Human health and medicine

Greig cephalopolysyndactyly-contiguous gene syndrome

GCPS-CGS is a rare chromosomal deletion syndrome: microdeletions over 1 Mb at 7p encompassing GLI3 cause Greig cephalopolysyndactyly features plus intellectual disability, seizures, and corpus callosum defects.

Grepafloxacin

Grepafloxacin (OPC-17116, Raxar/Vaxar) was a third-generation fluoroquinolone antibiotic by Otsuka and Glaxo Wellcome, approved 1997 for bronchitis and pneumonia, withdrawn worldwide in 1999 for QTc prolongation and cardiac deaths.

Greying of hair

Greying of hair (canities) is age-related loss of melanin in hair follicles, typically starting in the 30s-40s; premature graying is linked to smoking, vitamin deficiencies, and stress, with no established medical reversal treatment.

GRFoma

GRFoma (GRF tumor, GHRHoma) is a rare neuroendocrine tumor, mostly lung (54%) or pancreas (30%), that ectopically secretes GHRH, causing acromegaly with pituitary hyperplasia; diagnosed by plasma GHRH above 250-300 ng/L, treated by resection or somatostatin analogs.

Grhadhumadi lepa

Grhadhumadi lepa (Gṛhadhūmādi lepa, गृहधूमादि लेप), also Grihadhoomadi Choornam, is a classical Ayurvedic external paste of kitchen soot, vacha, kushta, dill seed, and two turmerics from Ashtanga Hridayam 22:36, used mainly for gouty arthritis (Vatarakta) and wounds.

GRID® study

The GRID study, Decipher Genomics Resource for Intelligent Discovery, is an observational registry started in 2015 that links Decipher prostate cancer test RNA data with patient outcomes.

Grimace scale

A grimace scale is an observational pain measure scoring facial expressions in nonverbal subjects like laboratory animals; the first, the Mouse Grimace Scale, was described in 2010.

Gripe water

Gripe water, an herbal liquid supplement for infant colic and gas, originated with William Woodward's 1851 Nottingham formula; no randomized trial evidence supports it, and US products are sold as unregulated supplements with several recalls.

Griscelli syndrome

Griscelli syndrome, also called partial albinism-immunodeficiency syndrome, is a rare autosomal recessive disorder with silvery-gray hair and skin hypopigmentation. Three types: MYO5A (neurologic), RAB27A (immunodeficiency with HLH), MLPH (isolated).

Grisel syndrome

Grisel syndrome, or nontraumatic atlantoaxial rotatory subluxation, is a rare pediatric condition causing painful torticollis after head and neck infections or ENT procedures such as adenoidectomy; treated conservatively in most cases.

Griseofulvin

Griseofulvin, a fungistatic antibiotic from Penicillium griseofulvum (discovered 1939, launched 1959), treats dermatophyte infections by binding microtubular proteins; first oral antifungal, WHO essential drug.

Groin

The groin, known in anatomy as the inguinal region, is the junction between the torso and the thigh, containing the inguinal canal through which hernias commonly occur.

Groin hernia repair

Groin hernia repair is surgery to close a groin defect, usually an inguinal hernia, most often with mesh; over 800,000 repairs are done yearly in the United States.

Groote Schuur Hospital

Groote Schuur Hospital (GSH), Cape Town's premier public tertiary academic hospital and UCT's main teaching hospital, opened 1938; site of the world's first human heart transplant by Christiaan Barnard on 3 December 1967.

Grooved Pegboard Test

The Grooved Pegboard Test is a neuropsychological test of fine motor speed and dexterity in which 25 keyed pegs are inserted one hand at a time.

Gross examination

Gross examination, or grossing, is the bare-eye inspection, description, measurement, and sampling of surgical specimens in a pathology laboratory before microscopic processing, so the right tissue reaches the histologist.

Gross Motor Function Classification System

The Gross Motor Function Classification System, or GMFCS, is a five-level scale classifying how children with cerebral palsy sit and walk, introduced by Robert Palisano and colleagues in 1997.

Gross total resection

Gross total resection (GTR) is the complete removal of all macroscopically visible tumor during surgery, assessed by postoperative MRI within 48 hours and linked to longer survival in glioblastoma.

Ground-glass opacity

Ground-glass opacity (GGO), also called ground-glass nodule when focal, is a hazy CT lung finding with visible vessels, caused by infection (including COVID-19), inflammation, hemorrhage, or adenocarcinoma-spectrum cancer; managed by multi-year surveillance, PET having low sensitivity.

Group 5 pulmonary hypertension

Group 5 pulmonary hypertension is the residual classification category for pulmonary hypertension with unclear or multifactorial mechanisms, including sarcoidosis, hematologic disorders, and chronic renal failure.

Group C nerve fiber

Group C nerve fibers (C fibers, group IV) are unmyelinated, 0.2-1.5 micrometer peripheral axons conducting at 0.5-2 m/s, carrying slow burning pain, temperature, and itch, distinguished from myelinated A fibers.

Group Practice

Group practice: three or more physicians in a legally recognized entity sharing space, equipment, personnel, records, and income distribution. Covers forms, history, quality evidence versus solo practice, and US trends.

Group sequential design

A group sequential design is a clinical trial design allowing interim analyses with early stopping for efficacy, futility, or safety at a controlled error rate.

Growing teratoma syndrome

Growing teratoma syndrome (GTS): rare enlargement of mature teratoma masses during or after chemotherapy for non-seminomatous germ cell tumors despite normalized markers; described by Logothetis in 1982; treated by complete surgical resection.

Growth chart

Growth charts are percentile curves tracking children's weight, length, head circumference, and BMI by age and sex. Key sets are the 2006 WHO Child Growth Standards (0-59 months, MGRS, six countries) and the 2000 CDC reference charts (US, 1963-1994).

Growth cone

Growth cone: the motile, sensory tip of a growing axon, first described by Cajal in 1890, that steers axon pathfinding via actin-driven filopodia and attractive or repulsive guidance cues such as netrins and semaphorins.

Growth delay due to insulin-like growth factor type 1 deficiency

Growth delay due to IGF-1 deficiency (ORPHA:73272, OMIM 608747), also called growth delay-deafness-intellectual disability syndrome: an autosomal recessive IGF1-gene disorder with intrauterine and postnatal growth retardation, sensorineural deafness, and intellectual deficit; under 1 per million, about four reported cases.

Growth delay-hydrocephaly-lung hypoplasia syndrome

Growth delay-hydrocephaly-lung hypoplasia syndrome, or Game-Friedman-Paradice syndrome (ORPHA:3035, OMIM 236640), is an ultra-rare autosomal recessive disorder seen in four siblings, marked by fetal growth retardation, hydrocephalus with patent aqueduct of Sylvius, pulmonary hypoplasia, omphalocele, and limb anomalies.

Growth hormone

Growth hormone (somatotropin, GH) is a pituitary peptide hormone acting via the GH receptor and IGF-1; treats growth hormone deficiency, banned in sport (WADA S2), and not supported as anti-aging or performance-enhancing therapy.