The DiGeorge syndrome, the most common of the microdeletion syndromes, affects multiple organs, including the heart, the nervous system, and the kidney. It is caused by deletions on chromosome 22q11.2; the genetic driver of the kidney defects is unknown. We conducted a genomewide search for structural variants in two cohorts: 2080 patients with congenital kidney and urinary tract anomalies and 22,094 controls. We performed exome and targeted resequencing in samples obtained from 586 additional patients with congenital kidney anomalies. We also carried out functional studies using zebrafish and mice. We identified heterozygous deletions of 22q11.2 in 1.1% of the patients with congenital kidney anomalies and in 0.01% of population controls (odds ratio, 81.5; P=4.5×10⁻¹⁴). We localized the main drivers of renal disease in the DiGeorge syndrome to a 370-kb region containing nine genes. In zebrafish embryos, an induced loss of function in snap29, aifm3, and crkl resulted in renal defects; the loss of crkl alone was sufficient to induce defects. Five of 586 patients with congenital urinary anomalies had newly identified, heterozygous protein-altering variants, including a premature termination codon, in CRKL. The inactivation of Crkl in the mouse model induced developmental defects similar to those observed in patients with congenital urinary anomalies. We identified a recurrent 370-kb deletion at the 22q11.2 locus as a driver of kidney defects in the DiGeorge syndrome and in sporadic congenital kidney and urinary tract anomalies. Of the nine genes at this locus, SNAP29, AIFM3, and CRKL appear to be critical to the phenotype, with haploinsufficiency of CRKL emerging as the main genetic driver. (Funded by the National Institutes of Health and others.)

Introduction: Urinary tract infection (UTI) occurs in 1.1% of girls and 1.4% of boys during the first year of life. Asymptomatic bacteriuria (ABU) is usually detected incidentally in 0.9% of girls and 2.5% of boys at this age. The aim of the study was to assess the usefulness of measurement of pro-inflammatory urine interleukin (IL)-6 and IL-8 concentrations and anti-inflammatory transforming growth factor 1 (TGF-1) level in infants with febrile UTI, non-febrile UTI and ABU. Material and methods: A total of 35 children, mean age 6.14 ±3.47 months, were divided into three groups: group I – febrile UTI (n = 13), group II – non-febrile UTI (n = 13) and group III – ABU (n = 9). At the time of enrollment urine IL-6, IL-8, TGF-β1 and serum C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and white blood cell count (WBC) were measured. Renal ultrasound was performed in all children, 99mTc-dimercaptosuccinic acid scintigraphy (DMSA) and voiding cystourethrography in children with UTI. Results: Urine concentrations of IL-6 and IL-8 were significantly higher in febrile UTI compared to those with non-febrile UTI and ABU (p < 0.5, p < 0.01) and positively correlated with CRP, ESR and WBC (p < 0.01). Urine levels of TGF-β1 were significantly higher in children with febrile UTI compared to those with ABU (p < 0.05) and positively correlated with WBC (p < 0.01). Inflammatory changes in the DMSA scan were detected in 66.6% of children with UTI. No significant difference in frequency of an abnormal DMSA scan compared to a normal scan was found in groups with febrile and non-febrile UTI. No relations between urine cytokines, systemic inflammatory markers and changes in DMSA scan were observed. The cutoff value for detection of inflammatory changes in the DMSA scan for IL-8 was 120 pg/mg creatinine (Cr) and 40 pg/mg Cr for TGF-β1. Based on this value, the sensitivity for IL-8 was 58.3%, specificity 100% and for TGF-β1 66.7% and 83.7%, respectively. Conclusions: We found significant differences in children with febrile UTI and ABU regarding urine IL-6, IL-8 and TGF-β1 levels. Urine cytokines and systemic inflammatory markers do not differentiate between upper and lower UTI in infants.

Mycoplasma pneumoniae is one of the most common causes of respiratory tract infections in children. Extrapulmonary manifestations are seen in up to 25% of infected patients. Extrapulmonary complications are associated with the central nervous system, gastrointestinal tract, skin changes, myocarditis, pericarditis, hemolytic anemia, thrombocytopenia and thrombosis. The majority of extrapulmonary symptoms are associated with skin changes such as exanthematous skin eruptions, erythema nodosum, urticaria, Stevens-Jonson syndrome. M. pneumoniae stimulates production of the interleukins and tumor necrosis factor (TNF)  and can cause vasculitis. Henoch-Schönlein purpura (HSP) is a leucoclastic vasculitis that affects small vessels. Clinical manifestations of HSP include typical rash, arthritis, gastrointestinal and sometimes renal involvement. The main feature in HSP is abnormal IgA deposits in vessel walls. Circulating abnormal glycosylated IgA 1 and IgG antibodies form immune complexes: IgA1-IgG and anti-IgA 1. Immune complexes activate cytokines, parts of complement and influence directly the endothelium. We report cases of three children with Henoch-Schönlein purpura with prolonged and recurrent skin and joint changes. The serological analysis (positive serum IgM) confirmed Mycoplasma pneumoniae infection. Treatment with clarithromycin caused complete regression of disease. We suggest that in the case of prolonged symptoms of vasculitis due to Henoch-Schönlein purpura, Mycoplasma pneumonia infection may be a potential cause of exacerbation of the disease.