BackgroundAldosterone synthase (CYP11B2) deficiency is a rare autosomal recessive disorder, usually presenting with severe salt-wasting in infancy or stress-induced hyperkalaemia and postural hypotension in adulthood. Neonatal screening for congenital adrenal hyperplasia, another cause of salt wasting, using 17-hydroxyprogesterone measurement would fail to detect aldosterone synthase deficiency, a diagnosis which may be missed until the patient presents with salt-wasting crisis. Due to this potential life-threatening risk, comprehensive hormonal investigation followed by genetic confirmation for suspected patients would facilitate clinical management of the patient and assessment of the genetic implication in their offspring.Case presentationWe describe a 33-year old Chinese man who presented in infancy with life-threatening hyponatraemia and failure to thrive, but remained asymptomatic on fludrocortisone since. Chromosomal analysis confirmed a normal male karyotype of 46, XY. Plasma steroid profile showed high plasma renin activity, low aldosterone level, and elevated 18-hydroxycorticosterone, compatible with type 2 aldosterone synthase deficiency. The patient was heterozygous for a novel CYP11B2 mutation: c.977C > A (p.Thr326Lys) in exon 3. He also carried a heterozygous mutation c.523_525delAAG (p.Lys175del) in exon 6, a known pathogenic mutation causing aldosterone synthase deficiency. Sequencing of CYP11B2 in his parents demonstrated that the mother was heterozygous for c.977C > A, and the father was heterozygous for c.523_525delAAG.ConclusionAlthough a rare cause of hyperreninaemic hypoaldosteronism, aldosterone synthase deficiency should be suspected and the diagnosis sought in patients who present with life-threatening salt-wasting in infancy, as it has a good long-term prognosis when adequate fludrocortisone replacement is instituted. To our knowledge, this is the first Chinese patient in which the molecular basis of aldosterone synthase deficiency has been identified.

OBJECTIVEWe conducted a retrospective cohort study assessing the prevalence and clinical and radiological outcome of remote areas of bone marrow edema on magnetic resonance imaging (MRI) in the feet of subjects with diabetes and neuropathic foot ulceration.RESEARCH DESIGN AND METHODSMRIs performed over 6 years looking for osteomyelitis associated with neuropathic lesions were assessed for remote areas of signal change.RESULTSSeventy MRI studies were assessed. Remote areas of signal change were present in 21 (30%) subjects, involved midfoot or hindfoot in 20 subjects, were associated with younger age and renal replacement therapy, and did not predict future Charcot neuroarthropathy or infection at that site. Repeat MRIs in 11 subjects with such areas found that none had progressed, six had improved, and two had resolved; in 29 subjects without such areas, five had developed new areas.CONCLUSIONSBone marrow edema in the midfoot and hindfoot of subjects with diabetes and neuropathic lesions is common, often transient, and of unknown significance.