II. Definitions

  1. Buccal Smear (or Sex Chromatin Test)
    1. Microscopy of cheek cell scraping
    2. Presence of barr bodies suggests 2 X-Chromosomes
  2. Barr Body
    1. Inactivated X-Chromosome in each cell of a female
    2. Seen as an intracellular dark spot on microscopy

III. History

  1. Barr Body first identified by Dr. Murray Barr in 1949
  2. Mary Lyon suggested etiology and named it Barr Body

IV. Physiology

  1. All cells in female, turn off 1 of 2 X-Chromosomes
  2. Occurs on day 16 of Embryonic development
  3. Each cell child inherits same inactivated X-Chromosome

V. Indications

  1. Replaced by karyotype for full chromosomal mapping
  2. Previously used to evaluate abnormal Sexual Development
    1. Delayed Menarche
    2. Delayed Puberty

VI. Procedure

  1. Gently scrape inside of cheek
    1. May use wooden Tongue blade or toothpick
  2. Spread sample onto slide into drop of saline
  3. Dry slide and stain with methylene blue 0.3%

VII. Interpretation

  1. Barr Body: Crumpled dark Chromosome seen in cell
    1. Suggests normal female karyotype 46XX

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Related Studies

Ontology: Sex Chromatin (C0036867)

Definition (GO) Chromatin that is part of a sex chromosome. [GOC:dos, ISBN:0198506732]
Definition (NCI) The inactive, condensed X chromosome in a female somatic cell.
Definition (MSH) In the interphase nucleus, a condensed mass of chromatin representing an inactivated X chromosome. Each X CHROMOSOME, in excess of one, forms sex chromatin (Barr body) in the mammalian nucleus. (from King & Stansfield, A Dictionary of Genetics, 4th ed)
Definition (GO) A structure found in a female mammalian cell containing an unpaired X chromosome that has become densely heterochromatic, silenced and localized at the nuclear periphery. [GOC:hjd]
Concepts Cell Component (T026)
MSH D012728
SnomedCT 58348001
LNC LP18339-9, MTHU004078, LA11179-1
English Barr Bodies, Bodies, Barr, Chromatin, Sex, Chromatins, Sex, Sex Chromatin, Sex Chromatins, sex chromatin, Barr chromatin body, barr bodies, chromatin sex, barr body, Barr bodies, Barr body, Sex chromatin, Sex chromatin (substance), Barr Body
French Corpuscules de Barr, Chromatine sexuelle
Swedish Könskromatin
Czech sexchromatin
Finnish Barrin kappale
Italian Corpi di Barr, Cromatina sessuale
Latvian Dzimumhromatīns
Polish Ciałko Barra, Chromatyna płciowa
Japanese クロマチン-性, 性クロマチン, バール小体, 性染色質, 染色質-性
Norwegian Kjønnskromatin, Barr-legemer, Barr-inklusjonslegemer
Spanish cromatina sexual (sustancia), cromatina sexual, cuerpo de cromatina de Barr, Corpusculos de Barr, Cromatina Sexual
German Chromatin, Geschlechts-, Geschlechtschromatin, Barr-Körperchen
Dutch Barr-lichaampjes, Chromatine, sekse-, Seksechromatine
Portuguese Corpos de Barr, Cromatina Sexual

Ontology: buccal smear biopsy procedure (C0581714)

Concepts Diagnostic Procedure (T060)
SnomedCT 31402005, 303995001
LNC LP7093-0, MTHU007944
Italian Striscio orale, Striscio buccale
Dutch uitstrijkje wangslijmvlies, wangslijmvliesuitstrijkje
Japanese 頬部スミア, ホホブスミア, キョウブスミア
Czech Stěr z bukální sliznice
English Smear buccal, buccal smears, buccal smear, Buccal smear for Barr bodies, Buccal smear for Barr bodies (procedure), Buccal smear, Buccal smear procedure, Buccal smear procedure (procedure), Buccal smear for Barr bodies (procedure) [Ambiguous], buccal smear biopsy procedure
Hungarian Buccalis kenet
Spanish extendido bucal para detección de corpúsculos de Barr, extendido bucal para detección de corpúsculos de Barr (procedimiento), frotis bucal, extendido bucal para detección de corpúsculos de Barr (concepto no activo), procedimiento de extendido de material del carrillo, procedimiento de extendido yugal (procedimiento), procedimiento de extendido yugal, procedimiento de frotis yugal, Frotis bucal
Portuguese Esfregaço bucal
French Frottis buccal
German Mundabstrich