Journal of Human Hypertension (2004) 18, 47–51 & 2004 Nature Publishing Group All rights reserved 0950-9240/04 $25.00 www.nature.com/jhh ORIGINAL ARTICLE Coexistence of different phenotypes in a family with glucocorticoid-remediable aldosteronism F Fallo1, C Pilon1, TA Williams2, N Sonino3, S Morra di Cella2, F Veglio2, R De Iasio4, P Montanari5 and P Mulatero2 1Department of Medical and Surgical Sciences, University of Padova, Italy; 2Department of Medicine and Experimental Oncology, University of Torino, Italy; 3Department of Statistical Sciences, University of Padova, Italy; 4CRBA, S Orsola Hospital, Bologna, Italy; 5City Hospital of Montecchio Emilia, Italy In glucocorticoid-remediable aldosteronism (GRA), activity. Sibling 1 was normotensive, normokalaemic there is a large interfamily variation of phenotype. We and had normal PRA and aldosterone. The father had report three subjects with GRA in a single family normal blood pressure and potassium, low-normal PRA (parents, two brothers and two sisters), of whom only and normal aldosterone. All three subjects had elevated one (proband) displayed classical features of the levels of urinary 18-hydroxycortisol and 18-oxocortisol. mineralocorticoid excess. The proband was a man Baseline 11-deoxycorticosterone (DOC), corticosterone found to be hypertensive and hypokalaemic at the age (B) and aldosterone were high in the proband and of 24 years. Plasma renin activity was suppressed and normal in the father and sibling 1; 11-deoxycortisol (S) plasma aldosterone was repeatedly elevated. Blood and cortisol (F) were normal. ACTH induced a normal pressure and aldosterone levels normalized within 5 increase of B, DOC, S and F, and an excessive days of dexamethasone therapy. The presence of a aldosterone increase in all three patients. Abnormalities chimaeric CYP11B1/CYP11B2 gene was demonstrated in the chimaeric portions of CYB11B1 or CYP11B2 genes by long-PCR and Southern blotting (crossover site at the did not account for the phenotypic disparity of the end of intron 3) in the proband, in the younger sister different members in a single GRA family. Altered (sibling 1) and in the father. In these patients, sequen- regulation of the chimaeric gene may be responsible cing of the chimaeric portion of CYP11B1 did not reveal for differences in its activity. any mutation, while sequencing of the chimaeric portion Journal of Human Hypertension (2004) 18, 47–51. of CYP11B2 showed a V386A polymorphism in exon 7, doi:10.1038/sj.jhh.1001636 known to cause only a minimal impairment of enzymatic Keywords: genotype; phenotype; glucocorticoid-remediable aldosteronism Introduction coid therapy.2,3 The genetic abnormality results from the inheritance of a hybrid gene derived from the Glucocorticoid-remediable aldosteronism (GRA) is a crossover between the 50-regulatory ACTH-respon- rare autosomal dominant disorder of adrenocortical sive sequence of the CYP11B1 (11b-hydroxylase) steroid synthesis, in which aldosterone secretion is gene and the 30-coding region of the CYP11B2 solely regulated by adrenocorticotropin (ACTH) 4 1 (aldosterone synthase) gene, and can be detected rather than angiotensin II. In the classical form, by a reliable and simple long-PCR test.5 A consider- this syndrome is characterized by hypokalaemia, able interfamily variation has been described for hyperaldosteronism and suppressed plasma renin many GRA phenotypic traits, including blood activity (PRA), presents at a young age in association pressure, aldosterone and PRA levels, hypokalaemia with familial occurrence of hypertension and cere- and occurrence of cerebrovascular accidents,2,3 and bral haemorrhage, and is correctable by glucocorti- no relationship between genotype and phenotype has been found.6,7 Scarce data are available on the intrafamily variation of phenotype in patients with Correspondence: Dr F Fallo, Department of Medical and Surgical genetically proved GRA. While in the family Sciences, University of Padova, Via Ospedale 105, 35128 Padova, previously reported by us8 and in that described Italy. 9 E-mail: [email protected] by Rich et al, the penetrance of hypertension and Received 12 May 2003; revised 5 August 2003; accepted 7 August aldosteronism was high in all affected pedigree 2003 members, in the family of Gates et al10 and in Different phenotypes in GRA F Fallo et al 48 another one more recently reported by us,11 the great 11-deoxycortisol (S) and cortisol (F) were normal. majority of affected members had mild hypertension ACTH administration induced a normal increase of and normal biochemistry, including serum potas- B, DOC, S and F, and an excessive increase of sium. Here we report a new family of six members in aldosterone. After 4 days of dexamethasone treat- which three subjects have been identified as ment (0.5 mg every 6 h) blood pressure decreased, possessing the same type of CYP11B1/CYP11B2 aldosterone fell to undetectable levels and serum chimaeric fusion, but display diverse biochemical potassium increased slightly. On a long-term basis, and clinical phenotypes. dexamethasone 0.250 mg/day in combination with nifedipine 10 mg t.i.d. controlled blood pressure and serum potassium levels. The presence of the Case reports chimaeric CYP11B1/CYP11B2 gene was demon- strated by long PCR and Southern blotting of The Proband genomic DNA. Sequencing of the chimaeric PCR product demonstrated that the crossover site was A 34-year-old man was referred to our centre for located at the end of intron 3, just before the evaluation of refractory hypertension. He had been beginning of exon 4. initially diagnosed with hypertension and hypo- kalaemia at 24 years of age. Primary aldosteronism was suspected on the basis of low PRA and elevated Family screening plasma and urinary aldosterone after repeated measurements. Abdominal CT scan and 75Se- All living first-degree family members were ana- methyl-nor-cholesterol adrenal scintiscan were in- lysed. The clinical, biochemical and genetic data are terpreted as showing adrenal bilateral hyperplasia, reported in Table 1. Body mass index (BMI) and and adrenal venous catheterization revealed sym- waist circumference were in the normal range for all metric, elevated secretion of aldosterone. The members, except the affected father and the un- patient had poorly controlled blood pressure for affected mother, who both showed mild overweight. many years while on multiple medical regimen, Blood pressure measurements and baseline data including spironolactone, calcium-channel blockers were obtained in the two parents and the three and ACE inhibitors. He was evaluated as an out- siblings (one brother and two sisters), evaluated as patient on an unrestricted sodium and potassium outpatients on an unrestricted sodium and potas- diet, and 3 weeks after withdrawal of antihyperten- sium diet. All siblings and the two parents were sive medications. There was no family history of found to be normotensive and normokalaemic, and hypertension or of early death from cerebrovascular had normal plasma and urinary aldosterone. The events. The proband’s blood pressure was 210/ father had low-normal PRA. No clinical conditions 110 mmHg, his serum potassium was 2.5 mmol/l, that could lower blood pressure, that is heart failure, upright PRA was suppressed and plasma and were present in the father. The father and the urinary aldosterone levels were elevated (Table 1). younger sister (ie, sibling 1) had high urinary 18- Routine biochemistry and renal scintigraphy were OHF and 18-oxoF. In these two subjects, an ACTH- normal. The EKG showed left ventricular hypertro- stimulation test was performed, following the same phy. Urinary levels of 18-hydroxycortisol (18-OHF) protocol described above. While baseline and and 18-oxocortisol (18-oxoF) were elevated. On a ACTH-stimulated plasma DOC, B, S and F were different day, ACTH 1-24 250 mg (Synacthen, Novar- normal, aldosterone was hyper-responsive to ACTH, tis Pharma) was injected as an i.v. bolus at 10.00 h as in the proband (Table 2). Sibling 1 and the father into the subject after a 30-min rest in a seated showed the same gene abnormality and the same position. Baseline 11-deoxycorticosterone (DOC), chimaeric gene crossover point of the proband. The corticosterone (B) and aldosterone were high, and crossover site was in the same region found in Table 1 Clinical, biochemical and genetic data of the family members Normal values Proband Sibling 1 Father Sibling 2 Sibling 3 Mother Age (years)/sex (M/F) 34/M 21/F 65/M 36/F 29/M 61/F BMI (kg/m2) o25 22 19 27 22 24 24 Waist circumference (cm) o102 Mo88 F 82 67 99 79 86 84 CYP11B1/CYP11B2 chimaeric gene Positive Positive Positive Negative Negative Negative Blood pressure (mmHg) o140/o90 210/110 125/80 140/80 120/85 120/70 135/85 Serum K (mmol/l) 3.5–5.0 2.5 4.3 4.0 4.4 4.4 4.2 Upr. PRA (ng/ml.h) 1.3–5.2 0.1 2.6 1.0 4.8 3.9 3.5 Upr. Aldosterone (pmol/l) 140–830 1166 510 338 624 680 416 Urinary aldosterone (nmol/day) 8–83 138.1 48.8 40.8 50.2 42.8 32.9 Urinary 18-OHF (mmol/day) 0.05–0.29 6.61 1.83 5.81 0.15 0.24 0.29 Urinary 18-oxoF (nmol/day) 0.5–3.9 234.0 42.5 161.7 2.9 2.1 3.2 Journal of Human Hypertension Different phenotypes in GRA F Fallo et al 49 Table 2 Plasma steroid levels in the three patients with GRA and normal controls before and after ACTH administration DOC (pmol/l) B (pmol/l) ALDO (pmol/l) S (nmol/l) F (nmol/l) Proband Baseline 966 11 268 747 0.96 310 ACTH 2719 88 876 2916 3.64 625 Sibling 1 Baseline 466 3112 238 1.05 376 ACTH 1933 49 835 1105 4.51 774 Father Baseline 370 3910 397 0.57 292 ACTH 1537 47 291 2391 2.88 727 Normal subjects (n=10)a Baseline 449 7 88 4148 7 1155 318 7 117 0.82 7 0.35 358 7 116 ACTH 1330 7 508 62 058 7 9866 735 7 314 4.10 7 1.33 877 7 174 DOC, 11-deoxycorticosterone; B, corticosterone; ALDO, aldosterone; S, 11-deoxycortisol; F, cortisol.