Discovery of Streptococcus pneumoniae serogroup 35 variants in Australian patients.

OBJECTIVES: Streptococcus pneumoniae isolates from Australian invasive pneumococcal disease cases displaying an atypical 35B phenotype. Whole genome sequencing was used to analyse these strains and identify changes to the capsule gene regions. METHODS: Four atypical serogroup 35 isolates from Australian reference laboratories were unable to be assigned to one of the four known group 35 serotypes by the Quellung serotyping method. Genetic characterization of the capsule locus was performed by bioinformatic analysis of whole genome sequencing data for all isolates. RESULTS: Genetic analysis identified four independent disruptions to the wciG gene, which encodes an O-acetyltransferase responsible for the O-acetylation of the 6Galß1 residue in the capsular polysaccharide repeat unit of serotype 35B. CONCLUSIONS: This is the first published report on the incidence and capsular gene characteristics of a S. pneumoniae 35B variant.

Detection of Y-chromosome in gonadal tumours using fluorescence in situ hybridization: diagnostic value in intersex conditions including older patients with clinically unsuspected androgen insensitivity syndrome.

AIMS: To evaluate fluorescence in situ hybridization (FISH) for SRY, the testis-determining gene on the Y-chromosome, in gonadal specimens from patients with intersex disorders including two older individuals presenting with Sertoli cell adenomas and clinically unsuspected androgen insensitivity syndrome (AIS). METHODS AND RESULTS: FISH, using probes for SRY and the X-centromere, was performed on two Sertoli cell adenomas presenting as ovarian masses in phenotypic females aged 62 and 73 years with previously undiagnosed AIS. Gonadal biopsies and tumours from eight additional patients with known intersex disorders and XY phenotype were also studied. Signal for SRY was demonstrated in at least one specimen from all patients, and from 16/18 (89%) specimens overall. The specificity of FISH was determined by analysis of 10 sporadic ovarian tumours including six dysgerminomas and four Sertoli-Leydig cell tumours: all cases expressed a female XX chromosomal signal. CONCLUSIONS: The demonstration of SRY using FISH is useful in the assessment of gonadal specimens from patients with intersex disorders, particularly in older individuals where the diagnosis may be unsuspected clinically. However, it may be necessary to examine multiple specimens in some cases to confirm the presence of Y-chromosomal material.

Severe gamma-sarcoglycanopathy caused by a novel missense mutation and a large deletion.

We report two siblings with a relatively severe limb-girdle muscular dystrophy. The elder sister presented at 8 years of age with inability to climb and abnormal gait. At 12 years she was barely ambulant. Her sister followed a similar course. Serum creatine kinase was 8500-10000 IU (N 25-200) in the elder sister and 17000-19000 IU in the younger sister. Muscle biopsy of the elder sister at 8 years showed chronic myopathic changes with loss of muscle fibres, active necrosis and regeneration. Immunocytochemistry demonstrated normal spectrin and dystrophin, reduced alpha-sarcoglycan and absent gamma-sarcoglycan--indicating a gamma-sarcoglycanopathy. Haplotype analysis for the markers D13S115, D13S232, D13S292, D13S787, D13S1243 and D13S283 internal to and flanking the gamma-sarcoglycan gene showed the affected sisters shared haplotypes, indicating it was possible they were suffering from a gamma-sarcoglycanopathy. Non-inheritance of paternal alleles for D13S232, D13S292 and D13S1243 suggested the inheritance of a deletion, which was confirmed by FISH, using a genomic probe from the gamma-sarcoglycan gene. The gamma-sarcoglycan cDNA was amplified by reverse transcriptase PCR from the muscle biopsy of the elder sister and sequenced. A missense mutation changing codon 69 from GGC glycine to CGC arginine was identified. HhaI digestion of exon 3 genomic PCR products showed the two affected sisters were hemizygous for the mutation, while the mother and grandmother were heterozygotes. The mutation, identified by SSCP analysis, was not observed in 116 unrelated, unaffected individuals. Previously, only two other missense mutations, the Cys283Tyr missense mutation in Gypsies and the Leu193Ser mutation in a Dutch family, have been described in the gamma-sarcoglycan gene. The fact that the affected individuals in the current and Gypsy families are gamma-sarcoglycan negative may indicate that codons 69 and 283 are important in gamma-sarcoglycan function.

Identification of a novel deletion of the entire OCRL1 gene detected by FISH analysis in a family with Lowe syndrome.

The oculocerebrorenal syndrome of Lowe (OCRL) is a rare X-linked multisystem disorder affecting the lens, kidney and brain. The gene involved (OCRL1) has been identified and is known to encode a phosphatidylinositol 4,5-bisphosphate 5-phosphatase. Mutations in OCRL1 have been shown to be causative of OCRL. To date, most of the mutations identified have consisted of simple or point mutations and there is one report of a 1.4-kb deletion. We investigated the OCRL1 gene in a male patient with OCRL by the polymerase chain reaction and found that the entire OCRL1 gene was deleted. Fluorescence in situ hybridisation analysis (FISH), with cosmid probes that span the entire OCRL1 gene, was used to confirm this deletion and subsequently identify it in the proband's mother. This is the first report of a whole gene deletion of OCRL1 and thus expands the range of mutations that give rise to OCRL. The use of the FISH technique facilitated carrier and prenatal testing for the deletion in the family.

The ratio of X- and Y-bearing sperm in ejaculates of men with three or more children of the same sex.

PURPOSE: The present study evaluated the proportions of X-bearing and Y-bearing sperm within the semen of donors who were the declared fathers of three or more sons or daughters. METHODS: The proportions of sperm were determined using dual-color fluorescence in situ hybridization to identify the X and Y chromosomes. RESULTS: The only difference observed was in semen volume. There was no increase in the proportion of Y-bearing sperm for men with only sons (49.7 +/- 1.3%) or of X-bearing sperm for men with only daughters (44.8 +/- 2.6%). CONCLUSIONS: A preponderance of either sons or daughters in a family cannot be explained simply by an altered ratio of X-bearing and Y-bearing sperm in the father's semen.