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Laron Syndrome
Laron syndrome (LS), also known as growth hormone insensitivity or growth hormone receptor deficiency (GHRD), is an autosomal recessive disorder characterized by a lack of insulin-like growth factor 1 (IGF-1; somatomedin) production in response to growth hormone (GH; hGH; somatotropin). It is usually caused by inherited growth hormone receptor (GHR) mutations. Affected individuals classically present with short stature between −4 to −10 standard deviations below median height, obesity, craniofacial abnormalities, micropenis, low blood sugar, and low serum IGF-1 despite elevated basal serum GH. LS is a very rare condition with a total of 250 known individuals worldwide. The genetic origins of these individuals have been traced back to Mediterranean, South Asian, and Semitic ancestors, with the latter group comprising the majority of cases. Molecular genetic testing for growth hormone receptor gene mutations confirms the diagnosis of LS, but clinical evaluation may include ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Growth Hormone
Growth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in human development. GH also stimulates production of IGF-1 and increases the concentration of glucose and free fatty acids. It is a type of mitogen which is specific only to the receptors on certain types of cells. GH is a 191-amino acid, single-chain polypeptide that is synthesized, stored and secreted by somatotropic cells within the lateral wings of the anterior pituitary gland. A recombinant form of hGH called somatropin ( INN) is used as a prescription drug to treat children's growth disorders and adult growth hormone deficiency. In the United States, it is only available legally from pharmacies by prescription from a licensed health care provider. In recent years in the United States, some health care providers are prescribin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Incidence (epidemiology)
In epidemiology, incidence is a measure of the probability of occurrence of a given medical condition in a population within a specified period of time. Although sometimes loosely expressed simply as the number of new cases during some time period, it is better expressed as a proportion or a rate with a denominator. Incidence proportion Incidence proportion (IP), also known as cumulative incidence, is defined as the probability that a particular event, such as occurrence of a particular disease, has occurred before a given time. It is calculated dividing the number of new cases during a given period by the number of subjects at risk in the population initially at risk at the beginning of the study. Where the period of time considered is an entire lifetime, the incidence proportion is called lifetime risk. For example, if a population initially contains 1,000 persons and 28 develop a condition since the disease first occurred until two years later, the cumulative incidence pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Breast
The breast is one of two prominences located on the upper ventral region of a primate's torso. Both females and males develop breasts from the same embryological tissues. In females, it serves as the mammary gland, which produces and secretes milk to feed infants. Subcutaneous fat covers and envelops a network of ducts that converge on the nipple, and these tissues give the breast its size and shape. At the ends of the ducts are lobules, or clusters of alveoli, where milk is produced and stored in response to hormonal signals. During pregnancy, the breast responds to a complex interaction of hormones, including estrogens, progesterone, and prolactin, that mediate the completion of its development, namely lobuloalveolar maturation, in preparation of lactation and breastfeeding. Humans are the only animals with permanent breasts. At puberty, estrogens, in conjunction with growth hormone, cause permanent breast growth in female humans. This happens only to a much ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sclera
The sclera, also known as the white of the eye or, in older literature, as the tunica albuginea oculi, is the opaque, fibrous, protective, outer layer of the human eye containing mainly collagen and some crucial elastic fiber. In humans, and some other vertebrates, the whole sclera is white, contrasting with the coloured iris, but in most mammals, the visible part of the sclera matches the colour of the iris, so the white part does not normally show while other vertebrates have distinct colors for both of them. In the development of the embryo, the sclera is derived from the neural crest. In children, it is thinner and shows some of the underlying pigment, appearing slightly blue. In the elderly, fatty deposits on the sclera can make it appear slightly yellow. People with dark skin can have naturally darkened sclerae, the result of melanin pigmentation. The human eye is relatively rare for having a pale sclera (relative to the iris). This makes it easier for one individual t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypogonadism
Hypogonadism means diminished functional activity of the gonads—the testes or the ovaries—that may result in diminished production of sex hormones. Low androgen (e.g., testosterone) levels are referred to as hypoandrogenism and low estrogen (e.g., estradiol) as hypoestrogenism. These are responsible for the observed signs and symptoms in both males and females. Hypogonadism, commonly referred to by the symptom "low testosterone" or "Low T", can also decrease other hormones secreted by the gonads including progesterone, DHEA, anti-Müllerian hormone, activin, and inhibin. Sperm development (spermatogenesis) and release of the egg from the ovaries (ovulation) may be impaired by hypogonadism, which, depending on the degree of severity, may result in partial or complete infertility. In January 2020, the American College of Physicians issued clinical guidelines for testosterone treatment in adult men with age-related low levels of testosterone. The guidelines are supported ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Obesity
Obesity is a medical condition, sometimes considered a disease, in which excess body fat has accumulated to such an extent that it may negatively affect health. People are classified as obese when their body mass index (BMI)—a person's weight divided by the square of the person's height—is over ; the range is defined as overweight. Some East Asian countries use lower values to calculate obesity. Obesity is a major cause of disability and is correlated with various diseases and conditions, particularly cardiovascular diseases, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis. Obesity has individual, socioeconomic, and environmental causes. Some known causes are diet, physical activity, automation, urbanization, genetic susceptibility, medications, mental disorders, economic policies, endocrine disorders, and exposure to endocrine-disrupting chemicals. While a majority of obese individuals at any given time are attemptin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mandible
In anatomy, the mandible, lower jaw or jawbone is the largest, strongest and lowest bone in the human facial skeleton. It forms the lower jaw and holds the lower teeth in place. The mandible sits beneath the maxilla. It is the only movable bone of the skull (discounting the ossicles of the middle ear). It is connected to the temporal bones by the temporomandibular joints. The bone is formed in the fetus from a fusion of the left and right mandibular prominences, and the point where these sides join, the mandibular symphysis, is still visible as a faint ridge in the midline. Like other symphyses in the body, this is a midline articulation where the bones are joined by fibrocartilage, but this articulation fuses together in early childhood.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, p. 59 The word "mandible" derives from the Latin word ''mandibula'', "jawbone" (literally "one used for chewing"), from '' mandere'' "to chew" and ''-bula'' (in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasal Bridge
The nasal bridge is the upper, bony part of the human nose, which overlies the nasal bones. Association with epicanthic folds Low-rooted nasal bridges are closely associated with epicanthic folds. A lower nasal bridge is more likely to cause an epicanthic fold, and vice versa. Dysmorphology A lower or higher than average nasal bridge can be a sign of various genetic disorders, such as fetal alcohol syndrome. A flat nasal bridge can be a sign of Down syndrome (Trisomy 21), Fragile X syndrome, 48,XXXY variant Klinefelter syndrome, or Bartarlla-Scott syndrome. An appearance of a widened nasal bridge can be seen with dystopia canthorum, which is a lateral displacement of the inner canthi of the eyes. from UTMB, Dept. of Otolaryngology. DATE: March 17, 2004. RESIDENT PHYSICIAN: Jing Shen. F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tall Stature
Human height or stature is the distance from the bottom of the feet to the top of the head in a human body, standing erect. It is measured using a stadiometer, in centimetres when using the metric system or SI system, or feet and inches when using United States customary units or the imperial system. In the early phase of anthropometric research history, questions about height techniques for measuring nutritional status often concerned genetic differences. Height is also important because it is closely correlated with other health components, such as life expectancy. Studies show that there is a correlation between small stature and a longer life expectancy. Individuals of small stature are also more likely to have lower blood pressure and are less likely to acquire cancer. The University of Hawaii has found that the "longevity gene" FOXO3 that reduces the effects of aging is more commonly found in individuals of small body size. Short stature decreases the risk of venous ins ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (biology), morphology or physical form and structure, its Developmental biology, developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the Gene expression, expression of an organism's genetic code, or its genotype, and the influence of environmental factors. Both factors may interact, further affecting phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called Polymorphism (biology), polymorphic. A well-documented example of polymorphism is Labrador Retriever coat colour genetics, Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and then again i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigantism
Gigantism ( el, γίγας, ''gígas'', " giant", plural γίγαντες, ''gígantes''), also known as giantism, is a condition characterized by excessive growth and height significantly above average. In humans, this condition is caused by over-production of growth hormone in childhood, resulting in people up to in height. It is a rare disorder resulting from increased levels of growth hormone before the fusion of the growth plate which usually occurs at some point soon after puberty. This increase is most often due to abnormal tumor growths on the pituitary gland. Gigantism should not be confused with acromegaly, the adult form of the disorder, characterized by somatic enlargement specifically in the extremities and face. Cause Gigantism is characterized by an excess of growth hormone (GH). The excess of growth hormone that brings about gigantism is virtually always caused by pituitary growths (adenomas). These adenomas are on the anterior pituitary gland. They can also c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
