Megacystis, megacolon, and malrotation: a new syndromic association?

Chronic intestinal pseudo-obstruction (CIPO) can occur as a consequence of neuropathies including diffuse Intestinal Neuronal Dysplasia (IND), a relatively rare enteric nervous system (ENS) abnormality. Although various authors reported of diffuse IND associated either with intestinal malrotation or megacystis, the co-existence of these three entities in the same patient has never been described before. The aim of this paper is to report for the first time in literature a series of patient with such association, focusing on one who carries a de novo duplication of chromosome 12, suggesting a new syndromic association (megacolon, megacystis, malrotation).

Clinical presentation and pathogenesis of cold-induced autoinflammatory disease in a family with recurrence of an NLRP12 mutation.

OBJECTIVE: NLRP12 mutations have been described in patients affected with peculiar autoinflammatory symptoms. This study was undertaken to characterize NLRP12 mutations in patients with autoinflammatory syndromes, particularly a novel missense mutation, p.D294E, affecting a protein sequence crucial for ATP binding, which was identified in a Caucasian family with familial cold-induced autoinflammatory syndrome in some family members. METHODS: Fifty patients were tested for NLRP12 mutations. A Caucasian family with the p.D294E missense mutation of NLRP12 in some family members was clinically characterized. In vitro analysis of the effects of the mutation on NF-κB activity was performed in HEK 293 cells after cotransfection of the cells with a luciferase NF-κB-responsive element and mutant or wild-type (WT) NLRP12 expression plasmids. NF-κB activity was also evaluated 24 hours after stimulation with tumor necrosis factor α in monocytes from individual family members carrying the mutation. Furthermore, secretion of interleukin-1ß (IL-1ß), production of reactive oxygen species (ROS), and activation of antioxidant systems in patient and healthy donor monocytes, under resting conditions and after stimulation with pathogen-associated molecular patterns (PAMPs), were also assessed. RESULTS: In the family assessed, the p.D294E mutation segregated in association with a particular sensitivity to cold exposure (especially arthralgias and myalgia), but not always with an inflammatory phenotype (e.g., urticarial rash or fever). In vitro, the mutant protein maintained the same inhibitory activity as that shown by WT NLRP12. Consistently, NLRP12-mutated monocytes showed neither increased levels of p65-induced NF-κB activity nor higher secretion of IL-1ß. However, the kinetics of PAMP-induced IL-1ß secretion were significantly accelerated, and high production of ROS and up-regulation of antioxidant systems were demonstrated. CONCLUSION: Even with a variable range of associated manifestations, the extreme sensitivity to cold represents the main clinical hallmark in an individual carrying the p.D294E mutation of the NLRP12 gene. Although regulation of NF-κB activity is not affected in patients, redox alterations and accelerated secretion of IL-1ß are associated with this mild autoinflammatory phenotype.

Search for pathogenetic variants of the SPRY2 gene in intestinal innervation defects.

SPRY2 is an inducible inhibitor of signalling mediated by tyrosine kinases receptors, whose targeting causes intestinal hyperganglionosis in mice. In this light, we have undertaken a mutational analysis of the SPRY2 gene in patients affected with intestinal neuronal dysplasia (IND), without detecting nucleotide changes in any of the 26 DNA samples analysed, with the exception of two already known polymorphic variants. A role of the SPRY2 gene in IND pathogenesis can be thus excluded.

PHOX2A and PHOX2B genes are highly co-expressed in human neuroblastoma.

The detection of PHOX2B mutations in a small proportion of patients affected with either familial or sporadic neuroblastoma (NB), has arisen interest on the possible pathogenic role of this gene in the disease determination. In this light, we have carried out a quantitative expression analysis of PHOX2B and its paralogue PHOX2A on a panel of NB cell lines and NB tumour samples to identify a possible differential expression between NB cells and their normal counterpart (adrenal medulla cells). Our results revealed that both PHOX2A and PHOX2B are over-expressed in tumour samples and NB cell lines. Particularly, the expression levels of the two genes in NB cell lines show a highly significant correlation, suggesting their possible synergistic role or a coordinated expression regulation. Furthermore, PHOX2 gene over-expression in NB tumours and cell lines suggests these genes may be widely involved in NB development through either a direct mechanism of up-regulation or a failure in maintaining proper transcript levels after embryonic development.