The performances of four multiplex PCR (m-PCR) were compared to direct immunofluorescence assay (DFA) and HuH7 cell culture for the detection of viruses in 263 children admitted to hospital with an acute respiratory illness. One hundred fifty (57.6%) nasal aspirates were found DFA-positive; 188 (72.3%) were found positive by both DFA and HuH7 cell culture, and 242 (92%) were PCR-positive. The m-PCR detected 124 viruses which were not found by conventional methods: 68 rhinovirus, 17 human metapneumovirus, 15 respiratory syncytial virus (RSV), 8 parainfluenza virus (PIV), 5 coronavirus 229E, 3 OC43 and 3 NL63, 4 enterovirus, 2 influenza virus B and C virus. The m-PCR were more sensitive, had the advantages of a shorter delay in specific diagnosis, and a lower cost than DFA and culture. Using these m-PCR, the prevalence of each virus was compared between in-patient and out-patient groups of children attending the emergency unit of the hospital. Nasal aspirates from 411 (91.5%) children were found positive by the PCRs. RSV, rhinovirus, and influenza virus were the most frequent viruses detected in this population, representing 43.6%, 31.8%, and 8.8% of the virus found, respectively, followed by human metapneumovirus (4.4%), coronavirus (3.4%), parainfluenza virus (3.2%), adenovirus (2.3%), and enterovirus (2.1%). RSVs were detected more significantly in the in-patient group than in the out-patient group, and influenza viruses were detected more frequently in the out-patient group than in the in-patient group. Moreover, the use of m-PCR pointed out the frequency of rhinovirus and mixed viral detections in these patients. In conclusion, according to the requirements of speed and low cost of the methods, and to achieve the highest rate of detection of respiratory viruses, the combined use of DFA and m-PCR is today likely to be the best way to improve diagnosis of respiratory illnesses in children.

Mutations in the ATP6V1B1 and ATP6V0A4 genes, encoding subunits B1 and 4 of apical H ؉ ATPase, cause recessive forms of distal renal tubular acidosis (dRTA). ATP6V1B mutations have been associated with early sensorineural hearing loss (SNHL), whereas ATP6V0A4 mutations are classically associated with either late-onset SNHL or normal hearing. The phenotype and genotype of 39 new kindreds with recessive dRTA, 18 of whom were consanguineous, were assessed. Novel and known loss-of-function mutations were identified in 31 kindreds. Fourteen new and five recurrent mutations of the ATP6V0A4 gene were identified in 21 families. For the ATP6V1B1 gene, two new and two previously described mutations were identified in 10 families. Surprisingly, seven probands with ATP6V0A4 gene mutations developed severe early SNHL between the ages of 2 mo and 10 yr. No mutation was detected in eight families. These data extend the spectrum of disease-causing mutations and provide evidence for genetic heterogeneity in SNHL. The data also demonstrate that mutations in either of these genes may cause early deafness, and they highlight the importance of genetic screening for recessive forms of dRTA independent of hearing status.

CYP24A1 biallelic mutations are frequently found in patients presenting with hypercalcemia, low PTH, and renal disease. We confirm the accuracy and effectiveness of a novel blood test estimating the ratio between relevant vitamin D metabolites as a useful screening tool for CYP24A1 mutations. Haploinsufficiency is not associated with CYP24A1 deficiency.

SummaryBackground and objectives Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is a rare autosomal recessive renal tubular disease. It is caused by mutations in CLDN16 and CLDN19, encoding claudin-16 and -19, respectively. Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is usually complicated by progressive CKD. The objectives of this study were to describe the clinical and genetic features of familial hypomagnesemia with hypercalciuria and nephrocalcinosis and analyze phenotype-genotype associations in patients with CLDN16 or CLDN19 mutations.Design, setting, participants, & measurements Data from 32 genetically confirmed patients (9 patients with CLDN16 and 23 patients with CLDN19 mutations) from 26 unrelated families were retrospectively reviewed.Results Diagnosis was based on clinical criteria at a median age of 9.5 years and confirmed by genetic testing at a median age of 15.5 years. In total, 13 CLDN16 or CLDN19 mutations were identified, including 8 novel mutations. A founder effect was detected for the recurrent CLDN16 p.Ala139Val mutation in North African families and the CLDN19 p.Gly20Asp mutation in Spanish and French families. CKD was more frequently observed in patients with CLDN19 mutations: survival without CKD or ESRD was 56% at 20 years of age in CLDN19 versus 100% in CLDN16 mutations (log rank P,0.01). Ocular abnormalities were observed in 91% of patients with CLDN19 mutations and none of the patients with CLDN16 mutations (P,0.01). Treatments seem to have no effect on hypercalciuria and CKD progression.Conclusions Patients with CLDN19 mutations may display more severe renal impairment than patients with CLDN16 mutations. Ocular abnormalities were observed only in patients with CLDN19 mutations.

Mutations in the NPHS2 gene encoding podocin are implicated in an autosomal-recessive form of nonsyndromic steroid-resistant nephrotic syndrome in both pediatric and adult patients. Patients with homozygous or compound heterozygous mutations commonly present with steroid-resistant nephrotic syndrome before the age of 6 years and rapidly progress to end-stage kidney disease with a very low prevalence of recurrence after renal transplantation. Here, we reviewed all the NPHS2 mutations published between October 1999 and September 2013, and also all novel mutations identified in our personal cohort and in international genetic laboratories. We identified 25 novel pathogenic mutations in addition to the 101 already described. The mutations are distributed along the entire coding region and lead to all kinds of alterations including 53 missense, 17 nonsense, 11 small insertions, 26 small deletions, 16 splicing, two indel mutations, and one mutation in the stop codon. In addition, 43 variants were classified as variants of unknown significance, as these missense changes were exclusively described in the heterozygous state and/or considered benign by prediction software. Genotype-phenotype analyses established correlations between specific variants and age at onset, ethnicity, or clinical evolution. We created a Web database using the Leiden Open Variation Database (www.lovd.nl/NPHS2) software that will allow the inclusion of future reports.