| neural tube defect | <neurology, paediatrics> Abnormal development during embryonic life of the neural tube producing congenital malformations of the nervous system due to closure failure of the neural tube. The structure gives rise to the central nervous system (the brain and spinal cord), and failure to close results in anencephaly (absence of the cranial vault and absence of most or all of the cerebral hemispheres of the brain) and spina bifida or meningomyelocele (open spina with exposure and protusion of the spinal cord). The risk of neuroal tube defects can be decreased by the mother taking folic acid during pregnancy. (04 Jul 1999) |
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| defect | 1. Want or absence of something necessary for completeness or perfection; deficiency; opposed to superfluity. "Errors have been corrected, and defects supplied." (Davies) 2. Failing; fault; imperfection, whether physical or moral; blemish; as, a defect in the ear or eye; a defect in timber or iron; a defect of memory or judgment. "Trust not yourself; but, your defects to know, Make use of every friend any every foe." (Pope) "Among boys little tenderness is shown to personal defects." (Macaulay) Synonym: Deficiency, imperfection, blemish. See Fault. Origin: L. Defectus, fr. Deficere, defectum, to desert, fail, be wanting; de- + facere = to make, do. See Fact, Feat, and cf. Deficit. Source: Websters Dictionary (01 Mar 1998) |
| defect, atrial septal | A hole in the septum, the wall, between the atria, the upper chambers of the heart. Commonly called an ASD. ASDs are a major class of congenital cardiac malformation. (12 Dec 1998) |
| defect, enzyme | An abnormality in the protein (enzyme) important in catalyzing a normal biochemical reaction in the body. Disorders result from a deficiency (or functional abnormality) of an enzyme. Archibald Garrod in 1902 was the first to attribute a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as phenylketonuria (PKU) and galactosaemia, an error in the handling (metabolism) of the sugar galactose. (12 Dec 1998) |
| defect, ventricular septal | Hole in the interventricular septum, the wall between the ventricles (lower chambers of the heart). Commonly called a VSD. VSDs are a common class of heart deformity present at birth (congenital cardiac malformation). (17 Dec 1998) |
| iodide transport defect | See: familial goiter. (05 Mar 2000) |
| iodotyrosine deiodinase defect | See: familial goiter. (05 Mar 2000) |
| osteoporotic marrow defect | Focal osteoporotic bone marrow defect of the jaw; a focal radiolucent defect composed of normal marrow. (05 Mar 2000) |
| Eisenmenger's defect | The combination of ventricular septal defect with pulmonary hypertension and consequent right-to-left shunt through the defect, with or without an associated overriding aorta. Synonym: Eisenmenger's defect, Eisenmenger's disease, Eisenmenger's tetralogy. (05 Mar 2000) |
| endocardial cushion defect | <radiology> Persistence of primitive atrioventricular canal and anomalies of AV valves associated with: Down syndrome: in 25% of Trisomy 21 an ECD is present; in 45% of ECD Trisomy 21 is present, asplenia/polysplenia types: complete (AV canal), partial findings: gooseneck deformity on angiogram, increased pulmonary vascularity, enlarged pulmonary artery, enlarged RV, LV, RA; normal LA (secondary to atrial septal defect) (12 Dec 1998) |
| enzyme defect | A disorder resulting from a deficiency (or functional abnormality) of an enzyme. In 1902 Archibald Garrod first attributed a disease to an enzyme defect: an inborn error of metabolism. Today, newborns are routinely screened for certain enzyme defects such as PKU (phenylketonuria) and galactosaemia, an error in the handling (metabolism) of the sugar galactose. (12 Dec 1998) |
| fibrous cortical defect | A common 1 to 3 cm defect in the cortex of a bone, most commonly the lower femoral shaft of a child, filled with fibrous tissue. Nonosteogenic or nonossifying fibroma by convention refers to lesions greater than 3 cm in diameter. See: nonossifying fibroma. Synonym: nonosteogenic fibroma. (05 Mar 2000) |
| lambdoid suture defect | <radiology> Well-defined lucent lesion, classically unilateral, associated with neurofibromatosis (12 Dec 1998) |
| luteal phase defect | Inadequate function of the corpus luteum that may prevent a fertilized egg from implanting in the uterus or may lead to early pregnancy loss. (09 Oct 1997) |
| reflux, oesophageal | A condition wherein stomach contents regurgitate or back up (reflux) into the oesophagus (a long cylindrical tube that transports food from the mouth to the stomach). The food in the stomach is partially digested by stomach acid and enzymes. Normally, the partially digested acid content in the stomach is delivered by the stomach muscle into the small intestine for further digestion. In oesophageal reflux, stomach acid content refluxes backwards up into the oesophagus, occasionally reaching the breathing passages, causing inflammation and damage to the oesophagus, as well as to the lung and larynx (the voice box). The overall process is medically termed gastroesophageal reflux disease (gerd). 10% of patients with gerd develop a barrett's oesophagus which can increase the risk of cancer of the oesophagus. (12 Dec 1998) |