CAH-X syndrome is commonly found in CAH due to 21-hydroxylase deficiency and may result from various etiological mechanisms.

CSHI is a safe and well-tolerated modality of cortisol replacement that effectively approximates physiologic cortisol secretion in patients with classic CAH poorly controlled on conventional therapy. Improved adrenal steroid control and positive effects on HRQoL suggest that CSHI should be considered a treatment option for classic CAH. The long-term effect on established comorbidities requires further study.

Some variants that cause autosomal recessive congenital adrenal hyperplasia (CAH) also cause hypermobility type Ehlers-Danlos syndrome (EDS) due to the monoallelic presence of a chimera disrupting two flanking genes: CYP21A2, encoding 21-hydroxylase, necessary for cortisol and aldosterone biosynthesis, and TNXB, encoding tenascin-X, an extracellular matrix protein. Two types of CAH tenascin-X (CAH-X) chimeras have been described with a total deletion of CYP21A2 and characteristic TNXB variants. CAH-X CH-1 has a TNXB exon 35 120bp deletion resulting in haploinsufficiency and CAH-X CH-2 has a TNXB exon 40 c.12174C>G (p.Cys4058Trp) variant resulting in a dominant-negative effect. We present here three patients with biallelic CAH-X and identify a novel dominant-negative chimera termed CAH-X CH-3. Compared with monoallelic CAH-X, biallelic CAH-X results in a more severe phenotype with skin features characteristic of classical EDS. We present evidence for disrupted tenascin-X function and computational data linking the type of tenascin-X to disease severity.

Long-term use of CSHI is a safe and well-tolerated treatment option in a select set of adults with classic CAH. Improvements observed short term in disease control and subjective health status continued long term.

Management of adult patients with classic congenital adrenal hyperplasia (CAH) is challenging and often complicated by obesity, metabolic syndrome, and adverse cardiovascular risk. Alterations in weight can influence cortisol kinetics. A 19-year-old woman with classic CAH and morbid obesity experienced persistent elevations of androgen levels while receiving oral glucocorticoid therapy. Control of adrenal androgens was improved with continuous subcutaneous hydrocortisone infusion therapy, but obesity-related comorbidities persisted. After undergoing sleeve gastrectomy, the patient experienced dramatic weight loss, with improvement in insulin sensitivity and fatty liver in the postbariatric period. Cortisol clearance studies performed to evaluate changes in hydrocortisone dose requirements showed marked alternations in cortisol pharmacokinetics with decreases in volume of distribution and cortisol clearance, along with an increase in area under the curve for cortisol. Hydrocortisone dose was subsequently decreased 34% by 15 months after surgery. Effective control of androgen excess on this lower hydrocortisone dose was achieved and continues 27 months after surgery. This case highlights obesity-related complications of glucocorticoid replacement therapy in the management of CAH. Individual patient factors, such as fatty liver disease and insulin resistance, can have a clinically important effect on cortisol metabolism. Bariatric surgery was a safe and effective treatment of obesity in this patient with CAH and should be considered for patients with CAH and multiple obesity-related comorbidities.