Savage et al developed a score for identifying patients with the growth hormone insensitivity syndrome (Laron Syndrome). The authors are from multiple universities in the United States and Europe.
Parameters:
(1) basal serum growth hormone in µg/L
(2) serum IGF-I in µg/L
(3) IGF-I generation test (after administration of exogenous growth hormone)
(4) height expressed in standard deviation (Z) score
(5) percent growth hormone binding protein (based on binding uptake of I125-GH)
|
Parameter |
Finding |
Points |
|
basal serum growth hormone |
< 5 µg/L |
0 |
|
|
>= 5 µg/L |
1 |
|
serum IGF-I |
> 50 µg/L |
0 |
|
|
<= 50 µg/L |
1 |
|
IGF-I generation |
>= 20% |
0 |
|
|
< 20% |
1 |
|
height |
>= -3 standard deviations below mean |
0 |
|
|
< -3 standard deviations below mean |
1 |
|
percent GH binding protein |
>= 10% |
0 |
|
|
< 10% |
1 |
where:
• The intra-assay variation for the IGF-I assay was 10%. Two times this is 20% (see column 2 page 1467).
• The different assays used are listed on page 1466.
• My guess is that the percent binding protein is the amount of radioactive GH that is taken up by the binding protein, indicating that the binding sites are saturated with endogenous GH.
total score =
= SUM(points for all 5 parameters)
Interpretation:
• minimum score: 0
• maximum score: 5
• The higher the score the greater the likelihood of the growth hormone insensitivity syndrome.
• Of 27 patients with definite GHIS, 44% had a score of 5, 33% had a score of 4, and the remainder had a score of 2 or 3 (page 1466). Using this as a guide the following table is used in the implementation.
|
Total Score |
GH Insensitivity |
|
5 |
definite |
|
4 |
probable |
|
2 or 3 |
possible |
|
0 or 1 |
unlikely |
Specialty: Endocrinology, Clinical Laboratory
