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Open Angle Glaucoma (OAG) Evaluation Using Family Score

Purpose: To evaluate a patient with open-angle glaucoma for a genetic basis using the Family Score.

Description

Hulsman et al used the Family Score (FS) of Houlwing-Duistermaat and Van Houwelingen to evaluate a patient for open angle glaucoma. This can help identify the degree of genetic risk in the patient's family. The authors are from multiple ophthalmic institutes in Amsterdam and Rotterdam in the Netherlands.


family score =

= 10 * SUM((factor relative 1)……(factor relative N))

 

factor for relative =

= ((observed diseased status) - (expected value based on age and gender)) * (kinship coefficient)

 

Disease Status

Points

affected

1

not affected

0

 

 

 

Prevalence of Definite Open Angle Glaucoma in Cohort of 6,281 Independently Living Subjects

Age

Male

Female

< 55

0

0

55 - 59

0.002

0

60 - 64

0.006

0.001

65 - 69

0.008

0.009

70 - 74

0.013

0.011

75 - 79

0.019

0.006

>= 80

0.036

0.013

from Table 1, page 1728

 

 

Kinship

Coefficient

sibling

0.25

half-sibling

0.125

children

0.25

from page 1727; parents and other relatives not scored

 

where:

• The prevalence value for women 75-79 years of age seems out of pattern for the other ages. The patients listed as probable OAG also seemed out of pattern.

• The family score can also be calculated based on prevalence of both definite and probable open-angle glaucoma. These values are listed in Table 1 on page 1728.

 

Interpretation:

• A positive score indicates a genetic risk in the family for open-angle glaucoma.

• A score of 0 is indeterminate.

• A negative score indicates that genetic risk for the family is low.

• The odds ratio for the family score based on definitely affected relatives was 3.3 (see Table 4, page 1729).

 

Limitations:

• A small or young relative pool provides little information on genetic risk.


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Specialty

Objective

ICD-10