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Earn H Gan, Katie MacArthur, Anna L Mitchell, and Simon H S Pearce

Background

Autoimmune Addison's disease (AAD) is a rare condition with a complex genetic basis. A panel of rare and functionally defective genetic variants in the sialic acid acetylesterase (SIAE) gene has recently been implicated in several common autoimmune conditions. We performed a case–control study to determine whether these rare variants are associated with a rarer condition, AAD.

Method

We analysed nine SIAE gene variants (W48X, M89V, C196F, C226G, R230W, T312M, Y349C, F404S and R479C) in a United Kingdom cohort of 378 AAD subjects and 387 healthy controls. All samples were genotyped using Sequenom iPlex chemistry to characterise primer extension products.

Results

A heterozygous rare allele at codon 312 (312*M) was found in one AAD patient (0.13%) but was not detected in the healthy controls. The commoner, functionally recessive variant at codon 89 (89*V) was found to be homozygous in two AAD patients but was only found in the heterozygous state in controls. Taking into account all nine alleles examined, 4/378 (1.06%) AAD patients and 1/387 (0.25%) healthy controls carried the defective SIAE alleles, with a calculated odds ratio of 4.13 (95% CI 0.44–97.45, two-tailed P value 0.212, NS).

Conclusion

We demonstrated the presence of 89*V homozygotes and the 312*M rare allele in the AAD cohort, but overall, our analysis does not support a role for rare variants in SIAE in the pathogenesis of AAD. However, the relatively small collection of AAD patients limits the power to exclude a small effect.

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Marissa Penna-Martinez, Gesine Meyer, Anette Bøe Wolff, Beate Skinningsrud, Corrado Betterle, Alberto Falorni, William Er Ollier, Dag Undlien, Eystein Sverre Husebye, Simon H S Pearce, Anna L Mitchell, and Klaus Badenhoop

OBJECTIVE

While vitamin D regulates immune cells, little is known about it in autoimmune Addison´s disease (AAD). We investigated the vitamin D status in AAD patients from five European populations to assess its deficiency. In addition, we studied two case-control cohorts for vitamin D metabolism and pathway genes.

DESIGN

Cross-sectional study

METHODS

A total of 1028 patients with AAD from Germany (n=239), Italy (n=328), Norway (n=378), UK (n=44) and Poland (n=39) and 679 controls from Germany (n=301) and Norway (n=378) were studied for 25(OH)D3 (primary objective). Secondary objectives (1,25(OH)2D3 and pathway genes) were examined in case-controls from Germany and Norway correlating 25(OH)D3 and single nucleotide polymorphisms within genes encoding the vitamin D receptor (VDR), 1-α-hydroxylase (CYP27B1), 25-hydroxylase (CYP2R1); 24-hydroxylase (CYP24A1) and vitamin D binding protein (GC/DBP).

RESULTS

Vitamin D deficiency (25(OH)D3 10-20 ng/ml) was highly prevalent in AAD patients (34-57%), 5-22% were severely deficient (<10 ng/ml), 28-38% insufficient (20-30 ng/ml) and only 7-14% sufficient (>30 ng/ml). Lower 25(OH)D3 and 1,25(OH)2D3 levels were observed both in Norwegian and German AAD (p = 0.03/0.003 and p = 1 x 10-5/< 1 x 10-7, respectively) the former was associated with CYP2R1 (rs1553006) genotype G. Whereas controls achieved sufficient median 25(OH)D3 in summers (21.4 to 21.9 ng/ml), AAD patients remained largely deficient (18.0 to 21.2 ng/ml) and synthesize less 1,25(OH)2D3.

CONCLUSION

Vitamin D deficiency and insufficiency are highly prevalent in AAD patients. The vitamin D status of AAD may be influenced by genetic factors and suggests individual vitamin D requirements throughout the year.

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Claire L Wood, Kieren G Hollingsworth, Eric Hughes, Sadhanandham Punniyakodi, Robert Muni-Lofra, Anna Mayhew, Rod T Mitchell, Michela Guglieri, Timothy D Cheetham, and Volker Straub

Background

Pharmacological doses of glucocorticoids (GC) reduce inflammation and preserve muscle function in boys with Duchenne muscular dystrophy (DMD). Delayed puberty and bone fragility are consequences of GC treatment. The aim of this study was to determine the acceptability of a 2-year pubertal induction regimen using 4-weekly testosterone injections and examine changes in physique, bone integrity, muscle pathology (assessed by MRI) and muscle function.

Methods

Fifteen prepubertal males with DMD, aged 12–17 years and receiving GC, were treated with an incremental testosterone regimen for 2 years. Participants completed a Treatment Satisfaction Questionnaire (TSQM). Data on BMI, bone density, muscle pathology and function were collected at baseline and 2 years later.

Results

Testosterone injections were well tolerated, with high TSQM scores. Baseline BMI z-score was 2.16 (0.90) and 1.64 (1.35) 2 years later. Median testosterone levels were 9.7 nmol/L (IQR: 5.7–11.1) 6–9 months after the last injection with an associated increase in testicular volume. Lumbar spine z-score was 0.22 (s.d. 2.21) at baseline and 0.35 (s.d. 2.21) after 2 years. Upper and lower limb muscle contractile cross-sectional area increased in all participants during the trial (P = 0.05 and P < 0.01, respectively). There was a reduction in T2 relaxation times in most muscle groups with stable upper limb muscle function.

Conclusion

Incremental monthly testosterone injections were well tolerated, promoted endogenous testosterone production and had a positive impact on the skeleton and contractile muscle bulk with evidence suggesting a beneficial impact on the underlying disease process.