Table 4.
Established Genetic Defects Resulting in Primary IGFD or IGF Resistance
| GHR | STAT5B | IGF1 | IGFALS | IGF1R | Bioinactive GH | |
|---|---|---|---|---|---|---|
| Postnatal growth failure | +++ | +++ | +++ | +/− | ++ | ++ |
| IUGR | +/− | +/− | ++ | +/− | ++ | +/− |
| Midfacial hypoplasia | ++ | ++ | − | − | − | +/− |
| Other facial dysmorphism | − | − | ++ | − | +/− | − |
| Microcephaly | − | − | ++ | − | +/− | − |
| Deafness | − | − | +/− | − | − | − |
| Mental retardation | − | − | ++ | − | +/− | − |
| Immunodeficiency | − | ++ | − | − | − | − |
| Serum GH | ↑ | ↑ | ↑ | nl | ↑/nl | ↑ |
| Serum GHBP | ↓/nl/↑ | nl | nl | nl | nl | nl |
| Serum IGF-1 | ↓↓ | ↓↓ | ↑/nl/↓ | ↓↓ | ↑/nl | ↓↓ |
| Serum IGFBP-3 | ↓↓ | ↓↓ | ↑/nl | ↓↓ | ↑/nl | ↓↓ |
| Serum ALS | ↓↓ | ↓↓ | nl | ↓↓↓ | nl | ↓↓ |
| Serum PRL | nl | ↑ | nl | nl | nl | nl |
Abbreviations: IGFALS, IGF-1 acid labile subunit gene; IGF1R, IGF-1 receptor gene; IUGR, intrauterine growth retardation; GHBP, GH binding protein; nl, normal. [Adapted from P. F. Backeljauw et al: Disorders of growth. In: Sperling MA, ed. Textbook of Pediatric Endocrinology (in press).] ++, present; −, absent; +/−, variably present; arrow pointing up, increased; arrow pointing down, decreased (the number of arrows indicates the degree of deviation).