A midface swelling in a child – A possible diagnostic dilemma

A lump on the midface of a child can pose as a diagnostic dilemma. There is a wide variety of possible differential diagnoses, ranging from simple benign conditions such as a sebaceous cyst, dermoid cyst, lipoma, neuroma and neurofibroma, to potentially devastating conditions such as odontogenic myxoma.A case of a child in which the formulation of a definite diagnosis was clinically and histologically challenging is presented.     

Common variants modify the age of onset for basal cell carcinomas in Gorlin syndrome

Gorlin syndrome is an autosomal dominant disorder, characterized by multiple early-onset basal cell carcinomas (BCCs) and jaw keratocysts. Through association studies in cohorts of sporadic BCC, nine genetic variants have previously been identified to increase the risk of BCC. The nine SNPs were genotyped by Taqman allelic discrimination in 125 individuals with Gorlin syndrome. Kaplan–Meier survival curves and Cox proportional-Hazard regression analysis were applied to determine the association between genotypes and age of first BCC in individuals with Gorlin syndrome. The p.(Arg151Cys) variant in MC1R (rs1805007) was associated with an earlier median age of onset of BCC of 27 years (95% CI: 20–34) compared with 34 years (95% CI: 30–40) for wild-type individuals (hazard ratio (HR)=1.64, 95% CI: 1.04–2.58, P=0.034). The risk allele of the variant at the chromosome 5p15 locus encompassing TERT-CLPTM1L (rs401681) was also associated with an earlier median onset of BCC, 31 years (95% CI: 28–37) compared with 41 years (95% CI: 32–48, HR=1.44, 95% CI: 1.08–1.93, P=0.014). In individuals with a risk allele at either rs1805007 or rs401681 the median time to BCC was 31 years of age (95% CI: 28–34) compared with 44 years of age (95% CI: 38–53) in wild-type individuals (HR=2.48, 95% CI: 1.47–4.17, P=0.0002). Our findings may have implications for future personalized risk estimates and BCC screening strategies in individuals with Gorlin syndrome.     

Loss of angiotensin-converting enzyme-2 (Ace2) accelerates diabetic kidney injury

Diabetic nephropathy is one of the most common causes of end-stage renal failure, but the factors responsible for the development of diabetic nephropathy have not been fully elucidated. We examined the effect of deletion of the angiotensin-convert-ing enzyme 2 (Ace2) gene on diabetic kidney injury. Ace2(-/-) mice were crossed with Akita mice (Ins2(WT/C96Y)), a model of type 1 diabetes mellitus, and four groups of mice were studied at 3 months of age: Ace2(+/y)Ins2(WT/WT), Ace2(-/y)Ins2(WT/WT), Ace2(+/y) Ins2(WT/C96Y), and Ace2(-/y)Ins2(WT/C96Y). Ace2(-/y) Ins2(WT/C96Y) mice exhibited a twofold increase in the urinary albumin excretion rate compared with Ace2(+/y)Ins2(WT/C96Y) mice despite similar blood glucose levels. Ace2(-/y)Ins2(WT/C96Y) mice were the only group to exhibit increased mesangial matrix scores and glomerular basement membrane thicknesses compared with Ace2(+/y)Ins2(WT/WT) mice, accompanied by increased fibronectin and alpha-smooth muscle actin immunostaining in the glomeruli of Ace2(-/y) Ins2(WT/C96Y) mice. There were no differences in blood pressure or heart function to account for the exacerbation of kidney injury. Although kidney levels of angiotensin (Ang) II were not increased in the diabetic mice, treatment with an Ang II receptor blocker reduced urinary albumin excretion rate in Ace2(-/y)Ins2(WT/C96Y) mice, suggesting that acceleration of kidney injury in these mice is Ang II-mediated. We conclude that ACE2 plays a protective role in the diabetic kidney, and ACE2 is an important determinant of diabetic nephropathy.     

S4153R Is a Gain-of-Function Mutation in the Cardiac Ca Release Channel Ryanodine Receptor Associated With Catecholaminergic Polymorphic Ventricular Tachycardia and Paroxysmal Atrial Fibrillation

Mutations in ryanodine receptor 2 (RYR2) gene can cause catecholaminergic polymorphic ventricular tachycardia (CPVT). The novel RYR2-S4153R mutation has been implicated as a cause of CPVT and atrial fibrillation. The mutation has been functionally characterized via store-overload-induced Ca²⁺ release (SOICR) and tritium-labelled ryanodine ([³H]ryanodine) binding assays. The S4153R mutation enhanced propensity for spontaneous Ca²⁺ release and reduced SOICR threshold but did not alter Ca²⁺ activation of [³H]ryanodine binding, a common feature of other CPVT gain-of-function RYR2 mutations. We conclude that the S4153R mutation is a gain-of-function RYR2 mutation associated with a clinical phenotype characterized by both CPVT and atrial fibrillation.     

Acute coronary thrombosis in a patient with diabetes and severe hyperglycemia

The pathophysiological processes responsible for acute coronary events in diabetic patients, in addition to the conventional factors associated with plaque rupture, include an enhanced prothrombotic state. This enhanced prothrombotic state results from multiple abnormalities of the coagulation system including platelet activation, impaired fibrinolysis and increased activity of the coagulation cascade. Studies have also demonstrated that severe hyperglycemia can result in an exacerbation of the underlying prothrombotic state, indicating that patients with extreme hyperglycemia are subject to an even greater thrombotic risk. The present case illustrates the thrombotic hazards associated with severe hyperglycemia.