Congenital hyperreninemic hypoaldosteronism due to aldosterone synthase deficiency type I in a Portuguese patient - Case report and review of literature

SUMMARY Hyperreninemic hypoaldosteronism due to aldosterone synthase (AS) deficiency is a rare condition typically presenting as salt-wasting syndrome in the neonatal period. A one-month-old Portuguese boy born to non-consanguineous parents was examined for feeding difficulties and poor weight gain. A laboratory workup revealed severe hyponatremia, hyperkaliaemia and high plasma renin with unappropriated normal plasma aldosterone levels, raising the suspicion of AS deficiency. Genetic analysis showed double homozygous of two different mutations in the CYP11B2 gene: p.Glu198Asp in exon 3 and p.Val386Ala in exon 7. The patient maintains regular follow-up visits in endocrinology clinics and has demonstrated a favourable clinical and laboratory response to mineralocorticoid therapy. To our knowledge, this is the first Portuguese case of AS deficiency reported with confirmed genetic analysis.

Congenital hypoaldosteronism.

Congenital hypoaldosteronism due to an isolated aldosterone biosynthesis defect is rare. We report a 4 month old female infant who presented with failure to thrive, persistent hyponatremia and hyperkalemia. Investigations revealed normal serum 17 hydroxy progesterone and cortisol. A decreased serum aldosterone and serum 18 hydroxy corticosterone levels with a low 18 hydroxy corticosterone: aldosterone ratio was suggestive of corticosterone methyl oxidase type I deficiency. She was started on fludrocortisone replacement therapy with a subsequent normalization of electrolytes. Further molecular analysis is needed to ascertain the precise nature of the mutation.