LEOPARD Syndrome
Noonan Syndrome
Neurofibromatoses
Protein Tyrosine Phosphatase, Non-Receptor Type 11
Lentigo
Pulmonary Subvalvular Stenosis
Panthera
Felidae
Carnivora
Encyclopedias as Topic
Hutchinson's Melanotic Freckle
LEOPARD syndrome: a new polyaneurysm association and an update on the molecular genetics of the disease. (1/34)
LEOPARD syndrome, one of many cardiocutaneous syndromes, is an acronym for some of the obvious manifestations of the disease, such as lentigines or ocular hypertelorism. The synonymous name progressive cardiomyopathic lentiginosis better indicates the morbid cardiac features that patients with the syndrome have. A patient with LEOPARD syndrome is presented. He had recurrent upper extremity aneurysms requiring multiple operations and finally PTFE reinforced venous grafts to prevent further aneurysmal degeneration. He has multiple other peripheral aneurysms, thus far asymptomatic. His diagnosis of LEOPARD syndrome was confirmed on a genetic basis. Review of the literature reveals no previous reports of severe aneurysmal disease in these patients. (+info)A novel PTPN11 gene mutation bridges Noonan syndrome, multiple lentigines/LEOPARD syndrome and Noonan-like/multiple giant cell lesion syndrome. (2/34)
Noonan (NS) and multiple lentigines/LEOPARD syndromes (LS) have proved to be associated with distinct PTPN11 mutations. Noonan-like/multiple giant cell lesion syndrome (NLS) is a rare disease, characterised by short stature, facial dysmorphisms, congenital heart defect (CHD) and central giant cell lesions. PTPN11 gene mutations have been reported in a single NLS family and two sporadic patients. Here we report a patient with a complex phenotype progressing throughout the years from NS at birth towards LS and NLS. PTPN11 gene analysis disclosed a novel missense mutation (Ala461Thr) in exon 12, affecting the consensus sequence of the SHP2-active site. This observation joins together NS and LS to NLS into a unique genetic defect, broadening the clinical and molecular spectrum of PTPN11-related disorders. (+info)LEOPARD syndrome and hypertrophic obstructive cardiomyopathy: a case report. (3/34)
The LEOPARD syndrome is a rare, autosomal dominant multisystemic disorder characterized by lentiginosis, ocular hypertelorism, abnormal genitalia, growth retardation, sensorineural deafness, and cardiac and electrocardiographic abnormalities. Although it is not cited, hypertrophic cardiomyopathy is often associated with the disease. In this study, we present a nine-year-old boy with LEOPARD syndrome and hypertrophic obstructive cardiomyopathy. (+info)Diversity and functional consequences of germline and somatic PTPN11 mutations in human disease. (4/34)
Germline mutations in PTPN11, the gene encoding the protein tyrosine phosphatase SHP-2, cause Noonan syndrome (NS) and the clinically related LEOPARD syndrome (LS), whereas somatic mutations in the same gene contribute to leukemogenesis. On the basis of our previously gathered genetic and biochemical data, we proposed a model that splits NS- and leukemia-associated PTPN11 mutations into two major classes of activating lesions with differential perturbing effects on development and hematopoiesis. To test this model, we investigated further the diversity of germline and somatic PTPN11 mutations, delineated the association of those mutations with disease, characterized biochemically a panel of mutant SHP-2 proteins recurring in NS, LS, and leukemia, and performed molecular dynamics simulations to determine the structural effects of selected mutations. Our results document a strict correlation between the identity of the lesion and disease and demonstrate that NS-causative mutations have less potency for promoting SHP-2 gain of function than do leukemia-associated ones. Furthermore, we show that the recurrent LS-causing Y279C and T468M amino acid substitutions engender loss of SHP-2 catalytic activity, identifying a previously unrecognized behavior for this class of missense PTPN11 mutations. (+info)PTPN11 (Shp2) mutations in LEOPARD syndrome have dominant negative, not activating, effects. (5/34)
Multiple lentigines/LEOPARD syndrome (LS) is a rare, autosomal dominant disorder characterized by Lentigines, Electrocardiogram abnormalities, Ocular hypertelorism, Pulmonic valvular stenosis, Abnormalities of genitalia, Retardation of growth, and Deafness. Like the more common Noonan syndrome (NS), LS is caused by germ line missense mutations in PTPN11, encoding the protein-tyrosine phosphatase Shp2. Enzymologic, structural, cell biological, and mouse genetic studies indicate that NS is caused by gain-of-function PTPN11 mutations. Because NS and LS share several features, LS has been viewed as an NS variant. We examined a panel of LS mutants, including the two most common alleles. Surprisingly, we found that in marked contrast to NS, LS mutants are catalytically defective and act as dominant negative mutations that interfere with growth factor/Erk-mitogen-activated protein kinase-mediated signaling. Molecular modeling and biochemical studies suggest that LS mutations contort the Shp2 catalytic domain and result in open, inactive forms of Shp2. Our results establish that the pathogenesis of LS and NS is distinct and suggest that these disorders should be distinguished by mutational analysis rather than clinical presentation. (+info)Reduced phosphatase activity of SHP-2 in LEOPARD syndrome: consequences for PI3K binding on Gab1. (6/34)
LEOPARD (LS) and Noonan (NS) are overlapping syndromes associated with distinct mutations of SHP-2. Whereas NS mutations enhance SHP-2 catalytic activity, we show that the activity of three representative LS mutants is undetectable when assayed using a standard protein tyrosine phosphatase (PTP) substrate. A different assay using a specific SHP-2 substrate confirms their decreased PTP activity, but also reveals a significant activity of the T468M mutant. In transfected cells stimulated with epidermal growth factor, the least active LS mutants promote Gab1/PI3K binding, validating our in vitro data. LS mutants thus display a reduced PTP activity both in vitro and in transfected cells. (+info)Noonan syndrome and related disorders: dysregulated RAS-mitogen activated protein kinase signal transduction. (7/34)
Noonan syndrome is a relatively common, genetically heterogeneous Mendelian trait with a pleiomorphic phenotype. Prior to the period covered in this review, missense mutations in PTPN11 had been found to account for nearly 50% of Noonan syndrome cases. That gene encodes SHP-2, a protein tyrosine kinase that plays diverse roles in signal transduction including signaling via the RAS-mitogen activated protein kinase (MAPK) pathway. Noonan syndrome-associated PTPN11 mutations are gain-of-function, with most disrupting SHP-2's activation-inactivation mechanism. Here, we review recent information that has elucidated further the types and effects of PTPN11 defects in Noonan syndrome and compare them to the related, but specific, missense PTPN11 mutations causing other diseases including LEOPARD syndrome and leukemias. These new data derive from biochemical and cell biological studies as well as animal modeling with fruit flies and chick embryos. The discovery of KRAS missense mutation as a minor cause of Noonan syndrome and the pathogenetic mechanisms of those mutants is discussed. Finally, the elucidation of gene defects underlying two phenotypically related disorders, Costello and cardio-facio-cutaneous syndromes is also reviewed. As these genes also encode proteins relevant for RAS-MAPK signal transduction, all of the syndromes discussed in this article now can be understood to constitute a class of disorders caused by dysregulated RAS-MAPK signaling. (+info)Noonan syndrome and related disorders: alterations in growth and puberty. (8/34)
Noonan syndrome is a relatively common multiple malformation syndrome with characteristic facies, short stature and congenital heart disease, most commonly pulmonary stenosis (Noonan, Clin Pediatr, 33:548-555, 1994). Recently, a mutation in the PTPN11 gene (Tartaglia, Mehler, Goldberg, Zampino, Brunner, Kremer et al., Nat Genet, 29:465-468, 2001) was found to be present in about 50% of individuals with Noonan syndrome. The phenotype noted in Noonan syndrome is also found in a number of other syndromes which include LEOPARD (Gorlin, Anderson, Blaw, Am J Dis Child, 17:652-662, 1969), Cardio-facio-cutaneous syndrome (Reynolds, Neri, Hermann, Blumberg, Coldwell, Miles et al., Am J Med Genet, 28:413-427, 1986) and Costello syndrome (Hennekam, Am J Med Genet, 117C(1):42-48, 2003). All three of these syndromes share similar cardiac defects and all have postnatal short stature. Very recently, HRAS mutations (Aoki, Niihori, Kawame, Kurosawa, Ohashi, Tanaka et al., Nat Genet, 37:1038-1040, 2005) have been found in the Costello syndrome and germline mutations in KRAS and BRAF genes (Rodriguez-Viciana, Tetsu, Tidyman, Estep, Conger, Santa Cruz et al., Nat Genet, 2006; Niihori, Aoki, Narumi, Neri, Cave, Verloes et al., Nat Genet, 38:294-296, 2006) in the Cardio-facio-cutaneous syndrome. Phenotypic overlap between these genetic disorders can now be explained since each is caused by germline mutations that are major components of the RAS-MAPK pathway. This pathway plays an important role in growth factor and cytokine signaling as well as cancer pathogenesis. (+info)LEOPARD syndrome is a rare genetic disorder that is characterized by multiple lentigines (freckle-like spots), electrocardiographic abnormalities, ocular hypertelorism (wide-set eyes), pulmonic stenosis (narrowing of the pulmonary valve opening), abnormal genitalia, retardation of growth, and deafness. It is caused by mutations in the PTPN11 gene, which provides instructions for making a protein called SHP-2. This protein plays important roles in signaling pathways that control various cellular functions, such as cell growth and division. The signs and symptoms of LEOPARD syndrome can vary widely among affected individuals, even among members of the same family. Treatment is typically focused on managing the specific features of the condition in each individual.
Noonan Syndrome is a genetic disorder that affects various parts of the body and is characterized by distinctive facial features, short stature, heart defects, and developmental delays. It is caused by mutations in genes responsible for regulating cell growth and division. The syndrome is often identified at birth or in early childhood due to its physical manifestations, which may include widely spaced eyes, low-set ears, a short neck, a broad or webbed neck, chest deformities, and pulmonary valve stenosis. Noonan Syndrome affects both sexes and all races equally, with an estimated prevalence of 1 in 1,000 to 1 in 2,500 live births.
Neurofibromatoses are a group of genetic disorders that primarily affect the nervous system. The term "neurofibromatosis" is often used to refer to two specific conditions: neurofibromatosis type 1 (NF1) and neurofibromatosis type 2 (NF2). These conditions are characterized by the growth of tumors on the nerves, called neurofibromas.
Neurofibromatosis type 1 (NF1): This is the most common form of neurofibromatosis, affecting about 1 in every 3,000 people worldwide. NF1 is caused by mutations in the NF1 gene and is characterized by the development of benign tumors on the nerves called neurofibromas. These tumors can develop anywhere on the body, including the skin, spinal cord, and brain. Other common features of NF1 include:
* Freckles in the underarms and groin area
* Lisch nodules (small, noncancerous growths) on the iris of the eye
* Bone abnormalities, such as scoliosis or bowing of the legs
* Learning disabilities or cognitive impairment
Neurofibromatosis type 2 (NF2): This form of neurofibromatosis is much rarer than NF1, affecting about 1 in every 30,000 people worldwide. NF2 is caused by mutations in the NF2 gene and is characterized by the development of benign tumors on the nerves that transmit sound from the inner ear to the brain (acoustic neuromas). These tumors can cause hearing loss, ringing in the ears, and balance problems. Other common features of NF2 include:
* Multiple schwannomas (tumors that develop on the protective covering of the nerves)
* Meningiomas (tumors that develop in the membranes surrounding the brain and spinal cord)
* Skin tumors called neurofibromas, although these are less common than in NF1
It is important to note that while neurofibromatoses can cause a range of symptoms and complications, most people with these conditions have a normal lifespan. With proper medical care and monitoring, it is possible to manage the symptoms and reduce the risk of complications.
Protein Tyrosine Phosphatase, Non-Receptor Type 11 (PTPN11) is a gene that encodes for the protein tyrosine phosphatase SHP-2. This enzyme regulates various cellular processes, including cell growth, differentiation, and migration, by controlling the balance of phosphorylation and dephosphorylation of proteins involved in signal transduction pathways. Mutations in PTPN11 have been associated with several human diseases, most notably Noonan syndrome and its related disorders, as well as certain types of leukemia.
A lentigo is a small, sharply defined, pigmented macule (flat spot) on the skin. It's usually tan, brown, or black and can appear on various parts of the body, particularly where the skin has been exposed to the sun. Lentigos are typically harmless and don't require treatment unless they're uncomfortable or for cosmetic reasons. However, some types of lentigines, such as lentigo maligna, can progress into melanoma, a type of skin cancer, so regular self-examinations and professional skin checks are important.
It is essential to differentiate between simple lentigos and lentigo maligna, which is a precancerous lesion. Lentigo maligna tends to occur in older individuals, often on the face, and can appear as a large, irregularly shaped, and darkly pigmented patch. A dermatologist should evaluate any suspicious or changing skin spots for proper diagnosis and treatment.
Pulmonary subvalvular stenosis is a rare cardiac condition that refers to the narrowing or obstruction of the pulmonary valve or the outflow tract below it, within the right ventricle of the heart. This results in restricted blood flow from the right ventricle to the pulmonary artery and subsequently to the lungs.
The narrowing can be caused by various factors such as a membranous shelf-like structure (dysplasia), a fibrous ring, or a tunnel-like narrowing of the outflow tract (tunneling). The severity of the stenosis may vary from mild to severe, and symptoms can range from shortness of breath, fatigue, and chest pain to more serious complications like heart failure or arrhythmias.
Diagnosis typically involves imaging tests such as echocardiography, cardiac MRI, or cardiac catheterization. Treatment options depend on the severity of the stenosis and may include monitoring, medications, or invasive procedures such as balloon dilation or surgical repair.
"Panthera" is not a medical term, but a biological genus name that includes large cats such as lions, tigers, leopards, jaguars, and snow leopards. It's a part of the taxonomic classification system used in biology to categorize and name organisms. Medical terminology typically relates to human health, disease processes, treatments, and anatomy.
Felidae is the biological family that includes all extant (living) members of the cat group, also known as felids. This family consists of big cats such as lions, tigers, and leopards, as well as small cats like domestic cats, cheetahs, and pumas. Felidae is part of the order Carnivora and is characterized by specialized adaptations for hunting and stalking prey, including retractile claws, sharp teeth, and flexible bodies. The family has a worldwide distribution, with species found in various habitats across all continents except Antarctica.
A syndrome, in medical terms, is a set of symptoms that collectively indicate or characterize a disease, disorder, or underlying pathological process. It's essentially a collection of signs and/or symptoms that frequently occur together and can suggest a particular cause or condition, even though the exact physiological mechanisms might not be fully understood.
For example, Down syndrome is characterized by specific physical features, cognitive delays, and other developmental issues resulting from an extra copy of chromosome 21. Similarly, metabolic syndromes like diabetes mellitus type 2 involve a group of risk factors such as obesity, high blood pressure, high blood sugar, and abnormal cholesterol or triglyceride levels that collectively increase the risk of heart disease, stroke, and diabetes.
It's important to note that a syndrome is not a specific diagnosis; rather, it's a pattern of symptoms that can help guide further diagnostic evaluation and management.
Carnivora is an order of mammals that consists of animals whose primary diet consists of flesh. The term "Carnivora" comes from the Latin words "caro", meaning flesh, and "vorare", meaning to devour. This order includes a wide variety of species, ranging from large predators such as lions, tigers, and bears, to smaller animals such as weasels, otters, and raccoons.
While members of the Carnivora order are often referred to as "carnivores," it is important to note that not all members exclusively eat meat. Some species, such as raccoons and bears, have an omnivorous diet that includes both plants and animals. Additionally, some species within this order have evolved specialized adaptations for their specific diets, such as the elongated canines and carnassial teeth of felids (cats) and canids (dogs), which are adapted for tearing and shearing meat.
Overall, the medical definition of Carnivora refers to an order of mammals that have a diet primarily consisting of flesh, although not all members exclusively eat meat.
An encyclopedia is a comprehensive reference work containing articles on various topics, usually arranged in alphabetical order. In the context of medicine, a medical encyclopedia is a collection of articles that provide information about a wide range of medical topics, including diseases and conditions, treatments, tests, procedures, and anatomy and physiology. Medical encyclopedias may be published in print or electronic formats and are often used as a starting point for researching medical topics. They can provide reliable and accurate information on medical subjects, making them useful resources for healthcare professionals, students, and patients alike. Some well-known examples of medical encyclopedias include the Merck Manual and the Stedman's Medical Dictionary.
Hutchinson's melanotic freckle, also known as Hutchinson's melanotic macule or naevus, is a type of pigmented lesion that can be a precursor to malignant melanoma, a serious form of skin cancer. It is typically characterized by the presence of darkly pigmented, irregularly shaped patches on the skin, often found on the face or neck.
The lesions are usually brown or black in color and may have an uneven border or surface. They can vary in size from a few millimeters to several centimeters in diameter. Hutchinson's melanotic freckles are typically larger, darker, and more irregularly shaped than common freckles.
These lesions are named after Sir Jonathan Hutchinson, an English surgeon and pathologist who first described them in the late 19th century. It is important to note that while Hutchinson's melanotic freckles can be a sign of increased risk for developing melanoma, not all such lesions will become cancerous. However, any changes in size, shape, or color of these lesions should be evaluated by a healthcare professional as soon as possible.