Letal verlaufende Varizellen nach Nierentransplantation

Zusammenfassung Wir berichten über ein 7 Jahre altes M?dchen, das 14 Tage nach einer Nierentransplantation an Varizellen erkrankte. Erste Symptome waren krampfartige Bauchschmerzen mit radiologischen Hinweisen auf einen Obturationssubileus bei Obstipation. Als nach abführenden Ma?nahmen keine Besserung auftrat, wurde eine Probelaparotomie mit Entfernung des Tenckhoff-Dialysekatheters durchgeführt. Dabei zeigte sich kein pathologischer Befund, insbesondere fanden sich keine Briden. Zwei Tage nach Beginn der abdominalen Symptomatik trat ein zun?chst uncharakteristisches Exanthem auf. Aus den sich in den n?chsten 12 h entwickelnden Bl?schen konnte Varicella-Zoster-Virus isoliert werden. Trotz hochdosierter Gabe von Aciclovir und Varicella-Zoster-Immunglobulin entwickelte sich ein fulminantes Leberversagen mit Verbrauchskoagulopathie. Die Patientin verstarb am 18. postoperativen Tag trotz intensiver supportiver Therapie im Multiorganversagen. Diskussion: Vor dem Hintergrund dieser letalen Varizelleninfektion wird auf die Komplikationen und die teilweise untypischen Verl?ufe von Windpocken bei immunsupprimierten Kindern hingewiesen. Eine aktive Impfung ist daher bei seronegativen Patienten vor einer geplanten Organtransplantation zu fordern.      

SOS1 is the second most common Noonan gene but plays no major role in cardio-facio-cutaneous syndrome

Background

Heterozygous gain‐of‐function mutations in various genes encoding proteins of the Ras‐MAPK signalling cascade have been identified as the genetic basis of Noonan syndrome (NS) and cardio‐facio‐cutaneous syndrome (CFCS). Mutations of SOS1, the gene encoding a guanine nucleotide exchange factor for Ras, have been the most recent discoveries in patients with NS, but this gene has not been studied in patients with CFCS.

Methods and results

We investigated SOS1 in a large cohort of patients with disorders of the NS–CFCS spectrum, who had previously tested negative for mutations in PTPN11, KRAS, BRAF, MEK1 and MEK2. Missense mutations of SOS1 were discovered in 28% of patients with NS. In contrast, none of the patients classified as having CFCS was found to carry a pathogenic sequence change in this gene.

Conclusion

We have confirmed SOS1 as the second major gene for NS. Patients carrying mutations in this gene have a distinctive phenotype with frequent ectodermal anomalies such as keratosis pilaris and curly hair. However, the clinical picture associated with SOS1 mutations is different from that of CFCS. These findings corroborate that, despite being caused by gain‐of‐function mutations in molecules belonging to the same pathway, NS and CFCS scarcely overlap genotypically.     

Post-transplant epididymitis and orchitis following Listeria monocytogenes septicaemia

We report the occurrence of epididymitis and orchitis 1 week after the onset of Listeriosis in an 11-month-old boy receiving an orthotopic liver transplantation for biliary atresia. Immunologic implications of Listeria monocytogenes-induced testicular inflammation are discussed, and the potential role of immunosuppression with tacrolimus is also discussed.     

Complete remission of post-transplant FSGS recurrence by long-term plasmapheresis

Focal segmental glomerulosclerosis (FSGS) is known to recur in approximately 30% of renal allografts with graft loss in about half of these cases. The exact etiology remains unclear, though a putative circulating permeability factor or loss of inhibitory substances is being discussed. Different therapeutic approaches have been used. We report on a 10-year-old Arabian boy with a recurrence of FSGS immediately after transplantation. In addition to intensifying immunosuppressive therapy with high-dose cyclosporin A and cyclophosphamide, plasmapheresis was initiated and remission was achieved after 8 months. Three weeks after cessation of plasmapheresis a relapse occurred. Plasmapheresis was resumed and remission was achieved again after four additional sessions. The interval between plasmapheresis treatments was then gradually increased and fourteen months after transplantation plasmapheresis was stopped again. Since then (1.5 years after cessation of treatment) the patient has been in complete remission without any further episode of proteinuria. In conclusion, complete and sustained remission with stable renal function was achieved in our patient by long-term plasmapheresis in combination with intensified immunosuppression. Therefore, continuation of plasmapheresis treatment should be considered even in the situation of initial non-response.     

Genetic analysis: a diagnostic tool for primary hyperoxaluria type 1

Pediatric Nephrology -     

Maldescent of the testes—an epidemiological study

The case histories of 2,362 newborn boys were evaluated for congenital testicular maldescent. These data, obtained from the prospective follow-up study Pregnancy and Child Development sponsored by the Deutsche Forschungsgemeinschaft, are discussed in the light of new findings on morphological changes in this disorder.The aetiology of maldescent of testes is considered to be heterogenous and could not be clarified by investigating 26 factors which might be regarded as possible causes of the abnormality.The difficulties in achieving a correct classification of the various forms of maldescended testes are emphasized and are demonstrated by data from this collaborative study.Considering the frequency of non-descent at the ages of 9 months (3.3%), 18 months (2.9%), and 36 months (2.5%), we believe we have found some evidence for spontaneous descent in a proportion of cases during the first 3 years of life. If this is confirmed by proposed new studies, the findings will have to be weighed against the recommendations of the 1974 International Health Foundation that therapy should be performed during the 2nd year of life or earlier.     

Nephrocystin specifically localizes to the transition zone of renal and respiratory cilia and photoreceptor connecting cilia

Nephronophthisis (NPHP) is a hereditary cystic kidney disorder that causes renal failure in children and young adults and can be associated with various extrarenal disorders, including retinitis pigmentosa. Six NPHP genes, whose functions are disrupted by autosomal recessive mutations in patients with NPHP, have been identified. The majority of patients with NPHP carry homozygous deletions of NPHP1 encoding nephrocystin. Previous data indicate that nephrocystin forms a complex at cell junctions and focal adhesions. Here, it is shown that nephrocystin specifically localizes at the ciliary base to the transition zone of renal and respiratory cilia and to photoreceptor connecting cilia. During in vitro ciliogenesis of primary human respiratory epithelial cells, nephrocystin can be detected first with a diffuse cytoplasmic localization as soon as cell polarization starts, and translocates to the transition zone when cilia are formed. In columnar respiratory cells, nephrocystin is attached tightly to the axonemal structure of the transition zone at a region that contains the calcium-sensitive cilia autotomy site. In patients with homozygous NPHP1 deletions, nephrocystin is absent from the entire respiratory cell, including the transition zone, which might be of interest for future diagnostic approaches. Cilia formation is not altered in primary nephrocystin-deficient respiratory cells, which is consistent with previous findings obtained for the Caenorhabditis elegans ortholog. In addition, it is shown that the localization pattern of intraflagellar transport proteins and nephrocystin differs, suggesting distinct functional roles. In conclusion, nephrocystin deficiency or dysfunction at the transition zone of renal monocilia and the photoreceptor connecting cilium might explain renal failure and retinal degeneration that are observed in patients with NPHP1.