Molecular cloning and characterization of bovine PRKAG3 gene: structure, expression and single nucleotide polymorphism detection

The protein kinase adenosine monophosphate-activated gamma3-subunit (PRKAG3) gene encodes a muscle-specific isoform of the regulatory gamma-subunit of adenosine monophosphate-activated protein kinase, which plays a key role in regulating energy homeostasis in eucaryotes. It is well known that mutations in the PRKAG3 gene affect high glycogen content in the porcine skeletal muscle and, consequently, meat quality. The genomic structure and sequence of the bovine PRKAG3 were analysed from a Korean cattle BAC clone. The bovine PRKAG3 gene comprises 13 exons and spans approximately 6.8 kb on BTA2. From 5' and 3'-rapid amplification of cDNA ends experiments, the full-length cDNA of bovine PRKAG3 has been identified, encoding a deduced protein of 465 amino acids. Two splice isoforms, generated by the alternative splicing of exon 2, were also identified. Northern blot analysis demonstrated that, similar to other species, the bovine PRKAG3 transcript was only expressed in skeletal muscle. Seven single nucleotide polymorphisms, including two previously identified variants, were detected in four Bos taurus cattle breeds. The bovine PRKAG3 gene described in this study may be involved in muscle-related genetic diseases or meat quality traits in cattle.

Uterine artery embolisation for symptomatic fibroids in a tertiary hospital in Singapore

INTRODUCTION

Transcatheter uterine artery embolisation (UAE) for the treatment of symptomatic uterine enlargement due to fibroids has been performed in several overseas centres with promising results. We report our experience with UAE in Singapore General Hospital.

MATERIALS AND METHODS

Twenty women with symptomatic uterine fibroids who declined surgery were treated by transcatheter UAE. The uterine arteries were selectively catheterised and embolised with polyvinyl alcohol particles. Post-procedure analgesia was administered via a patient-controlled analgesia pump. The patients were followed up at regular intervals clinically and with transabdominal ultrasonography.

RESULTS

Transcatheter UAE was performed on all patients with no major complications. Nineteen patients had both uterine arteries embolised while 1 patient had only the right uterine artery embolised on account of hypoplasia of the left uterine artery. The mean hospital stay was 3.5 days (range, 2 to 9). At a mean follow-up of 56 weeks (range, 6 to 168), all patients reported improvements in their presenting symptoms. Objective improvement in terms of reduction of uterine and fibroid sizes was determined on ultrasonography. The median size of the uterine volume decreased from 308 to 187 mL while the median diameter of the largest fibroid reduced from 6.2 to 4.6 cm. The median haemoglobin level increased to 12.7 g/dL from the pre-procedural median of 9.9 g/dL. One patient, who initially responded with a decrease in uterine and dominant fibroid size, became symptomatic (menorrhagia) at 6 months post-embolisation. She underwent a repeat procedure with complete resolution of symptoms. A second patient had recurrence of symptoms at 12 months, but was subsequently lost to follow-up.

CONCLUSION

Mid-term results of UAE for the treatment of symptomatic fibroids in our hospital indicate this to be a safe and effective therapeutic option.

A survey of fasting during pregnancy

INTRODUCTION

Fasting during the month of Ramadan is compulsory in the Muslim faith. Although pregnant women may be exempted, many still choose to fast while others are more careful in practising it. This survey examines the practice of fasting among pregnant Muslim women in Singapore based on the prevalence in relation to factors such as parity, social and economic circumstances. It also analyses the factors that influence the decision to fast and the successful completion of the fast, and examines their knowledge, belief and attitudes on fasting during the holy month of Ramadan.

METHODS

This is a retrospective study of all Muslim women who were pregnant and received antenatal care in our hospital during the month of Ramadan from 17 November 2001 to 16 December 2001. A four-page questionnaire was mailed to all eligible subjects in March 2002.

RESULTS

Of 202 eligible subjects, 125 responded via mail and 57 via the phone, yielding a response rate of 90 percent. Most women chose to fast during pregnancy, and they do so with adequate support from their spouses and family members. Most of them do not experience any adversities during fasting and even if they do, most were able to overcome them. Most women adopt a positive attitude towards fasting. However, there is a lack of basic religious knowledge among many pregnant women pertaining to the Muslim law of fasting during pregnancy.

CONCLUSION

Doctors and health workers need to understand the religious obligations of a Muslim towards fasting during Ramadan. Only through this can a doctor adequately counsel Muslim patients and allow informed decision with regards to fasting. With respect to pregnant women, provisions are allowed for them not to observe fasting.

Investigating the infertile couple

INTRODUCTION

Investigations play a pivotal role in the workup for infertility. The results must be interpreted carefully as these assess dynamic function. Evidence-based guidelines are useful in the selection of appropriate tests.

MATERIALS AND METHODS

A review of current evidence-based guidelines for the investigation and management of the infertile couple is undertaken.

RESULTS

The main areas that correlate with fecundability are ovulatory function, tubal patency and semen analysis.

CONCLUSION

The appropriate selection of investigations based on problem areas identified by history and physical examination would guide the physician in the management of the infertile couple.

Requirement for yeast RAD26, a homolog of the human CSB gene, in elongation by RNA polymerase II

Mutations in the human CSB gene cause Cockayne syndrome (CS). In addition to increased photosensitivity, CS patients suffer from severe developmental abnormalities, including growth retardation and mental retardation. Whereas a deficiency in the preferential repair of UV lesions from the transcribed strand accounts for the increased photosensitivity of CS patients, the reason for developmental defects in these individuals has remained unclear. Here we provide in vivo evidence for a role of RAD26, the counterpart of the CSB gene in Saccharomyces cerevisiae, in transcription elongation by RNA polymerase II, and in addition we show that under conditions requiring rapid synthesis of new mRNAs, growth is considerably reduced in cells lacking RAD26. These findings implicate a role for CSB in transcription elongation, and they strongly suggest that impaired transcription elongation is the underlying cause of the developmental problems in CS patients.

[Study on computer aided design system of anterior prosthesis in terms of artificial neural network]

OBJECTIVE

This study was to develop computer aided design system of anterior prosthesis, which can improve information communication among doctors, technicians, patients and raise anterior prosthesis cosmetic effect.

METHODS

Digital camera was used for image capture; Space field method, neighboring field average method, midst value filter method, and image average method were used for image pre-process; sample teeth were constructed; anterior prosthesis were automatically designed through tooth feature extraction.

RESULTS

86 patients were prosthetically designed through this CAD system with excellent results.

CONCLUSION

This system implemented anterior prosthesis CAD rapidly, guided clinical application and promoted information process in the field of prosthetics.

Effects of chilling on sampling of bacteria attached to swine carcasses

Two microbiological sampling techniques, excision and sponge swabbing, were compared by determining counts of aerobic bacteria, coliforms and injured coliforms from 20 de-haired swine carcasses before and after chilling. Excised jowl skin produced significantly greater counts of the three types of bacteria than sponge swabs. Aerobic bacteria, coliforms and injured coliforms recovered by sponge swabbing carcasses before chilling were 11.6%, 0.9% and 11.0% of excised samples, respectively; the corresponding percentages recovered after chilling were 23.9%, 11.1% and 5.0%. Numbers of all bacteria present on the post-chill carcasses were substantially lower than on the pre-chill carcasses. Excision usually produced more countable plates for coliforms and injured coliforms on chilled carcasses than sponge swabbing and therefore, is more suitable in estimating low numbers of faecal bacteria on chilled carcasses. To explore the possible structural bases for these findings, skin samples were inoculated with 10(2)-10(7) cfu cm(-2) faecal bacteria and examined by scanning electron microscopy. Chilled samples showed bacteria and biofilm embedded in superficial crevices, which underlies a possible reason for the lower recovery of bacterial cells by the sponge swabbing. The study indicates that the differences between sampling techniques may be a result of the chilling process of swine carcasses.

Variability in CD34+ cell counts in umbilical cord blood: implications for cord blood transplants

OBJECTIVE

To determine if total nucleated cell counts alone are sufficient for predicting the efficacy of cord blood units for transplant from neonatal umbilical cord blood samples.

METHODS

Umbilical cord blood samples were collected from 200 mothers at delivery and the cord blood units processed. The total nucleated cells and CD34+ cells were enumerated and compared for each sample.

RESULTS

Despite an apparent linear correlation between total nucleated cell counts and CD34+ cell counts, each group of total nucleated cell counts demonstrated a high degree of variation in CD34+ cell counts and could be as low as 0.1% of total nucleated cell counts.

CONCLUSIONS

Large variations in CD34+ cell counts per total nucleated cell count are present for cord blood units from neonatal umbilical cord samples. Hence a CD34+ cell count for each cord blood unit would improve selection of samples for transplant.

Requirement of DNA polymerase eta for error-free bypass of UV-induced CC and TC photoproducts

The yeast RAD30-encoded DNA polymerase eta (Poleta) bypasses a cis-syn thymine-thymine dimer efficiently and accurately. Human DNA polymerase eta functions similarly in the bypass of this lesion, and mutations in human Poleta result in the cancer prone syndrome, the variant form of xeroderma pigmentosum. UV light, however, also elicits the formation of cis-syn cyclobutane dimers and (6-4) photoproducts at 5'-CC-3' and 5'-TC-3' sites, and in both yeast and human DNA, UV-induced mutations occur primarily by 3' C to T transitions. Genetic studies presented here reveal a role for yeast Poleta in the error-free bypass of cyclobutane dimers and (6-4) photoproducts formed at CC and TC sites. Thus, by preventing UV mutagenesis at a wide spectrum of dipyrimidine sites, Poleta plays a pivotal role in minimizing the incidence of sunlight-induced skin cancers in humans.

A case report on vesico-uterine fistula: a very rare complication of the lower caesarean section

Vesico-uterine fistula is a very rare complication of lower caesarean section. There has only been two cases seen at the Department of Urology in the past 2 decades. Patients usually present in the early post operative period with the problem of continuous urinary incontinence. On the rare occasion, recurrent urinary tract infection, recurrent gross painless haematuria, or secondary infertility associated with secondary amenorrhoea would be the presenting complaint.

Characterization of the distal tail fiber locus and determination of the receptor for phage AR1, which specifically infects Escherichia coli O157:H7

Phage AR1 is similar to phage T4 in several essential genes but differs in host range. AR1 infects various isolates of Escherichia coli O157:H7 but does not infect K-12 strains that are commonly infected by T4. We report here the determinants that confer this infection specificity. In T-even phages, gp37 and gp38 are components of the tail fiber that are critical for phage-host interaction. The counterparts in AR1 may be similarly important and, therefore, were characterized. The AR1 gp37 has a sequence that differs totally from those of T2 and T4, except for a short stretch at the N terminus. The gp38 sequence, however, has some conservation between AR1 and T2 but not between AR1 and T4. The sequences that are most closely related to the AR1 gp37 and gp38 are those of phage Ac3 in the T2 family. To identify the AR1-specific receptor, E. coli O157:H7 was mutated by Tn10 insertion and selected for an AR1-resistant phenotype. A mutant so obtained has an insertion occurring at ompC that encodes an outer membrane porin. To confirm the role of OmpC in the AR1 infection, homologous replacement was used to create an ompC disruption mutant (RM). When RM was complemented with OmpC originated from an O157:H7 strain, but not from K-12, its AR1 susceptibility was fully restored. Our results suggest that the host specificity of AR1 is mediated at least in part through the OmpC molecule.

Brief report: speed of information processing in children with insulin-dependent diabetes mellitus

OBJECTIVE

To determine whether children with insulin-dependent diabetes mellitus (IDDM) process information more slowly than children who do not have diabetes.

METHODS

We tested 31 children with early onset and longer duration of IDDM, 35 with later onset and briefer duration of IDDM, and 36 comparison children without diabetes. They were administered five tasks requiring rapid responding that assessed a range of cognitive processes.

RESULTS

On most tasks, children in the three groups were quite similar in the accuracy and speed of performance. Furthermore, for children in the diabetic groups, disease-related variables were unrelated to accuracy and speed of performance.

CONCLUSIONS

The results suggest that children with IDDM do not have a pervasive deficit in speed of information processing, although more circumscribed deficits in processing speed are possible.

Efficient and accurate replication in the presence of 7,8-dihydro-8-oxoguanine by DNA polymerase eta

Oxidative damage to DNA has been proposed to have a role in cancer and ageing. Oxygen-free radicals formed during normal aerobic cellular metabolism attack bases in DNA, and 7, 8-dihydro-8-oxoguanine (8-oxoG) is one of the adducts formed. Eukaryotic replicative DNA polymerases replicate DNA containing 8-oxoG by inserting an adenine opposite the lesion; consequently, 8-oxoG is highly mutagenic and causes G:C to T:A transversions. Genetic studies in yeast have indicated a role for mismatch repair in minimizing the incidence of these mutations. In Saccharomyces cerevisiae, deletion of OGG1, encoding a DNA glycosylase that functions in the removal of 8-oxoG when paired with C, causes an increase in the rate of G:C to T:A transversions. The ogg1Delta msh2Delta double mutant displays a higher rate of CAN1S to can1r forward mutations than the ogg1Delta or msh2Delta single mutants, and this enhanced mutagenesis is primarily due to G:C to T:A transversions. The gene RAD30 of S. cerevisiae encodes a DNA polymerase, Poleta, that efficiently replicates DNA containing a cis-syn thymine-thymine (T-T) dimer by inserting two adenines across from the dimer. In humans, mutations in the yeast RAD30 counterpart, POLH, cause the variant form of xeroderma pigmentosum (XP-V), and XP-V individuals suffer from a high incidence of sunlight-induced skin cancers. Here we show that yeast and human POLeta replicate DNA containing 8-oxoG efficiently and accurately by inserting a cytosine across from the lesion and by proficiently extending from this base pair. Consistent with these biochemical studies, a synergistic increase in the rate of spontaneous mutations occurs in the absence of POLeta in the yeast ogg1Delta mutant. Our results suggest an additional role for Poleta in the prevention of internal cancers in humans that would otherwise result from the mutagenic replication of 8-oxoG in DNA.

Microscopic assessment of pronuclear embryos is not definitive

The microscopic classification of embryos, especially unipronuclear embryos, is not very precise. A number of undocumented and unipronuclear embryos were determined to be diploid following karyotyping and fluorescence in situ hybridization (FISH). Accelerated and asynchronous pronuclear dismantling at the time of checking for embryo fertilization accounts for this disparity. Diploid embryos were also observed among tripronuclear embryos. However, not all embryos ascertained as diploid by FISH were karyotypically normal following full karyotype analysis. By taking into account the "background" abnormality rate, the rate of diploid embryo wastage was estimated to be about 40% among undocumented embryos and about 58% in total. A high percentage of misclassification infers an unintended loss of otherwise transferable embryos. Such a discrepancy is particularly important to older women who have fewer embryos. If these are a woman's only embryos, preimplantation genetic diagnosis might be applicable in determining those that are diploid and suitable for transfer. This could potentially reduce the number of wasted embryos and cycles. The present study has also shown that mosaicism is common but it is still unclear whether mosaicism is indicative of embryonic abnormality or is a fairly common phenomenon among healthy embryos. Bipronuclear embryos that present with abnormal or delayed cleavage are often chaotic in their chromosomal constitution. Such embryos should not be transferred.

Percutaneous epididymal sperm aspiration in a man with congenital bilateral absence of the vas deferens undergoing an assisted reproduction program

Surgical retrieval of spermatozoa for in-vitro fertilisation (IVF) programs for severely oligospermic men has been in use for several years now. In the recent 2 to 3 years, clinicians have begun to move towards non-surgical methods of retrieving sperm in certain selected groups of men. Percutaneous epididymal sperm aspiration (PESA) has had good results in terms of number of sperm obtained, as well as the fertilisation and pregnancy rates. The first reported use of such a technique in Singapore is described.

Requirement of yeast SGS1 and SRS2 genes for replication and transcription

The SGS1 gene of the yeast Saccharomyces cerevisiae encodes a DNA helicase with homology to the human Bloom's syndrome gene BLM and the Werner's syndrome gene WRN. The SRS2 gene of yeast also encodes a DNA helicase. Simultaneous deletion of SGS1 and SRS2 is lethal in yeast. Here, using a conditional mutation of SGS1, it is shown that DNA replication and RNA polymerase I transcription are drastically inhibited in the srs2Delta sgs1-ts strain at the restrictive temperature. Thus, SGS1 and SRS2 function in DNA replication and RNA polymerase I transcription. These functions may contribute to the various defects observed in Werner's and Bloom's syndromes.

Effect of dehairing operations on microbiological quality of swine carcasses

To develop a hazard analysis and critical control point plan for food processing operations, critical control points must be determined. Swine slaughtering and dressing operations were investigated to establish their critical control points. We monitored the microbiology of swine carcasses by surface swabbing carcass bellies at various steps during the process and by quantitating total aerobic plate count (APC) and coliforms. Starting with a dehaired carcass, the sequential steps monitored included presingeing, postsingeing, polishing, and chilling. Initial results indicate that singeing and chilling substantially reduced the levels of APC and coliforms, whereas polishing increased their levels. The hygienic characteristics of individual operations involved in dressing swine carcasses were then evaluated in the second experiment. A set of 40 randomly selected carcasses leaving singeer, polisher, shaver, and washer were sampled. Carcasses were heavily contaminated during the final polishing procedure, and the APC increased threefold compared with prepolishing levels. Washing reduced the bacterial numbers by 69%. To reduce the microbial load on swine carcasses, final polishing and manual shaving steps were not used during the dressing operation on a set of 90 carcasses. APCs on singed carcasses were reduced from 1.34 to -0.15 log10 CFU/cm2 when the final polisher and manual shavers were not used. However, carcasses were subsequently recontaminated with bacteria after evisceration, and the APCs were similar (P > 0.05) regardless of whether the final polishing and manual shaving steps were used, averaging 1.30 and 1.46 log10 CFU/cm2. These results indicated that individual operations can be identified as critical control points, appropriate limits can be set and monitored in a hazard analysis and critical control point system, and steps where further changes to reduce bacterial levels may be needed for swine slaughtering plants.

Characterization of mouse peroxiredoxin I genomic DNA and its expression

Peroxiredoxins (Prxs) are a newly defined family of anti-oxidant proteins that have been implicated, via their anti-oxidant activity, in a number of cellular functions, including cell proliferation and differentiation, protection of other proteins from oxidative damage, and intracellular signaling. We isolated genomic DNA sequences of the Prx I genes from the mouse, and characterized their molecular genetic features. Prx I was found to form a small gene family with two and three members; one functional and two pseudogenes. The Prx I-1 gene has splice donor/acceptor site sequences and five or six exons, whereas the Prx I-2 clone has several structural features characteristic of a typical retroposon found to have ORF sequences. We analyzed the expression of pseudogenes, which were not expressed on the transcription levels in the investigated organs. The functional copy of the Prx I-1 gene was expressed abundantly in liver and kidney of the adult, as well as in early developing embryos. This report, together with amino acid/nucleotide sequence similarity between human and mice, provides a basis for speculating on an even earlier event in the evolution of the Prx I gene family, i.e. the Prx I gene was well conserved in human and mice via its anti-oxidant activity.

Organization of HIV-1 pol is critical for Pol polyprotein processing

The HIV pol sequentially encodes protease (PR), reverse transcriptase (RT), and integrase (IN) from the 5'-3' direction. We explored the significance of this gene arrangement. All six possible gene dispositions were examined. In two situations where PR was removed from the leading place and no two genes were in their original location, viral polyprotein processing was abolished. Processing of the polyprotein did not occur when IN was translocated to the front of PR-RT. However, in the following two arrangements, the polyprotein was processed but only at specific sites. First, PR remained in the leading position while the locations of RT and IN were exchanged; viral polyprotein was processed at a site between the upstream transframe peptide (TF) and PR. Second, PR was placed after RT-IN and located at the distal end of Pol. Processing occurred only at the created junction between TF and RT. These results indicated that cleavage after TF occurred autocatalytically but did not proceed to a second site, which needed an extraneous PR for trans-action. Therefore, arranging Pol in the order of PR-RT-IN warrants the streamline processing of the polyprotein once the autocleavage is initiated.

Characterization of the murine gene encoding 1-Cys peroxiredoxin and identification of highly homologous genes

A new type of peroxiredoxin, named 1-Cys peroxiredoxin (1-Cys Prx), reduces hydrogen peroxide with the use of electrons from unidentified electron donor(s). We have isolated the mouse gene encoding 1-Cys Prx (CP-3) and shown that it is comprised of five exons and four introns. Analysis of 5' flanking regions revealed binding sequences of several putative transcription factors such as Sp1, Pit-1a, c-Jun, c-Myc and YY1. It is noticeable that several potential Sp1 binding sites assigned the -60 through -96bp from putative transcription initiation site. The gel shift assays showed that Sp1 and Pit-1a bind specifically to each binding site in 1-Cys Prx promoter. We also isolated two highly related genes such as CP-2 and CP-5. These genes are encoded by single exons, and show 85% of nucleotide sequence homology with the CP-3. The structural features of these genes suggest that they might be intronless genes derived from the CP-3 by the mechanism involving retrotransposition. In addition, our data suggest that they are inserted to a specific site of the mouse L1 repetitive element. The 1-Cys Prx was actively transcribed in a variety of adult tissues as well as in the developing embryos. These results suggest that only the 1-Cys Prx gene might be relevant for studying the function of the 1-Cys Prx in the murine system.

Incidence of hepatocellular carcinoma in transgenic mice expressing the hepatitis B virus X-protein

BACKGROUND/AIMS

Chronic infection with hepatitis B virus is a high-risk factor for hepatocellular carcinoma in humans. The HBV X-protein, a multi-functional viral regulator, has been suspected to play a positive role in hepatocarcinogenesis, as demonstrated by the high incidence of hepatocellular carcinoma in HBx-expressing transgenic mice, although it is still controversial. The aim of this study was to generate transgenic mice expressing the HBV X-gene under authentic promoter control and to test whether the gene products can cause hepatic tumors.

METHODS

Three transgenic mouse lines were generated by microinjecting the X-gene construct into hybrid (C57BL/6 x DBA) eggs. Gene expression was tested by protein and mRNA analyses. During an observation period of 18 months, mice were sacrificed and organs subjected to histologic examinations.

RESULTS

Grossly defined hepatocellular carcinomas reproducibly were observed in mice expressing the X-protein, which were investigated through six generations from the age of 11 to 18 months. Among 14 transgenic mice investigated from the age of 11 to 18 months, 12 were found to have hepatocellular carcinoma, grossly or microscopically. The lesion of the hepatocellular carcinoma disclosed a significant increase in the proliferating cell nuclear antigen in the nuclei.

CONCLUSION

The incidence of hepatocellular carcinoma (86%) in our HBV X transgenic mice may be highly significant, since, except for one case, HBV X-gene transgenic mice produced in other laboratories did not develop liver tumor or any other pathologic phenomena.

Analysis of the sex chromosome constitution of sperm in men with a 47, XYY mosaic karyotype by fluorescence in situ hybridization

OBJECTIVE

To determine the incidence of sex chromosome aneuploidy in the sperm of two men with a 47,XYY/46,XY karyotype.

DESIGN

Case report.

SETTING

Infertility clinic in a teaching hospital.

PATIENT(S)

One patient with near normal semen parameters whose wife had a history of miscarriages and one patient with primary infertility and severe oligoasthenozoospermia.

INTERVENTION(S)

Cytogenetic analysis of peripheral lymphocytes and three-color X/Y/18 fluorescence in situ hybridization analysis of sperm.

MAIN OUTCOME MEASURE(S)

Analysis of sex chromosome disomy and diploidy rates in sperm.

RESULT(S)

Both patients had a 47,XYY/46,XY karyotype. The hyperdiploidy rate of patient 1 was 19% and that of patient 2 was 90%. The incidence of disomy XY was significantly elevated in both patients compared with the controls (0.23% and 1.02%, respectively, versus 0.10%). The incidence of disomy YY (0.44% versus 0.10%) was increased only in patient 2, as was the incidence of disomy 18 (0.49% versus 0.09%) and the rate of diploidy (0.83% versus 0.13%). The rate of 24,XX sperm in both patients was not different from that in the controls.

CONCLUSION(S)

Patients with a 47,XYY mosaic karyotype may be at risk of producing offspring with a hyperdiploid sex constitution. These patients should have their sperm investigated by fluorescence in situ hybridization to determine their particular risks before they undergo intracytoplasmic sperm injection.

Estimates of sperm sex chromosome disomy and diploidy rates in a 47,XXY/46,XY mosaic Klinefelter patient

A 47,XXY/46,XY male was investigated for the incidence of aneuploidy in sperm sex chromosomes using a three-colour X/Y/18 fluorescence in situ hybridisation (FISH) protocol. A total of 1701 sperm nuclei were analysed. The ratio of X-bearing to Y-bearing sperm did not differ from the expected 1:1 ratio although there were more 23,Y sperm than 23,X sperm (844 vs 795). There was a significantly increased proportion of disomy XY and XX sperm compared with normal controls (0.41% vs 0.10%, P < 0.001 and 0.29% vs 0.04%, P < 0.01). However, the incidence of YY sperm was similar to the controls (0.06% vs 0.02%). The diploidy rate was also significantly increased (1.7% vs 0.13%, P < 0.0001), as was disomy 18 (0.71% vs 0.09%) and 25,XXY (0.47% vs 0%). The results support the hypothesis that some 47,XXY cells are able to undergo meiosis and produce mature spermatozoa. Patients with mosaic Klinefelter syndrome with severe oligozoospermia have significantly elevated incidences of disomy XY and XX sperm and may be at a slightly increased risk of producing 47,XXX and 47,XXY offspring. Additionally, they may be at risk of producing offspring with autosomal trisomies. Hence, patients with Klinefelter mosaicism scheduled for intracytoplasmic sperm injection intervention should first undergo FISH analysis of their sperm to determine their risk.