Growth patterns and outcomes of growth hormone therapy in patients with acrodysostosis

INTRODUCTION

Severe short stature is a feature of acrodysostosis, but data on growth are sparse. Treatment with recombinant human growth hormone (rhGH) is used in some centers to increase final height, but no studies have been published so far. Our objective was to conduct a multicenter, retrospective, cohort study to investigate growth in individuals with both types of acrodysostosis, treated with rhGH or not; we used the new nomenclature to describe acrodysostosis, as this disease belongs to the large group of inactivating PTH/PTHrP signaling disorders (iPPSD); acrodysostosis refers to iPPSD4 (acrodysostosis type 1 due to PRKAR1A mutations) and iPPSD5 (acrodysostosis type 2, due to PDE4D mutations).

METHODS

We present auxological data from individuals with genetically characterized iPPSD4, and participants with clinical features of iPPSD5.

RESULTS

We included 20 and 17 individuals with iPPSD4 and iPPSD5, respectively. The rhGH-treated iPPSD4 patients (n = 9) were smaller at birth than those who did not receive rhGH (median - 2.2 SDS vs. - 1.7 SDS); they showed a trend to catch-up growth during rhGH therapy (median 0.5 SDS in the first year). The rhGH-treated patients (n = 5) reached a better final height compared to those who did not receive rhGH (n = 4) (median - 2.8 SDS vs. - 3.9 SDS), suggesting that rhGH is efficient to increase height in those patients. The difference in target height to final height ranged between 1.6 and 3.0 SDS for iPPSD4 not treated with rhGH (n = 4), 2.1-2.8 SDS for rhGH-treated iPPSD4 (n = 5), 0.6-5.5 SDS for iPPSD5 not treated with rhGH (n = 5) and 2.5-3.1 for rhGH-treated iPPSD5 (n = 2).

CONCLUSION

Final height may be positively influenced by rhGH in patients with acrodysostosis/iPPSD. Our rhGH-treated cohort started therapy relatively late, which might explain, at least in part, the limited effect of rhGH on height.

Craniosynostosis and metabolic bone disorder. A review

INTRODUCTION

Some metabolic bone disorders may result in the premature closure of one or more calvarial sutures during childhood, potentially leading to a cranioencephalic disproportion. The aim of this paper is to review the characteristics and consequences of craniosynostosis associated with metabolic disorder.

MATERIAL AND METHODS

A review of the literature on metabolic forms of craniosynostosis was performed.

RESULTS

The most common forms of craniosynostosis associated with metabolic bone disorder were isolated sagittal suture fusion with or without scaphocephaly, and sagittal suture fusion associated with coronal suture fusion (oxycephaly) or also with lambdoid suture fusion (pansynostosis). Synostosis may be well-tolerated, but in some subjects results in neurodevelopmental and functional impairment that is sometimes severe.

CONCLUSION

The impact of metabolic synostosis is very variable, depending on the specific underlying metabolic disease, with a large spectrum of morphological and functional consequences. Diagnosis should be early and management should be carried out by a multidisciplinary team with expertise in both rare skeletal disorders and craniosynostosis. The impact of emergent medical therapies recently developed for some of these diseases will be assessed by systematic coherent follow-up of international registries.

Outcomes of orthopedic surgery in a cohort of 49 patients with X-linked hypophosphatemic rickets (XLHR)

BACKGROUND

X-linked hypophosphatemic rickets (XLHR) is due to mutations in PHEX leading to unregulated production of FGF23 and hypophosphatemia. XLHR is characterized by leg bowing of variable severity. Phosphate supplements and oral vitamin analogs, partially or, in some cases, fully restore the limb straightness. Surgery is the alternative for severe or residual limb deformities.

OBJECTIVE

To retrospectively assess the results of surgical limb correction in XLHR (osteotomies and bone alignment except for 3 transient hemiepiphysiodesis).

METHODS

We analyzed the incidence of recurrence and post-surgical complications in 49 XLHR patients (29F, 20M) (mean age at diagnosis 6.0 years (± 7.1)).

RESULTS

At first surgery, the mean age was 13.4 years (± 5.0). Recurrence was observed in 14/49 (29%) patients. The number of additional operations significantly decreased with age (2.0 (± 0.9), 1.7 (± 1.0) and 1.2 (± 0.4) in children <11 years, between 11 and 15, and >15 years; P < 0.001). Incidence of recurrence seemed to be lower in patients with good metabolic control of the rickets (25% vs 33%). Complications were observed in 57% of patients.

CONCLUSION

We report a large series of surgical procedures in XLHR. Our results confirm that phosphate supplements and vitamin D analog therapy is the first line of treatment to correct leg bowing. Surgery before puberty is associated with a high risk of recurrence of the limb deformity. Such procedures should only be recommended, following multidisciplinary discussions, in patients with severe distortion leading to mechanical joint and ligament complications, or for residual deformities once growth plates have fused.

Phosphate and Vitamin D Prevent Periodontitis in X-Linked Hypophosphatemia

X-linked hypophosphatemia (XLH) is a rare genetic skeletal disease where increased phosphate wasting in the kidney leads to hypophosphatemia and prevents normal mineralization of bone and dentin. Here, we examined the periodontal status of 34 adults with XLH and separated them according to the treatment they received for hypophosphatemia. We observed that periodontitis frequency and severity were increased in adults with XLH and that the severity varied according to the hypophosphatemia treatment. Patients who benefited from an early and continuous vitamin D and phosphate supplementation during their childhood presented less periodontal attachment loss than patients with late or incomplete supplementation. Continued hypophosphatemia treatment during adulthood further improved the periodontal health. Extracted teeth from patients with late or incomplete supplementation showed a strong acellular cementum hypoplasia when compared with age-matched healthy controls. These results show that XLH disturbs not only bone and dentin formation but also cementum and that the constitutional defect of the attachment apparatus is associated with attachment loss.

Decrease in clinical hypoglycemia in young children with type 1 diabetes treated with free-mixed aspart and detemir insulin: an open labeled randomized trial

OBJECTIVE

To compare the effectiveness of a free-mix of aspart (A) and detemir (D) insulins (ADIM) with a commonly used premixed fixed-ratio aspart and neutral protamine Hagedorn (NPH) insulin mixture (ANIM) in young children with type 1 diabetes (T1D) treated with twice-daily injections. The trial thus compares not only D vs. NPH, but also flexible, personalized insulin preparations vs. a fixed premixed preparation.

RESEARCH DESIGN AND METHODS

This single-center, open-label, randomized trial included 82 children with T1D. Patients stayed on ANIM for 1 yr of optimization of disease management, then were randomized to either ANIM (N = 41) or ADIM (N = 41) for another year.

OUTCOMES

Frequency of severe or symptomatic episodes, glycated hemoglobin A1c (HbA1c), and blood glucose (BG) values.

RESULTS

Compared with ANIM, ADIM decreases symptomatic hypoglycemia by approximately 2 fold (p < 0.001) and severe hypoglycemia by 7-10 fold (p = 0.04). ADIM somewhat reduced BG variation. Mean HbA1c was comparable on ADIM (7.9 ± 0.8 %; 63 ± 9 mmol/mol) and ANIM (8.2 ± 0.7 %; 66 ± 8 mmol/mol).

CONCLUSIONS

Using a free-mixing preparation of aspart and detemir insulin decreases hypoglycemia in young children with type 1 diabetes.

Effects of a controlled hypoglycaemia test on QTc in adolescents with Type 1 diabetes

Our objective was to test the ventricular repolarization response to a controlled hypoglycaemia test in Type 1 diabetic adolescents, an age group at risk for 'dead in bed syndrome'. We measured QTc, blood glucose level, potassium, heart rate, blood pressure and urinary metanephrine levels in 16 Type 1 diabetic adolescents during an insulin clamp mimicking the transition from mild hyperglycaemia to hypoglycaemia. QTc increased in all patients by 146 +/- 44 ms (mean +/-sd) ranging from 70 to 230 ms. The longest QTc (630 ms) was recorded in the sibling of a diabetic patient found 'dead in bed'. Heart rate and urinary metanephrine levels correlated with QTc (r = 0.60 and 0.79, respectively; P = 0.02 and 0.003). QTc in euglycaemia showed no correlation with hypoglycaemia associated QTc prolongation. The prognostic value of the hypoglycaemia test for the risk of recurrent episodes of QTc prolongation should be evaluated in real-life conditions in large-scale studies of diabetic adolescents.