years of age. Many people with an AAA have no symptoms, but some people have a pulsing sensation in the…

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Abdominal cystic lymphangioma is a benign (noncancerous) malformation of the lymphatic vessels in the abdomen. These vessels carry lymph, a fluid that contains white blood cells that fight infection, throughout the body. The severity of the condition and the associated features vary from person to person. When present, signs and symptoms may include abdominal pain, an…

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Aberrant subclavian artery is a rare vascular anomaly that is present from birth. It usually causes no symptoms and is often discovered as an incidental finding (such as through a barium swallow or echocardiogram). Occasionally the anomaly causes swallowing difficulty (dysphagia lusoria).[1][2] Swallowing symptoms in children may present as feeding difficulty and/or recurrent respiratory tract infection.[2] When aberrant subclavian…

Abetalipoproteinemia is a very rare condition that affects fat and vitamin absorption by the intestines and liver, leading to very low LDL-cholesterol and malnutrition. Early symptoms of this condition include diarrhea, vomiting, and poor growth. Without treatment, later complications may include muscle weakness, poor night and color vision, tremors, and speech difficulties.[1][2] The long-term outcome can…

Ablepharon macrostomia syndrome is genetic disorder characterized by absent eyelids (ablepharon) and very large mouth (macrostomia). Other common signs and symptoms include abnormal external ears, fusion (syndactyly) of the hands and feet, skin findings (such as dry and coarse skin or redundant folds of skin), absent or sparse hair, genital malformations, and developmental delay. Other…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 97345 Definition A rare, neurodegenerative disease characterized by progressive cognitive impairment, spastic tetraparesis, and cerebellar ataxia resulting from amyloid deposits in the brain. Spasticity with increased deep tendon reflexes and tone are early symptoms, muscular…

Abruzzo-Erickson syndrome is an extremely rare condition characterized by cleft palate, coloboma, hypospadius, deafness, short stature, and radioulnar synostosis.[1] Although the underlying cause of the condition is still being studied, it appears to result, at least in part, from mutations in the TBX22 gene.[1][2][3] The condition is inherited in an X-linked recessive manner.[1][2] Treatment is generally aimed at…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 1658 Definition A rare syndrome syndrome characterized by neonatal blisters and milia (small white papules, especially on the face) and congenital absence of dermatoglyphics on the hands and feet. It has been reported in two…

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The absence of the septum pellucidum is a rare condition that affects the structure of the brain. Specifically, a thin membrane called the septum pellucidum is missing from its normal position in the middle of the brain.[1] When it is missing, symptoms may include learning difficulties, behavioral changes, seizures, and changes in vision. Absence of…

Absence of tibia is a rare birth defect that is characterized by deficiency of the tibia (the shinbone) with other bones of the lower leg relatively intact. The condition may affect one or both legs. Some cases are isolated birth defects, while others are associated with a variety of skeletal and other malformations.[1][2] It can…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 988 Definition Tibial hemimelia-polysyndactyly-triphalangeal thumb syndrome is a rare, genetic dysostosis syndrome, with marked interand intrafamilial variation, typically characterized by triphalangeal thumbs, hand and/or foot polysyndactyly and/or absent/hypoplastic tibiae (associated with duplication of fibulae in…

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The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 86789 Definition Isolated patella aplasia-hypoplasia is an extremely rare genetic condition characterized by congenital absence or marked reduction of the patellar bone described in only a few families to date. Visit the Orphanet disease page…

Primary acalvaria is an extremely rare malformation characterized by the absence of the flat skull bones of the brain, dura mater, and scalp muscles. The skull base and facial features are fully formed and usually appear normal.[1][2][3] The cause of acalvaria is still unknown.[1] Acalvaria can be distinguished from anencephaly, the most common differential diagnosis, by the presence of a layer of…

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An acanthoma is a small, reddish bump that usually develops on the skin of an older adult. There are several types of acanthoma, including “acantholytic”, “epidermolytic”, “clear cell“, and “melanoacanthoma”.[1] Though most individuals have only one acanthoma, there have been rare reports of individuals who have developed many. The exact cause of acanthoma is not known; it…

Acanthosis nigricans (AN) is a skin disorder in which there is darker, thick, velvety skin in body folds and creases. This condition usually appears slowly and doesn’t cause any symptoms other than skin changes. Eventually, dark, velvety skin with very visible markings and creases appears in the armpits, groin and neck folds, and over the…

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The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 926 Definition A rare congenital disorder resulting from a deficiency in erythrocyte catalase, an enzyme responsible for the breakdown of hydrogen peroxide. Epidemiology The disorder is very rare in the general population with an estimated…

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An accessory navicular bone is an extra bone or piece of cartilage located in the middle of the foot near the navicular bone, the bone that goes across the foot near the instep. It is present from birth (congenital) and is a common trait.[1][2] The reported incidence differs among populations and ethnic groups, and they…

The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 674 Definition A rare asymptomatic embryopathy characterized by the presence of pancreatic tissue in other sites of the body such as the splenic pedicle, gonadic pedicles, intestinal mesentery, duodenum wall, upper jejunum, or, more rarely,…

Arterial calcification due to deficiency of CD73, or ACDC, is a rare, adult-onset vascular disorder. People with ACDC have calcium build-up in the large vessels (mainly below the waist) and in the joints of the hands and feet. Signs and symptoms may include progressive pain and cramping in the calves, thighs, buttocks, feet, and/or hands.[1][2]…

Aceruloplasminemia causes a build-up of iron in the brain and the organs of the body. Signs and symptoms begin in adulthood. People with aceruloplasminemia develop anemia, diabetes, and eye problems. Over time, difficulty controlling movements may occur. These include tremors, chorea, ataxia, eyelid twitching, and grimacing. Some experience psychiatric problems and dementia in their 40’s and 50’s….

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The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs. Orpha Number: 929 Definition An extremely rare genetic syndrome characterized by the association of microcephaly, intellectual deficit and achalasia (with symptoms of coughing, dysphagia, vomiting, failure to thrive and aspiration appearing in infancy/early-childhood). Antenatal exposure to Mefloquine…

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Acheiropody is a very rare condition characterized by bilateral, congenital amputations of the hands and feet. Individuals with this condition are born with complete amputation of the distal humeral epiphysis (end of the upper arm bone) and tibial diaphysis (mid-section of the shin bone), and aplasia (lack of development) of the radius, ulna, fibula, and of all the…

Achondrogenesis is a group of severe disorders that are present from birth and affect the development of cartilage and bone. Infants with achondrogenesis usually have a small body, extremely short arms and legs, other skeletal abnormalities, and underdeveloped lungs.[1][2] There are at least three forms of achondrogenesis, type 1A, type 1B and type 2. Achondrogenesis…

Achondroplasia is a disorder of bone growth that prevents the changing of cartilage (particularly in the long bones of the arms and legs) to bone. It is characterized by dwarfism, limited range of motion at the elbows, large head size (macrocephaly), small fingers, and normal intelligence. Achondroplasia can cause health complications such as interruption of…

Achromatopsia 2 is a condition that affects the color vision. Most people have complete achromatopsia which is characterized by a total absence of color vision (only able to see black, white and shades of gray). Rarely, affected people may have incomplete achromatopsia which is associated with some color discrimination. Other common signs and symptoms include…