Lyme disease—another transfusion risk?

Lyme disease (or Lyme borreliosis) is caused by a spirochetal bacteria, Borrelia burgdorferi. Increased recognition of the disease and increased exposure to the vector (ticks) capable of spreading B. burgdorferi from animal hosts have resulted in a rise in the number of cases of Lyme borreliosis reported in the United States. There are three stages of the clinical course of Lyme borreliosis; however, not all those infected will have typical manifestations of each stage, such as the arthritis of the third stage. Routine blood cultures will rarely document bacteremia and serologic testing is not yet reliable. Early treatment can prevent later stages of Lyme borreliosis. There is evidence that transmission of B. burgdorferi by blood transfusion is possible, but, to date, there has been no documentation of transfusion- associated Lyme borreliosis. Thus, no new recommendations for screening donors to identify possible carriers of B. burgdorferi are suggested at this time.     

Childhood tumors of the brain: demographic pattern over a ten-year period in the Kashmir Valley

Brain tumors in children represent the second most frequent tumors in this age group after hematologic malignancies. We highlight the demographic pattern after retrospective analysis of brain tumors in children from geographically and ethnically distinct Kashmir Valley managed in our center between 2000 and 2009. We had a total of 248 pediatric patients with brain tumors. The parameters analyzed were age, gender, location of tumors and histopathological subtypes as well as WHO grade of tumor. We also did a comparison between the frequencies of common varieties of tumor in the first and second 5-year periods. We found that 111 tumors (44.75%) were supratentorial, and 137 (55.25%) were infratentorial. The male-to-female ratio was 1.4:1. The proportions of low-grade and high-grade tumors were 60 and 40%, respectively. The most common tumor in our series was astrocytoma. The most common tumors in the supratentorial and infratentorial compartments were craniopharyngioma and medulloblastoma, respectively. Our experience reflects a different demographic profile of pediatric brain tumors as compared with other regions of the world.     

DFNB79: reincarnation of a nonsyndromic deafness locus on chromosome 9q34.3

Genetic analysis of an inbred Pakistani family PKDF280, segregating prelingual severe to profound sensorineural hearing loss, provided evidence for a DFNB locus on human chromosome 9q34.3. Co-segregation of the deafness trait with marker D9SH159 was determined by a two-point linkage analysis (LOD score 9.43 at θ=0). Two additional large families, PKDF517 and PKDF741, co-segregate recessive deafness with markers linked to the same interval. Haplotype analyses of these three families refined the interval to 3.84 Mb defined by D9S1818 (centromeric) and D9SH6 (telomeric). This interval overlaps with the previously reported DFNB33 locus whose chromosomal map position has been recently revised and assigned to a new position on chromosome 10p11.23–q21.1. The nonsyndromic deafness locus on chromosome 9q segregating in family PKDF280 was designated DFNB79. We are currently screening the 113 candidate DFNB79 genes for mutations and have excluded CACNA1B, EDF1, PTGDS, EHMT1, QSOX2, NOTCH1, MIR126 and MIR602.     

Identification of MEN1 gene mutations in sporadic carcinoid tumors of the lung

Lung carcinoids occur sporadically and rarely in association with multiple endocrine neoplasia type 1 (MEN1). There are no well defined genetic abnormalities known to occur in these tumors. We studied 11 sporadic lung carcinoids for loss of heterozygosity (LOH) at the locus of the MEN1 gene on chromosome 11q13, and for mutations of the MEN1 gene using dideoxy fingerprinting. Additionally, a lung carcinoid from a MEN1 patient was studied. In four of 11 (36%) sporadic tumors, both copies of the MEN1 gene were inactivated. All four tumors showed the presence of a MEN1 gene mutation and loss of the other allele. Observed mutations included a 1 bp insertion, a 1 bp deletion, a 13 bp deletion and a single nucleotide substitution affecting a donor splice site. Each mutation predicts truncation or potentially complete loss of menin. The remaining seven tumors showed neither the presence of a MEN1 gene mutation nor 11q13 LOH. The tumor from the MEN1 patient showed LOH at chromosome 11q13 and a complex germline MEN1 gene mutation. The data implicate the MEN1 gene in the pathogenesis of sporadic lung carcinoids, representing the first defined genetic alteration in these tumors.      

High throughput parallel analysis of hundreds of patient samples for more than 100 mutations in multiple disease genes

As more mutations are identified in genes of known sequence, there is a crucial need in the areas of medical genetics and genome analysis for rapid, accurate and cost-effective methods of mutation detection. We have developed a multiplex allele-specific diagnostic assay (MASDA) for analysis of large numbers of samples (> 500) simultaneously for a large number of known mutations (> 100) in a single assay. MASDA utilizes oligonucleotide hybridization to interrogate DNA sequences. Multiplex DNA samples are immobilized on a solid support and a single hybridization is performed with a pool of allele-specific oligonucleotide (ASO) probes. Any probes complementary to specific mutations present in a given sample are in effect affinity purified from the pool by the target DNA. Sequence-specific band patterns (fingerprints), generated by chemical or enzymatic sequencing of the bound ASO(s), easily identify the specific mutation(s). Using this design, in a single diagnostic assay, we tested samples for 66 cystic fibrosis (CF) mutations, 14 beta-thalassemia mutations, two sickle cell anemia (SCA) mutations, three Tay-Sachs mutations, eight Gaucher mutations, four mutations in Canavan disease, four mutations in Fanconi anemia, and five mutations in BRCA1. Each mutation was correctly identified. Finally, in a blinded study of 106 of these mutations in > 500 patients, all mutations were properly identified. There were no false positives or false negatives. The MASDA assay is capable of detecting point mutations as well as small insertion or deletion mutations. This technology is amenable to automation and is suitable for immediate utilization for high-throughput genetic diagnostics in clinical and research laboratories.