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Genetics and Birth Defects Glossary

Terms used to explain Genetics and Birth Defects can sometimes be confusing. To help you fully understand the articles and features related to this very important health topic, we have compiled a glossary of terms that can help.

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Function: abbreviation
attention-deficit/hyperactivity disorder


Pronunciation: \ˈak-nē\

Function: noun
: a disorder of the skin caused by inflammation of the skin glands and hair follicles; specif: a form found chiefly in adolescents and marked by pimples esp. on the face


Pronunciation: \ˈaf-tər-ˌbərth\

Function: noun
: the placenta and fetal membranes that are expelled after delivery —called also secundines


Pronunciation: \ˈal-ər-jē\

Function: noun
pl -gies

1: altered bodily reactivity (as hypersensitivity) to an antigen in response to a first exposure <his bee-venom allergy may render a second sting fatal>
2: exaggerated or pathological reaction (as by sneezing, respiratory embarrassment, itching, or skin rashes) to substances, situations, or physical states that are without comparable effect on the average individual
3: medical practice concerned with allergies


Pronunciation: \ə-ˌpen-də-ˈsīt-əs\

Function: noun
: inflammation of the vermiform appendix —called also epityphlitis


Pronunciation: \ˈo-ˌtiz-əm\

Function: noun

1: a developmental disorder that appears by age three and that is variable in expression but is recognized and diagnosed by impairment of the ability to form normal social relationships, by impairment of the ability to communicate with others, and by stereotyped behavior patterns esp. as exhibited by a preoccupation with repetitive activities of restricted focus rather than with flexible and imaginative ones


Pronunciation: \-ˌwet-iŋ\

Function: noun
: enuresis esp. when occurring in bed during sleep

Braxton-Hicks Contractions

Brax*ton–Hicks contractions
Pronunciation: \ˌbrak-stən-ˈhiks-\

Function: noun plural
: relatively painless nonrhythmic contractions of the uterus that occur during pregnancy with increasing frequency over time but are not associated with labor

Cesarean Section

cesarean section
Function: noun
: surgical incision of the walls of the abdomen and uterus for delivery of offspring

Cradle Cap

cradle cap
Function: noun
: a seborrheic condition in infants that usu. affects the scalp and is characterized by greasy gray or dark brown adherent scaly crusts

Diaper Rash

diaper rash
Function: noun
: skin irritation of the diaper-covered area and usu. the buttocks of an infant esp. from exposure to feces and urinary ammonia


Pronunciation: \dī-ˈlā-shən\

Function: noun

1: the state of being dilated : see: dilatation
2: the action of stretching or enlarging an organ or part of the body <cervical dilation> <dilation of the pupil with atropine>


Pronunciation: \dis-ˈlek-sē-ə\

Function: noun
: a variable often familial learning disability involving difficulties in acquiring and processing language that is typically manifested by a lack of proficiency in reading, spelling, and writing

Ectopic Pregnancy

ectopic pregnancy
Function: noun

: gestation elsewhere than in the uterus (as in a fallopian tube or in the peritoneal cavity) —called also ectopic gestation, extrauterine gestation, extrauterine pregnancy


Pronunciation: \ˌep-i-ˈd(y)ur-əl\

Function: adjective
: situated upon or administered or placed outside the dura mater <epidural[1] anesthesia> <an epidural[1] abscess>


Pronunciation: \ˈflu(-ə)r-ˌīd\

Function: noun

1: a compound of fluorine with a more electropositive element or radical
2: the monovalent anion of fluorine


Pronunciation: \lak-ˈtā-shən\

Function: noun

1: the secretion and yielding of milk by the mammary gland
2: one complete period of lactation extending from about the time of parturition to weaning

Learning Disability

learning disability
Function: noun
: any of various disorders (as dyslexia or dysgraphia) that interfere with an individual's ability to learn resulting in impaired functioning in verbal language, reasoning, or academic skills (as reading, writing, and mathematics) and are thought to be caused by difficulties in processing and integrating information


Pronunciation: \mis-ˈkar-ij\

Function: noun
: spontaneous expulsion of a human fetus before it is viable and esp. between the 12th and 28th weeks of gestation compare abortion 1a

Morning Sickness

morning sickness
Function: noun
: nausea and vomiting that occurs typically in the morning esp. during the earlier months of pregnancy


Pronunciation: \-ˈdänt-iks\

Function: n pl but sing in constr

1: a branch of dentistry dealing with irregularities of the teeth and their correction (as by means of braces)
2: the treatment provided by an orthodontist


Function: noun
: a specialist in pediatrics —called also pediatrist


Pronunciation: \plə-ˈsent-ə\

Function: noun
pl -centas
or -cen*tae
Pronunciation: \-ˈsent-(ˌ)ē\

: the vascular organ in mammals except monotremes and marsupials that unites the fetus to the maternal uterus and mediates its metabolic exchanges through a more or less intimate association of uterine mucosal with chorionic and usu. allantoic tissues permitting exchange of material by diffusion between the maternal and fetal vascular systems but without direct contact between maternal and fetal blood and typically involving the interlocking of fingerlike vascular chorionic villi with corresponding modified areas of the uterine mucosa see abruptio placentae


Pronunciation: \-ˈtərm\

Function: adjective
: of, relating to, being, or born by premature birth <preterm infants> <a preterm delivery> <preterm labor>


Pronunciation: \ˈpyü-bərt-ē\

Function: noun
pl -ties

1: the condition of being or the period of becoming first capable of reproducing sexually marked by maturing of the genital organs, development of secondary sex characteristics, and in humans and the higher primates by the first occurrence of menstruation in the female
2: the age at which puberty occurs being typically between 13 and 16 years in boys and 11 and 14 in girls and often construed legally as 14 in boys and 12 in girls


Pronunciation: \rī-ˈnīt-əs\

Function: noun
pl -nit*i*des
Pronunciation: \-ˈnit-ə-ˌdēz\
: inflammation of the mucous membrane of the nose marked esp. by rhinorrhea, nasal congestion and itching, and sneezing; also: any of various conditions characterized by rhinitis see allergic rhinitis rhinitis medicamentosa rhinitis sicca vasomotor rhinitis


Function: abbreviation
sudden infant death syndrome

Spinal Anesthesia

spinal anesthesia
Function: noun
: anesthesia produced by injection of an anesthetic into the subarachnoid space of the spine


Pronunciation: \ˈtet-ən-əs, ˈtet-nəs\

Function: noun

1 a: an acute infectious disease characterized by tonic spasm of voluntary muscles and esp. of the muscles of the jaw and caused by the specific toxin produced by a bacterium of the genus Clostridium (C. tetani) which is usu. introduced through a wound compare lockjaw
b: see: tetanus bacillus
2: prolonged contraction of a muscle resulting from a series of motor impulses following one another too rapidly to permit intervening relaxation of the muscle


Pronunciation: \ˈəl-trə-ˌsaund\

Function: noun

1: vibrations of the same physical nature as sound but with frequencies above the range of human hearing compare infrasound
2: the diagnostic or therapeutic use of ultrasound and esp. a noninvasive technique involving the formation of a two-dimensional image used for the examination and measurement of internal body structures and the detection of bodily abnormalities —called also echography, sonography, ultrasonography
3: a diagnostic examination using ultrasound

Umbilical Hernia

umbilical hernia
Function: noun
: a hernia of abdominal viscera at the navel —called also exomphalos

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© 2011 Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Inc.

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