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.

[Incidence of type 1 diabetes in Navarre (2009-2016): higher in the southern regions of the autonomous community]

BACKGROUND

Geographical and seasonal variations of type 1 diabetes (T1D) are useful for establishing the key ethio-pathogenic factors of the disease. The present work seeks to analyze the incidence rates of T1D in Navarre for the 2009-2016 period, its geographical distribution and seasonal variations in birth and diagnosis in affected persons.

METHODS

Prospective study with one primary and three secondary sources. The completeness of the registry, determined using the capture-recapture method, was 96.08%. The confidence intervals of zone and onset season incidence rates were determined assuming an underlying Poisson distribution. Adjusted effect of onset age, sex, onset season and geographical area over changes in incidence rates were analyzed using a Poisson regression model. Comparison among areas was carried out after the corresponding adjustments of incidence by the indirect standardization method.

RESULTS

Four hundred and twenty-eight new cases were detected (incidence= 8.36/100,000 inhabitants per year, CI95%: 7.58-9.19). The disease is predominant in males (63% of patients). The incidence in children under 15 years was higher than in adults (21.54, CI95%: 18.43-25.02 vs. 5.94, CI95%: 5.23-6.71; p<0.001). Incidence was highest in the four southern regions of Navarre, most of the cases being in winter and spring. No differences were found regarding birth season over incidence.

CONCLUSION

Navarre maintains a high T1D incidence in childhood that decreases progressively with age. Sex, age group, geographical zone and onset season are independently associated with the incidence rates observed in the study.

PRKAR1A and PDE4D mutations cause acrodysostosis but two distinct syndromes with or without GPCR-signaling hormone resistance

CONTEXT

Acrodysostosis is a rare skeletal dysplasia that is associated with multiple resistance to G protein-coupled receptor (GPCR) signaling hormones in a subset of patients. Acrodysostosis is genetically heterogeneous because it results from heterozygous mutations in PRKAR1A or PDE4D, two key actors in the GPCR-cAMP-protein kinase A pathway.

OBJECTIVE

Our objective was to identify the phenotypic features that distinguish the two genotypes causing acrodysostosis.

PATIENTS AND METHODS

Sixteen unrelated patients with acrodysostosis underwent a candidate-gene approach and were investigated for phenotypic features.

RESULTS

All patients had heterozygous de novo mutations. Fourteen patients carried a PRKAR1A mutation (PRKAR1A patients), five each a novel PRKAR1A mutation (p.Q285R, p.G289E, p.A328V, p.R335L, or p.Q372X), nine the reported PRKAR1A p.R368X mutation; two patients harbored a mutation in PDE4D (PDE4D patients) (one novel mutation, p.A227S; one reported, p.E590A). All PRKAR1A, but none of the PDE4D mutated patients were resistant to PTH and TSH. Two PRKAR1A patients each with a novel mutation presented a specific pattern of brachydactyly. One PDE4D patient presented with acroskyphodysplasia. Additional phenotypic differences included mental retardation in PDE4D patients. In addition, we report the presence of pigmented skin lesions in PRKAR1A and PDE4D patients, a feature not yet described in the acrodysostosis entity.

CONCLUSIONS

All PRKAR1A and PDE4D patients present similar bone dysplasia characterizing acrodysostosis. Phenotypic differences, including the presence of resistance to GPCR-cAMP signaling hormones in PRKAR1A but not PDE4D patients, indicate phenotype-genotype correlations and highlight the specific contributions of PRKAR1A and PDE4D in cAMP signaling in different tissues.

[Low height and rare diseases]

Low stature is the main reason of consultation in paediatric endocrinology. In a high percentage of cases, its etiology is clear and fundamentally answers to variants of normality. However, in approximately 20% of cases low stature is pathological and requires exhaustive studies. The association of rare diseases (RD) with low height is very frequent. In this article we review the etiology of low height, describing: - The genetic forms of the growth hormone (GH), whether isolated or associated with malformations of the average line or others. - Those which are of great importance due to their clinical repercussion, such as Turner's Syndrome, Noonan's Syndrome and Willi-Prader's Syndrome. - The frequent osseous dysplasias, in some cases with genetic alterations of the SHOX gene, situated in the short arm of the Xp chromosome. The importance of these diagnoses lies in the possibility of carrying out early and efficient treatment, in some of them, with GH. In conclusion, the diagnosis of rare diseases with low height is a current and normal challenge in paediatric endocrinology due to the great advances in molecular genetics and the possibility of treatment in some of them. It always involves a multidisciplinary approach due to the frequent association of pathology it presents, and, in its turn, it offers the possibility of carrying out timely genetic counselling.

[Familial benign partial epilepsy of early infancy]

INTRODUCTION AND CLINICAL CASES

We present two patients who at the ages of 5 and 17 months respectively presented with convulsive crises with motor signs, of partial onset and secondary generalization, which eventually became normal. Both patients had a family history of first degree relatives with similar illnesses and are at present-five years later-well and with normal development, school achievement and neurological examination findings. The clinical characteristics, normal biochemical and neuroimaging investigations and EEG characteristics suggest the diagnosis of benign partial epilepsy of early infancy. This syndrome is characterized by its appearance during the first year of life, having no known etiological factors, with partial crises occurring several times a day and with a course leading to remission. Its frequency may be greater than is thought. There is a pattern of dominant autosomal inheritance, with a gene recently found on chromosome 19.

CONCLUSION

We consider that this syndrome should be included in the International Classification of Epilepsy and Epileptic Syndromes as benign familial idiopathic partial epilepsy.

[Andermann syndrome: presentation of a case]

INTRODUCTION

Peripheral neuropathy with agenesis of the corpus callosum (or Andermann's syndrome) is a hereditary autosomal recessive disorder rarely found outside certain regions of Quebec Province (Canada). It is associated with mental retardation and various dysmorphic changes. Deterioration is usually progressive with loss of motor skills, development of scoliosis during adolescence, tendency to behaviour disorders and death during the third decade (approximately).

CLINICAL CASE

We present a 13 year old girl diagnosed as having the spastic tetraparesic type of PCI, who was sent to us so that we could reconsider the diagnosis in view of the atypical course of the illness. The patient had an unusual phenotype with dysmorphic changes (mainly facial), axial hypotonia with flexion-retraction of the hands, generalized arreflexia, neurogenic bladder, skin changes with ulcers on the legs and mental retardation. Neurophysiological studies showed a predominantly motor polyneuropathy. There were signs of axonal neuropathy on both sural nerve and skeletal muscle biopsies. The clinical features, phenotype, microcephaly with agenesis of the corpus callosum and a posterior fossa cyst, associated with spinal atrophy indicated the diagnosis of Andermann's syndrome.

CONCLUSIONS

This case is of interest in view of the exceptional rarity of Andermann's syndrome in our population.