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Neuronal migration defects, including pachygyria, are among the most severe developmental brain defects in humans. Here, we identify biallelic truncating mutations in CTNNA2, encoding αN-catenin, in patients with a distinct recessive form of pachygyria. CTNNA2 was expressed in human cerebral cortex, and its loss in neurons led to defects in neurite stability and migration. The αN-catenin paralog, αE-catenin, acts as a switch regulating the balance between β-catenin and Arp2/3 actin filament activities. Loss of αN-catenin did not affect β-catenin signaling, but recombinant αN-catenin interacted with purified actin and repressed ARP2/3 actin-branching activity. The actin-binding domain of αN-catenin or ARP2/3 inhibitors rescued the neuronal phenotype associated with CTNNA2 loss, suggesting ARP2/3 de-repression as a potential disease mechanism. Our findings identify CTNNA2 as the first catenin family member with biallelic mutations in humans, causing a new pachygyria syndrome linked to actin regulation, and uncover a key factor involved in ARP2/3 repression in neurons.

Increasing evidence indicates that inflammation plays a role in PTSD and stress disorder pathophysiology. PTSD is consistently associated with higher circulating inflammatory protein levels. Rodent models demonstrate that inflammation promotes enduring avoidance and arousal behaviors after severe stressors (e.g., predator exposure and social defeat), suggesting that inflammation may play a mechanistic role in trauma disorders. C-reactive protein (CRP) is an innate acute phase reactant produced by the liver after acute infection and chronic disease. A growing number of investigations report associations with PTSD diagnosis and elevated peripheral CRP, CRP gene mutations, and CRP gene expression changes in immune signaling pathways. CRP is reasonably established as a potential marker of PTSD and trauma exposure, but if and how it may play a mechanistic role is unclear. In this review, we discuss the current understanding of immune mechanisms in PTSD with a particular focus on the innate immune signaling factor, CRP. We found that although there is consistent evidence of an association of CRP with PTSD symptoms and risk, there is a paucity of data on how CRP might contribute to CNS inflammation in PTSD, and consequently, PTSD symptoms. We discuss potential mechanisms through which CRP could modulate enduring peripheral and CNS stress responses, along with future areas of investigation probing the role of CRP and other innate immune signaling factors in modulating trauma responses. Overall, we found that CRP likely contributes to central inflammation, but how it does so is an area for further study.

We previously reported on the lack of utility of the 1 mg overnight dexamethasone (DEX) test in mild and/or periodic Cushing's syndrome, as most patients with the condition suppressed to 1 mg DEX. It is possible that a lower dose of DEX as part of an overnight DEX test might be able to distinguish between mild and/or periodic Cushing's syndrome and those without the condition. The objective of the current study is to determine the sensitivity and specificity of a 0.25 mg overnight DEX suppression test, the standard 1 mg overnight DEX suppression test, and the two-day low-dose (Liddle test) DEX suppression test with and without correction for DEX levels in patients evaluated for mild and/or periodic Cushing's syndrome. Thirty patients determined to have Cushing's syndrome by biochemical testing and 14 patients determined not to have the condition had the 0.25 mg and standard 1 mg overnight DEX suppression test and the two-day low-dose DEX suppression tests. Our results show that morning serum cortisol and cortisol/DEX ratios following an overnight dexamethasone suppression test were similar in patients with Cushing's syndrome and those not having Cushing's syndrome. However, a morning cortisol value above 7.6 μg/dl following a dose of DEX of 0.25 mg was found in 12 patients with Cushing's syndrome and none in those not having Cushing's syndrome, suggesting that a high cortisol value after this low dose of dexamethasone can indicate that further testing for Cushing's syndrome is warranted. Our data suggest that the traditional 1 mg overnight or the 2 mg/2 day DEX suppression testing should no longer be used as a screening test in patients who could have mild and/or periodic Cushing's syndrome, while the 0.25 mg dose of DEX may pick up some patients with mild Cushing's syndrome.

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We report 3 adolescents with cannabis hyperemesis syndrome and recurrent hypophosphatemia complicating their clinical course with potential for significant consequences. They serve as reminders for providers to consider the diagnosis of cannabis hyperemesis syndrome and to monitor serum electrolytes closely in the setting of adolescent hyperemesis.

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