Craniofacial growth in short children born small for gestational age: effect of growth hormone treatment
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R van Erum1, M Mulier, C Carels
1School of Dentistry, Department of Orthodontics, University Hospital St. Rafaël, Leuven, Belgium.
Insights
High-dose growth hormone (GH) therapy in children born small for gestational age (SGA) accelerates craniofacial growth, particularly in the mandible and cranial base. However, it does not fully normalize facial proportions after two years of treatment.
Area of Science:
- Pediatric Endocrinology
- Craniofacial Biology
- Growth Hormone Therapy
Background:
- Children born small for gestational age (SGA) often exhibit delayed linear growth and craniofacial development.
- The long-term effects of growth hormone (GH) therapy on craniofacial growth in SGA children require further elucidation.
Purpose of the Study:
- To evaluate the impact of high-dose GH treatment on craniofacial growth in pre-pubertal children born SGA.
- To assess changes in specific craniofacial parameters and overall facial proportions.
Main Methods:
- A 2-year study involving 21 pre-pubertal, non-GH-deficient children born SGA, randomly assigned to GH treatment (0.2 or 0.3 IU/kg daily) or no treatment.
- Annual evaluation of craniofacial growth using standardized measurements.
- Analysis of angular and linear measurements, including SNB and ANB angles, cranial base length, and mandibular length.
Main Results:
- GH treatment significantly accelerated growth in posterior total facial height, cranial base length, and mandibular length.
- The mandibular length increase led to a greater SNB angle, indicating mandibular advancement.
- Despite accelerated growth, craniofacial size and mandibular position relative to the cranial base were not normalized in most treated children.
- No disproportional growth patterns were observed after 2 years of GH therapy.
Conclusions:
- Short pre-pubertal SGA children present with delayed linear craniofacial growth and a retrognathic mandible.
- High-dose GH therapy promotes craniofacial catch-up growth, especially in cartilaginous areas, leading to a less convex facial profile.
- Two years of GH treatment improves some craniofacial dimensions but does not fully normalize proportions in SGA children.
Abstract:
The effects of growth hormone (GH) therapy in children have yet to be completely catalogued. In the present study, the effect of high-dose GH treatment on craniofacial growth was evaluated once yearly in 21 pre-pubertal, non-GH-deficient children born small for gestational age. These children were randomly allocated to be either untreated or treated with GH at a daily subcutaneous dose of 0.2 or 0.3 IU/kg for 2 yrs. The group consisted of 12 girls and 9 boys with a mean age of 5.1 yr (range, 2 to 8 yr), bone age of 3.4 yr, and height SDS of -3.6. At the start of the study, all children showed an overall delay of craniofacial growth. This cohort of short children born small for gestational age showed a small SNB angle and a large ANB angle; all other angular measurements were within normal range. GH treatment accelerated growth in several craniofacial components, especially the posterior total facial height, the cranial base length, and the overall mandibular length. The increase of the mandibular length increased the SNB angle; no other angular measurements were affected. Age at start of treatment differently influenced the increase in posterior and total cranial base length, the increase in mandibular corpus length, and the position of the mandible in relation to the cranial base. Although GH treatment for 2 yrs led to a craniofacial growth acceleration, the position of the mandible in relation to the cranial base and the craniofacial size in lateral aspect were not normalized in the majority of the GH-treated children. No signs of disproportional growth were evidenced after 2 yrs of high-dose GH treatment. In conclusion, short pre-pubertal SGA children display an overall delay of linear craniofacial growth and a retrognathic mandible. High-dose GH treatment over 2 yrs leads to craniofacial catch-up growth, which is pronounced in regions where interstitial cartilage is involved and results in a less convex face in profile.