Monogenic Hypertension in Children: A Review With Emphasis on Genetics

Hypertension in Children and Young Adults

Primary hypertension (PH) is most common during adolescence with increasing prevalence globally, alongside the epidemic of obesity. Unlike in adults, there are no data on children with uncontrolled hypertension and their future risk of hard cardiovascular and cerebrovascular outcomes. However, hypertension in childhood is linked to hypertensive-mediated organ damage (HMOD) which is often reversible if treated appropriately. Despite differing guidelines regarding the threshold for defining hypertension, there is consensus that early recognition and prompt management with lifestyle modification escalating to antihypertensive medication is required to ameliorate adverse outcomes. Unfortunately, many unknowns remain regarding pathophysiology and optimum treatment of childhood hypertension.

Pediatric Liddle Syndrome Caused by a Novel SCNN1G Variant in a Chinese Family and Characterized by Early-Onset Hypertension

BACKGROUND

Liddle syndrome (LS), an autosomal dominant disorder, is a common monogenic hypertension in pediatrics. In this study, we reported a novel SCNN1G variant in a Chinese family with pediatric LS, and conduct a systematic review of epithelial sodium channel (ENaC)-gene-positive LS cases to conclude the clinical genetic features of LS in childhood.

METHODS

Next-generation sequencing and in silico analysis were performed in the proband to discover candidate variants. Sanger sequencing was used to identify the predicted likely pathogenic variant. LS patients in this family were treated with amiloride. The Medline database was searched to summarize clinical features of pediatric LS cases whose age at genetic diagnosis was not more than 18 years.

RESULTS

Genetic analysis identified a novel SCNN1G missense variant (c.1874C>T, p.Pro625Leu) in the proband with LS in childhood. In silico analysis revealed this heterozygous variant was highly conserved and deleterious. A total of 38 publications described pediatric LS associated with 25 pathogenic variants in SCNN1B and SCNN1G in 54 children. Despite the phenotypic heterogeneity, early-onset hypertension is the most common feature. All LS patients in this family or the reviewed cases showed significantly improvements in hypertension and hypokalemia after treatment with ENaC inhibitors.

CONCLUSIONS

This study identified a novel SCNN1G missense variant in a patient with pediatric LS, expanding the genetic spectrum of SCNN1G and demonstrating the PY motif of γ-ENaC as a potential mutant region. Early identification and specific management of LS in children and adolescents are important to prevent the development of hypertensive end-organ disease.

Monogenic hypertension

Hypertension is a significant public health problem. Thirty percent of cases are caused by a single genetic mutation. Hypertension is the predominant and usually the only manifestation in monogenic hypertension Monogenic hypertension may involve mineralcorticoid-dependent or -independent increase in Na⁺ transport. Diagnosis is based on routine physical examination, blood pressure measurement and laboratory analysis of renin, aldosterone, cortisol and potassium. Genetic testing is useful for confirming diagnosis and for differential diagnosis. Monogenic hypertension has autosomal dominant or autosomal recessive inheritance. (www.actabiomedica.it)

Pediatric Hypertension: Diagnosis, Evaluation, and Treatment

The etiology of hypertension in children and adolescents is varied; however, the prevalence of pediatric primary hypertension is increasing. Early identification and appropriate management of hypertension in children and adolescents is important to prevent the development of hypertensive end organ disease. The 2017 American Academy of Pediatrics Clinical Practice Guidelines for the Screening and Management of High Blood Pressure in Children and Adolescents provide a comprehensive reference for evaluation and management of hypertension in this age group and should be used when assessing patients with elevated blood pressure and hypertension.

Overview of Monogenic or Mendelian Forms of Hypertension

Monogenic or Mendelian forms of hypertension are described as a group of conditions characterized by insults to the normal regulation of blood pressure by the kidney and adrenal gland. These alterations stem from single mutations that lead to maladaptive overabsorption of electrolytes with fluid shift into the vasculature, and consequent hypertension. Knowledge of these various conditions is essential in diagnosing pediatric or early-onset adult hypertension as they directly affect treatment strategies. Precise diagnosis with specific treatment regimens aimed at the underlying physiologic derangement can restore normotension and prevent the severe sequelae of chronic hypertension.