Diseases

NADH cytochrome B5 reductase deficiency

Methemoglobinemia due to NADH-cytochrome b5 reductase deficiency (recessive congenital methemoglobinemia, RCM) is an autosomal recessive disorder characterized clinically by decreased oxygen carrying capacity of the blood, with resultant cyanosis and hypoxia.

There are 2 types of RCM. In type I, the defect affects the soluble form of the enzyme, is restricted to red blood cells, and causes well-tolerated methemoglobinemia. In type II, the defect affects both the soluble and microsomal forms of the enzyme and is thus generalized, affecting red cells, leukocytes, and all body tissues. Type II methemoglobinemia is associated with mental deficiency and other neurologic symptoms. The neurologic symptoms may be related to the major role played by the cytochrome b5 system in the desaturation of fatty acids. 

Naegeli syndrome

Naegeli syndrome is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Naegeli syndrome, or a subtype of Naegeli syndrome, affects less than 200,000 people in the US population.

Naguib-Richieri-Costa syndrome

Naguib-Richieri-Costa syndrome (NRCS) is a very rare syndrome associating an acro-fronto-facio-nasal dysostosis with genitourinary anomalies. It has been described in three consanguineous families, with parents being first cousins.

The suggested inheritance pattern is autosomal recessive, with an incidence of less than 1 per million. 

Nail Patella syndrome

Nail-patella syndrome is an autosomal dominant condition characterized by the classical clinical tetrad of nail dysplasia, patellar aplasia-hypoplasia, elbow arthrodysplasia, and iliac horns. The nails may be absent, hypoplastic, or dystrophic with ridges, pits, and/or triangular lunulae.

Nail-patella syndrome has been recognized for more than 100 years. It has an estimated prevalence of 1 per 50,000 live births (US). Males and females are equally affected.

Nakajo syndrome

Nakajo-Nishimura syndrome (NNS) is an inherited condition that affects many parts of the body and has been described only in the Japanese population. Beginning in infancy or early childhood, affected individuals develop red, swollen lumps (nodular erythema) on the skin that occur most often in cold weather; recurrent fevers; and elongated fingers and toes with widened and rounded tips (clubbing).

 Later in childhood, affected individuals develop joint pain and joint deformities called contractures that limit movement, particularly in the hands, wrists, and elbows. They also experience weakness and wasting of muscles, along with a loss of fatty tissue (lipodystrophy), mainly in the upper body. The combination of muscle and fat loss worsens over time, leading to an extremely thin (emaciated) appearance in the face, chest, and arms.

 Other signs and symptoms of Nakajo-Nishimura syndrome can include an enlarged liver and spleen (hepatosplenomegaly), a shortage of red blood cells (anemia), a reduced amount of blood clotting cells called platelets (thrombocytopenia), and abnormal deposits of calcium (calcification) in an area of the brain called the basal ganglia. Intellectual disability has been reported in some affected individuals.

Nakajo-Nishimura syndrome appears to be rare and has been described only in the Japanese population. About 30 cases have been reported in the medical literature. Consanguinity or familial history is observed in about seventy percent of the affected families.

Nakamura Osame syndrome

Hereditary spastic paraplegia (SPG or HSP) is characterized by progressive weakness and spasticity of the lower limbs due to degeneration of corticospinal axons. SPG11 is a form of complicated SPG, in that it has neurologic features in addition to spasticity.

The estimated prevalence for HSP of all types ranges from 1:100,000 to 10:100,000 depending on the country.

Nance-Horan syndrome

Nance-Horan syndrome is a rare genetic disorder that may be evident at birth (congenital). It is primarily characterized by abnormalities of the teeth and clouding of the lens of the eyes (congenital cataracts), resulting in poor vision. Additional eye (ocular) abnormalities are also often present, such as unusual smallness of the front, clear portion of the eye through which light passes (microcornea) and involuntary, rapid, rhythmic eye movements (nystagmus). In some cases, the disorder may also be associated with additional physical abnormalities and/or intellectual impairment. The range and severity of symptoms may vary greatly from one person to another, including among affected members of the same family.

Nance-Horan syndrome is inherited as an X-linked trait that it is usually fully expressed in males only. However, females who carry a single copy of the disease gene (heterozygotes) may manifest some of the symptoms and findings associated with the disorder. These may include microcornea and/or clouding of the lens of the eyes (posterior sutural cataract). Symptoms are less severe than those of affected males, potentially causing only slightly decreased clearness or clarity of vision (visual acuity). In some cases, abnormalities of the teeth may also be present. Intellectual impairment rarely occurs in females.

The disorder is present at birth (congenital). Fewer than 50 families (kindreds) have been described in the medical literature. The exact incidence of the disorder is unknown. 

Narcolepsy

Narcolepsy is a chronic brain disorder that involves poor control of sleep-wake cycles. People with narcolepsy have episodes of extreme daytime sleepiness and sudden, irresistible bouts of sleep (called "sleep attacks") that can occur at any time, and may last from seconds or minutes. Other signs and symptoms may include cataplexy (a sudden loss of muscle tone that makes a person go limp or unable to move); vivid dream-like images or hallucinations; and/or total paralysis just before falling asleep or after waking-up. Narcolepsy may have several causes, the most common being low levels of the neurotransmitter hypocretin (for various possible reasons). The disorder is usually sporadic but some cases are familial. There is no cure, but some symptoms can be managed with medicines and lifestyle changes.

NARP Syndrome

Neuropathy, ataxia, and retinitis pigmentosa (NARP) is a clinically heterogeneous progressive condition characterized by a combination of proximal neurogenic muscle weakness, sensory-motor neuropathy, ataxia, and pigmentary retinopathy.

The prevalence of NARP is unknown. This disorder is probably less common than a similar but more severe condition, Leigh syndrome, which affects about 1 in 40,000 people.

Nasal polyposis, familial

Nasal polyposis, familial ( also known as nose polyposis, familial) is a familial condition characterized by the development of nasal polyps.

Nasodigitoacoustic syndrome

Nasodigitoacoustic syndrome is a rare congenital syndrome first described by J.A. Keipert and colleagues in 1973. The syndrome is characterized by a misshaped nose, broad thumbs and halluces (the big toes), brachydactyly, sensorineural hearing loss, facial features such as hypertelorism (unusually wide-set eyes), and developmental delay.

The incidence of the syndrome has not been determined, but it is considered to affect less than 200,000 people in the United States, and no greater than 1 per 2,000 in Europe.

Nasopharyngeal carcinoma

Nasopharyngeal carcinoma is the most common cancer originating in the nasopharynx, the uppermost region of the pharynx ("throat"), behind the nose where the nasal passages and auditory tubes join the remainder of the upper respiratory tract. NPC occurs in children and adults. NPC differs significantly from other cancers of the head and neck in its occurrence, causes, clinical behavior, and treatment. It is vastly more common in certain regions of East Asia and Africa than elsewhere, with viral, dietary and genetic factors implicated in its causation. It is most common in males. It is a squamous cell carcinoma or an undifferentiated type. Squamous epithelial cells are a flat type of cell found in the skin and the membranes that line some body cavities. Differentiation means how different the cancer cells are from normal cells. Undifferentiated is a word used to describe cells that do not have their mature features or functions.

Nathalie syndrome

A very rare syndrome characterized mainly by deafness, cataracts and skeletal abnormalities

Native American myopathy

A rare genetic disorder characterized by muscle disease from birth, cleft palate and malignant hyperthermia.

Navajo neurohepatopathy

A rare genetic disease found in Navajo populations. It involves peripheral nerve degeneration, liver disease and corneal ulcers. The genetic disease is believed to be caused by maternal exposure to uranium from waters contaminated by old mines

Navajo poikiloderma

A rare genetic blood disorder found in Navajo populations and characterized by a progressive skin disorder and neutropenia (lack of neutrophils which are needed to fight bacterial infections). Navajo poikiloderma is listed as a ""rare disease"" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Navajo poikiloderma, or a subtype of Navajo poikiloderma, affects less than 200,000 people in the US population. "

Naxos disease

Since 1995, according to the World Health Organisation’s classification of cardiomyopathies, Naxos disease has been considered as the recessive form of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C).1 It is a stereotype association of ARVD/C with a cutaneous phenotype, characterised by woolly hair and palmoplantar keratoderma.

Necrotizing enterocolitis

Necrotizing enterocolitis (NEC) is the most common GI medical/surgical emergency occurring in neonates. NEC represents a significant clinical problem and affects close to 10% of infants who weigh less than 1500 g, with mortality rates of 50% or more depending on severity. Although it is more common in premature infants, it can also be observed in term and near-term babies. Despite intensive study over the past 30 years, its etiology remains elusive

Necrotizing fasciitis

For more than a century, many authors have described soft tissue infections. Their occurrence has been on the rise because of an increase in immunocompromised patients with diabetes mellitus, cancer, alcoholism, vascular insufficiencies, organ transplants, HIV, or neutropenia. Necrotizing fasciitis can occur after trauma or around foreign bodies in surgical wounds, or it can be idiopathic, as in scrotal or penile necrotizing fasciitis. Necrotizing fasciitis has also been referred to as hemolytic streptococcal gangrene, Meleney ulcer, acute dermal gangrene, hospital gangrene, suppurative fascitis, and synergistic necrotizing cellulitis. Fournier gangrene is a form of necrotizing fasciitis that is localized to the scrotum and perineal area. Necrotizing fasciitis is a progressive, rapidly spreading, inflammatory infection located in the deep fascia, with secondary necrosis of the subcutaneous tissues. Because of the presence of gas-forming organisms, subcutaneous air is classically described in necrotizing fasciitis. This may be seen only on radiographs or not at all. The speed of spread is directly proportional to the thickness of the subcutaneous layer. Necrotizing fasciitis moves along the deep fascial plane. These infections can be difficult to recognize in their early stages, but they rapidly progress. They require aggressive treatment to combat the associated high morbidity and mortality. The causative bacteria may be aerobic, anaerobic, or mixed flora, and the expected clinical course varies from patient to patient.

NEDAMSS

Mutations like Elly’s in the IRF2BPL (Interferon regulatory factor 2 binding protein-like) gene are known to cause a neurodegenerative disease called Neurodevelopmental Disorder with Regression, Abnormal Movements, Loss of Speech, and Seizures (NEDAMSS). The mutation affects the central nervous system and is a regressive disorder. It can impact motor skills, speech, eating, and eyesight, among other functions.

While symptoms can appear in the first months of life, most individuals show their first symptoms in early childhood after meeting normal developmental milestones. Initial symptoms may include seizures, uncontrollable movements, abnormal eye movements, and developmental delays. There is no known cure or treatment for the disease

Negative rheumatoid factor polyarthritis

A form of rheumatoid arthritis which doesn't involves the presence of rheumatoid factor in the blood. Negative rheumatoid factor polyarthritis is listed as a "rare disease" by the Office of Rare Diseases (ORD) of the National Institutes of Health (NIH). This means that Negative rheumatoid factor polyarthritis, or a subtype of Negative rheumatoid factor polyarthritis, affects less than 200,000 people in the US population

Neisseria meningitidis

, also simply known as meningococcus, is a heterotrophic gram-negative diplococcal bacterium best known for its role in meningitis[1] and other forms of meningococcal disease such as meningococcemia. N. meningitidis is a major cause of morbidity and mortality in childhood in industrialized countries and is responsible for epidemics in Africa and in Asia. Anton Weichselbaum in 1887 was first reported the disease from patients infected with meningococci [2]. It is known that meningococci only infects human and never been reported from animals because the bacterium cannot get iron other than human source (transferrin and lactoferrin)[3] and it exists as normal flora in the nasopharynx of up to 40% of adults. It causes the only form of bacterial meningitis known to cause epidemics. Meningococcus is spread through the exchange of saliva and other respiratory secretions during activities like coughing, kissing, and chewing on toys. Though it initially produces with general symptoms like fatigue, it can rapidly progress from fever, headache and neck stiffness to coma and death. Death occurs in approximately 10% of cases.[4] Those with impaired immunity may be at particular risk of meningococcus (e.g. those with nephrotic syndrome or splenectomy; vaccines are given in cases of removed or non-functioning spleens). Suspicion of meningitis is a medical emergency and immediate medical assessment is recommended. Current guidance in the United Kingdom is that any doctor who suspects a case of meningococcal meningitis or septicaemia (infection of the blood) should give intravenous antibiotics (benzylpenicillin or Cefotaxime) and admit the ill person to the hospital.[5] This means that laboratory tests may be less likely to confirm the presence of Neisseria meningitidis as the antibiotics will dramatically lower the number of bacteria in the body. The UK guidance is based on the idea that the reduced ability to identify the bacteria is outweighed by reduced chance of death.

Nelson syndrome

Nelson syndrome refers to a spectrum of symptoms and signs arising from an adrenocorticotropin (ACTH)–secreting pituitary macroadenoma after a therapeutic bilateral adrenalectomy. The spectrum of clinical features observed relates to the local effects of the tumor on surrounding structures, the secondary loss of other pituitary hormones, and the effects of the high alpha-melanocyte–stimulating hormone (a-MSH), another derivative of proopiomelanocortin (POMC, the precursor peptide from which ACTH is derived) on the skin. The first case was reported by Nelson et al in 1958.

Nemaline myopathy 1

A very rare inherited muscle disorder and is characterized by muscle weakness caused by the presence of nemaline rods in the muscle tissue which affects its function. There are at least 7 different subtypes of nemaline myopathy, each with a different genetic defect. The severity of the symptoms may vary greatly even among patients within a particular subtype of the disorder. Type 1 is caused by a defect on the tropomyosin 3 gene on chromosome 1q22.

Nemaline Myopathy 2

Nemaline myopathy 2: A very rare inherited muscle disorder and is characterized by muscle weakness caused by the presence of nemaline rods in the muscle tissue which affects its function. There are at least 7 different subtypes of nemaline myopathy, each with a different genetic defect. The severity of the symptoms may vary greatly even among patients within a particular subtype of the disorder. Type 2 is caused by a defect on the nebulin gene on chromosome 2q22.

Nemaline myopathy 3

Nemaline myopathy 3: A very rare inherited muscle disorder and is characterized by muscle weakness caused by the presence of nemaline rods in the muscle tissue which affects its function. There are at least 7 different subtypes of nemaline myopathy, each with a different genetic defect. The severity of the symptoms may vary greatly even among patients within a particular subtype of the disorder. Type 3 is caused by a defect on the alpha-actin gene.

Nemaline myopathy 4

Nemaline myopathy 4: A very rare inherited muscle disorder and is characterized by muscle weakness caused by the presence of nemaline rods in the muscle tissue which affects its function. There are at least 7 different subtypes of nemaline myopathy, each with a different genetic defect. The severity of the symptoms may vary greatly even among patients within a particular subtype of the disorder. Type 4 is caused by a defect on the tropomyosin 2 gene on chromosome 9p13

Nemaline myopathy 5

Nemaline myopathy 5: A very rare inherited muscle disorder and is characterized by muscle weakness caused by the presence of nemaline rods in the muscle tissue which affects its function. There are at least 7 different subtypes of nemaline myopathy, each with a different genetic defect. The severity of the symptoms may vary greatly even among patients within a particular subtype of the disorder. Type 5 is caused by a defect on the Troponin T1 gene on chromosome 19q13.4

Nemaline myopathy 6

Nemaline myopathy 6: A very rare inherited muscle disorder and is characterized by muscle weakness caused by the presence of nemaline rods in the muscle tissue which affects its function. There are at least 7 different subtypes of nemaline myopathy, each with a different genetic defect. The severity of the symptoms may vary greatly even among patients within a particular subtype of the disorder. Type 6 is caused by a defect on chromosome 15q. Type 4 was slowly progressive but wheelchair dependency does not eventuate.

NEMO mutation with immunodeficiency

NEMO mutation with immunodeficiency: A very rare form of immunodeficiency caused by a mutation of the NEMO (NF-kappa-B essential modulator) gene on chromosome Xq28. The immunodeficiency causes sufferers to develop pus-forming bacterial infections early in life and as they get older, they tend to become susceptible to mycobacterial infections.