The name is absent



18


Stata Technical Bulletin


STB-57


Options

label(genotypes) requests that labels are used in the output of the genotype frequency table.

binvar requests that the standard errors from a binomial distribution are reported for each allele frequency. These standard
errors are calculated under the assumption that the population is under HWE. By default, standard errors that do not require
this assumption are reported.

Remarks

genhwcci performs asymptotic tests for HWE for genotypic counts of cases given the controls are under HWE. It also
estimates the disequilibrium coefficient (D) and its standard error for genotypic counts of cases and controls, separately. See
Methods and formulas for details.

Example

Helzlsouer et al. 1998 conducted a case-control study for the association of CYP17 polymorphism and breast cancer, in
which 109 cases and 113 controls were collected. We test the hypotheses whether the cases and controls are under
HWE, separately.
Given the controls are under
HWE, we test whether the cases are under HWE. An immediate command is used for testing the
HWE.

. genhwcci 41 47 21 37 58 18, label(AA AB BB)

Genotype          Case         Control           Total

------------+-------------------------------+-------------

AA I              41                 37   I              78

AB I              47                 58   I             105

BB I              21                 18   I              39

------------+-------------------------------+-------------
total I            109               113  I            222

Case

Allele     Case

Frequency

Std. Err.

A I        129

B I         89

0.5917

0.4083

0.0350

0.0350

————————————⅛-———————————

total I       218

1.0000

Estimated disequilibrium coefficient

Hardy-Weinberg Equilibrium Test :

Pearson chi2 (1) = 1.261
likelihood-ratio chi2 (1) = 1.258
Exact significance prob =

Control

Allele Control     Frequency

(D) =

SE =

Pr=
Pr=

=   0.0260

=   0.0232

0.2614

0.2620

0.3204

Std. Err.

A I        132

B I         94

0.5841

0.4159

0.0318

0.0318

——————————+—-----------

total I       226

1.0000

Estimated disequilibrium coefficient (D) =

SE =

Hardy-Weinberg Equilibrium Test :

Pearson chi2 (1) = 0.360 Pr=
likelihood-ratio chi2 (1) = 0.361 Pr=
Exact significance prob =

Test HO: cases under HWE: (given controls
likelihood-ratio chi2 (2) =    1.285 Pr=

= -0.0137

=   0.0227

0.5487

0.5481

0.6983

under HWE)
0.5260

The label () option is used to label the genotypes in the table. The order of the genotypes is in the same order as given in the
syntax.

For this example, there is no significant evidence that the genotypic counts of cases and controls are not under HWE. Even
given the controls are under
HWE, there is still no significant evidence that the cases are not under HWE.



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