[Update on endocrine hypertension]

[Etiology of endocrine arterial hypertensions: about a series of cases]

Arterial hypertensions (HTA) of endocrine origin are a rare cause of hypertension; HTA overall prevalence don't exceed 4% of hypertensive patients. Research interest in endocrine HTA is due to the severity of some life-threatening, potentially curable and reversible forms of HTA. The aim of our study was to determine the clinical, paraclinical, etiological and therapeutic profile of secondary HTA of endocrine origin in patients treated in endocrinology department at the University Hospital Mohamed VI in Marrakech. We conducted a prospective, descriptive study spanned 4 years, enrolling 45 patients with endocrine HTA. The average age was 44.89 years, with a clear predominance of women (sex ratio 0.49). Etiology of endocrine HTA was dominated by pheochromocytoma (17 cases), hypercorticism (11 cases) and acromegaly (8 cases). HTA were paroxysmal in 24.4%. HTA were immediately classified as grade 3 severe in 40% of cases. HTA were complicated by heart disease in 24% of cases and by renal disease in 20% of cases. Curative treatment cleared up HTA in 60% of cases (27 cases). The diagnosis of secondary endocrine HTA is sometimes difficult because of the lack of clinical specificity. It is not unusual for HTA to be the only manifestation of the disease. In our study we noted the paroxysmal and severe nature of HTA. The potentially curable nature of HTA in more than two thirds of cases, demostrates the importance of early diagnosis of each severe HTA resistant to treatment or in the presence of suggestive clinical, biological or radiological signs.

Overview of the genetic determinants of primary aldosteronism

Primary aldosteronism is the most common cause of secondary hypertension. The syndrome accounts for 10% of all cases of hypertension and is primarily caused by bilateral adrenal hyperplasia or aldosterone-producing adenoma. Over the last few years, the use of exome sequencing has significantly improved our understanding of this syndrome. Somatic mutations in the KCNJ5, ATP1A1, ATP2B3 or CACNA1D genes are present in more than half of all cases of aldosterone-producing adenoma (~40%, ~6%, ~1% and ~8%, respectively). Germline gain-of-function mutations in KCNJ5 are now known to cause familial hyperaldosteronism type III, and an additional form of genetic hyperaldosteronism has been reported in patients with germline mutations in CACNA1D. These genes code for channels that control ion homeostasis across the plasma membrane of zona glomerulosa cells. Moreover, all these mutations modulate the same pathway, in which elevated intracellular calcium levels lead to aldosterone hyperproduction and (in some cases) adrenal cell proliferation. From a clinical standpoint, the discovery of these mutations has potential implications for patient management. The mutated channels could be targeted by drugs, in order to control hormonal and overgrowth-related manifestations. Furthermore, some of these mutations are associated with high cell turnover and may be amenable to diagnosis via the sequencing of cell-free (circulating) DNA. However, genotype-phenotype correlations in patients harboring these mutations have yet to be characterized. Despite this recent progress, much remains to be done to elucidate the yet unknown mechanisms underlying sporadic bilateral adrenal hyperplasia.