Barr Body Analysis Buccal Smear for Staining Sex Chromatin Mass

Norm of Barr Body Analysis Buccal Smear for Staining Sex Chromatin Mass

	Number of Barr Bodies
Normal female (XX)	1
Normal male (XY)	0
Turner's syndrome (female) (XO)	0
Klinefelter's syndrome (male) (XXY)	1
Klinefelter's syndrome (male) (48,XXXY)	2
Klinefelter's syndrome (male) (49,XXXYY)	2
Klinefelter's syndrome (male) (49,XXXXY)	3

 

Usage of Barr Body Analysis Buccal Smear for Staining Sex Chromatin Mass

Screening for sex chromosome abnormalities.

 

Description of Barr Body Analysis Buccal Smear for Staining Sex Chromatin Mass

A Barr body, or sex chromatin body, is a tightly coiled X chromosome lying against the nuclear membrane of female cells or any cell with more than one X chromosome. It appears as a dark-staining body in the shape of a half-moon and is absent in male cells. Barr bodies are believed to function in early embryonic development and later become inactivated to maintain gene balance of Xs to autosomes. The number of Barr bodies in a client is one less than the number of Xs.

 

Professional Considerations of Barr Body Analysis Buccal Smear for Staining Sex Chromatin Mass

Consent form NOT required.
Preparation

1. Rinse the mouth with mouthwash.
2. Obtain a metal spatula, saline, two slides, and preservative.

 

Procedure

1. Gently scrape the buccal mucosa with the metal spatula dipped in saline.
2. Clean the spatula and repeat the procedure gently but firmly.
3. Smear the material on the two slides and place them in the preservative.

 

Postprocedure Care

1. Label the container of the slides with the client's name, the date, and the contents.

 

Client and Family Teaching

1. Refer the client with abnormal results for genetic counseling.

 

Factors That Affect Results

1. None known.

 

Other Data

1. Barr bodies do not give any information about Y chromosomes.
2. Human chromosome analysis, rather than buccal smears, should be used for evaluations of newborns with ambiguous genitalia.