Opposite deletions/duplications of the X chromosome: two novel reciprocal rearrangements

Paralogous sequences on the same chromosome allow refolding of the chromosome into itself and homologous recombination. Recombinant chromosomes have microscopic or submicroscopic rearrangements according to the distance between repeats. Examples are the submicroscopic inversions of factor VIII, of the IDS gene and of the FLN1/emerin region, all resulting from misalignment of inverted repeats, and double recombination. Most of these inversions are of paternal origin possibly because the X chromosome at male meiosis is free to refold into itself for most of its length. We report on two de novo rearrangements of the X chromosome found in four hypogonadic females. Two of them had an X chromosome deleted for most of Xp and duplicated for a portion of Xq and two had the opposite rearrangement (class I and class II rearrangements, respectively). The breakpoints were defined at the level of contiguous YACs. The same Xp 11.23 breakpoint was found in the four cases. That of the long arm coincided in three cases (Xq21.3) and was more proximal in case 4 (Xq21.1). Thus class I rearrangements (cases 1 and 2) are reciprocal to that of case 3, whilst that of case 4 shares only the Xp breakpoint. The abnormal X was paternal in the three cases investigated. Repeated inverted sequences located at the breakpoints of rearrangements are likely to favour the refolding of the paternal X chromosome and the recombination of the repeats. The repeat at the Xp11 may synapse with either that at Xq21.3 or that at Xq21.1. These rearrangements seem to originate as the Xq28 submicroscopic inversions but they are identifiable at the microscopic level and result from a single recombination event.

[Orofaciodigital syndrome--a new variant? Psychiatric, neurologic and neuroradiological findings]

Oral-facial-digital (OFD) syndromes are a heterogeneous group of inherited syndromes that have in common anomalies of the face (median cleft lip), the tongue (bifid or lobulated tongue with harmartomas), and the digits (brachydactyly, polydactyly, syndactyly). Due to more or less subtle clinical features, at least seven causally different entities can be identified: 1) OFDS I; 2) OFDS II (Mohr syndrome); 3) OFDS III; 4) OFDS with tibial anomalies (OFDS IV); 5) OFDS V (Thurston syndrome); 6) OFDS VI (Váradi syndrome); and 7) OFDS VII (Whelan syndrome). The neuro-psychiatric clinical observations and MRI findings of a 40 year old woman with a OFD syndrome are described. The observed findings (leukoaraiosis, epilepsy, major depression) in combination with a proven OFD syndrome possibly reflect a new type of OFD syndrome.

New genetic, pathophysiologic, and therapeutic issues in nystagmus

Nystagmus may have onset in infancy or adulthood. Infantile-onset nystagmus is commonly associated with genetic disease, and recognition of the various genetic and nongenetic diseases in which it may develop has led to the understanding that nystagmus is often a response of the oculomotor system to an early-onset, bilateral abnormality of vision. Adult-onset nystagmus most often develops as a result of nongenetic neurologic disease, and it manifests in a variety of patterns. Genetic studies have allowed further identification of the genes and genetic loci associated with nystagmus, and careful eye-movement recordings in patients with various patterns of nystagmus have further clarified the oculomotor pathophysiology.

Detection of mutations in the COL4A5 gene in over 90% of male patients with X-linked Alport's syndrome by RT-PCR and direct sequencing

X-linked Alport's syndrome is caused by mutations in the COL4A5 gene encoding the type IV collagen alpha5 chain (alpha5[IV]). Polymerase chain reaction-single-str and conformation polymorphism (PCR-SSCP) on genomic DNA has previously been used to screen for mutations in the COL4A5 gene, but this method was relatively insensitive, with mutations detected in less than 50% of patients. Here, we report a systematic analysis of the entire coding region of the COL4A5 gene, using nested reverse-transcription-polymerase chain reaction (RT-PCR) and the direct sequence method using leukocytes. This study examines twenty-two unrelated Japanese patients with X-linked Alport's syndrome showing abnormal expression of alpha5(IV) in the glomerular or epidermal basement membranes. Mutations that were predicted to be pathogenic were identified in 12 of the 13 male patients (92%) and five of the nine female patients (56%). Six patients had missense mutations, four had out-of-frame deletion mutations, three had nonsense mutations, and three had mutations causing exon loss of the transcript. The current study shows that nested RT-PCR and the direct sequence method using leukocytes are highly sensitive and offer a useful approach for systematic gene analysis in patients with X-linked Alport's syndrome.

Severe haemophilia A in a female: a compound heterozygote with nonrandom X-inactivation

We report a case of severe haemophilia A (<1% factor VIII level) in a female resulting from an interesting and improbable combination of events. The patient inherited a factor VIII intron 22 inversion from her carrier mother, as well as a second factor VIII inversion involving intron 22 that arose de novo on her paternally derived X chromosome. In addition, the patient's paternally derived X chromosome had been preferentially inactivated in 95+% of her somatic cells. The patient's mother, who was clinically unaffected, carried an intron 22 inversion as well and also showed nonrandom X-inactivation. The patient's mother had a brother with severe haemophilia A. It is therefore likely that the mother's inversion was on her maternally derived X chromosome. Since she was unaffected, it is likely that her inversion-bearing X was the one that was preferentially inactivated.

[X chromosome dominant hereditary nephritis: characterization by pedigree analysis and simple studies in general practice]

A family with chronic renal disease in the Bernese Oberland (Switzerland) is described. Most family members were directly evaluated by the author. The clinical syndromes identified in different family members are quite variable, reaching from asymptomatic glomerular microhematuria to segmental sclerosing glomerulonephritis with end stage renal failure. Based on the observation of the pedigree over five generations, the disorder appears to be transmitted as an x-chromosomal dominant trait. Together with the ultrastructural diagnosis, the disorder corresponds to an Alport's syndrome Typ IV Atkien.

XX/XY chimerism and freemartinism in a female llama co-twin to a male

A 20-month-old female llama was examined because at the time of mating, the male llama was apparently unable to achieve intromission. The female llama had been born co-twin to a male. On physical examination, the vaginal vestibule appeared to end in a blind pouch, and the uterus, cervix, and ovaries could not be identified during transrectal palpation or ultrasonography. Karyotyping was done, and 43% of blood lymphocytes had 2 X chromosomes, and 57% had 1 X and 1 Y chromosome. All skin fibroblasts had 2 X chromosomes. A diagnosis of freemartinism and XX/XY chimerism was made. Because conception of twins may be more common in llamas than birth of twins, it is possible that freemartinism could develop in singleton females, if, for instance, a male twin was conceived and died after the placentas had anastomosed. More widespread use of karyotyping in llamas with congenital defects of the reproductive tract will help to define the incidence of freemartinism.

Diagnosing genetic anomalies by inspection

Several readily identifiable syndromes that have a genetic basis consist of mental retardation, hyperactivity or other abnormal behaviors, and characteristic physical signs. These disorders are not only an opportunity for clinical diagnosis, but they reflect the neurologic underpinning of intellect and behavior. Moreover, the wide variations in their phenotypes suggests that genetic testing be considered in children with abnormal appearance and mental retardation.

Somatosensory evoked potentials in X-linked recessive bulbospinal neuronopathy: a case demonstration

Clinicopathological findings in X-linked recessive bulbospinal neuronopathy were characterized by loss of myelinated fibers in the fasciculus gracilis and depletion of neurons in the ventral horn throughout the same segments. Clinical profile of this rare motor neuron disease include sign and symptom of lower motor neuron involving bulbar and spinal level with minimal or no sensory deficit. Previous electrodiagnostic findings consist of electrophysiological evidence of anterior horn cell disease and decreased or absent sensory action potentials in the peripheral nerve. The role of somatosensory evoked potential which can uncover the involvement of posterior column has never been probed. We report a 22-year-old man who had a clinical syndrome of X-linked bulbospinal neuronopathy. The peripheral electrodiagnostic studies supported the evidence of prolonged anterior horn cell disease and decreased sensory response. The median SEPs revealed delayed N11-N13 and N13-N20 interpeak latencies representing demyelination in fasciculus gracilis of upper cervical cord. Therefore, the median SEPs, an uninvasive procedure, can be used as a supportive method to identify sensory neuronopathy with posterior column lesion in this syndrome, especially when the patient has no obvious sensory and endocrine symptom.

Complete androgen insensitivity in a 47,XXY patient with uniparental disomy for the X chromosome

We describe a unique patient with complete androgen insensitivity syndrome and a 47,XXY karyotype. Androgen receptor assay using cultured pubic skin fibroblasts showed no androgen-binding capacity. Sequence analysis of the androgen receptor gene demonstrated two nonsense mutations, one in exon D and one in exon E. Microsatellite marker analysis showed that the patient is homozygous for all five Xq loci examined. The results suggest that the long-arms of the two X chromosomes are identical, i.e., uniparental isodisomy at least for Xq, and carry the same mutations in the androgen receptor gene. This explains how complete androgen insensitivity syndrome occurred in this 47,XXY individual.

Random X-inactivation in a girl with duplication Xp11.21-p21.3: report of a patient and review of the literature

We describe a 10-month-old girl with abnormal clinical findings and Xp duplication. She showed poor weight gain and developmental retardation, and had several minor anomalies including pigmentary dysplasia (hypomelanosis of Ito). She had a partial short arm duplication in the paternally derived X chromosome, 46,X,dup(X)(p11. 21p21.3), with the normal and duplicated X chromosomes randomly inactivated. These findings indicate that gross functional imbalance in the cells with an active dup(X) chromosome has caused global developmental defects in the patient, and that functional chromosomal mosaicism with respect to the duplicated Xp region has resulted in pigmentary dysplasia. Literature review of 52 patients with partial X duplications revealed (1) random or skewed but not completely selective X-inactivation in 9 of 45 patients examined for the X-inactivation pattern, independently of the size or location of duplicated segments, (2) apparently normal phenotype in 6 of 9 patients with random or skewed X-inactivation, and (3) an abnormal phenotype in 13 of 35 patients with completely selective inactivation of dup(X) chromosomes.

Pentasomy X and hyper IgE syndrome: co-existence of two distinct genetic disorders

We describe a 10-year-old girl with features of a penta-X syndrome. Cytogenetic analysis revealed a 49,XXXXX karyotype and molecular analysis of X-linked polymorphic markers showed that this aneuploidy arose by successive maternal non disjunctions. Apart from these features the patient has a lifelong history of eczema, recurrent pneumonia, and staphylococcal abscesses. Together with consistently increased serum IgE levels, low antibody responses, and low levels of serum IgA and IgG2, these findings are characteristic for the hyper IgE syndrome. While pentasomy X may be due to sequential non disjunctions in meiosis I and meiosis II in the mother, the underlying pathomechanism in hyper IgE syndrome remains unclear. This case is the first with co-existence of pentasomy X and hyper IgE syndromes.

[Pediatric mono-arthritis as initial manifestation of X-linked agammaglobulinemia (M. Bruton)]

INTRODUCTION

There are different causes for knee joint effusions in children. Rheumatoid diseases and hematogenous septic arthritis are the most important differential diagnoses. It is less known that immunodeficiency syndromes may cause serous monarthritis.

RESULTS

A case of a five years old boy with monarthritis of the knee is presented. Blood assay and specific immunologic analysis revealed a so far unknown X-linked agammaglobulinemia (M. Bruton).

CONCLUSIONS

In case of a monarthritis in children the orthopaedic surgeon or the pediatrician is primarily involved. For differential diagnosis X-linked agammaglobulinemia should be considered as reason for monarthritis, especially, if there are other clues to that disease in the medical history. In the case of agammaglobulinemia effusion and swelling will decrease soon after treatment with intravenous gammaglobulin.

Transmission of a Y chromosomal deletion involving the deleted in azoospermia (DAZ) and chromodomain (CDY1) genes from father to son through intracytoplasmic sperm injection: case report

The transmission of a deleted in azoospermia (DAZ) deletion from a severely oligozoospermic patient to his son following intracytoplasmic sperm injection (ICSI) treatment is reported. The case report highlights the fertilizing capacity of spermatozoa carrying Y chromosome deletions in patients treated with ICSI and stresses the importance of genetic counselling in severe male infertility.

[A case of neonatal 49,XXXXY syndrome]

The authors present the case of 49,XXXXY syndrome diagnosed in neonatal age. During the investigation of ambiguous genitalia was identified sex chromosome anomaly. The authors deal with possible pathogenesis of the syndrome and its clinical symptoms in details. They emphasize the importance of both testosterone substitution with pubertal timing, and early intellectual and social development.

Prenatal ultrasound detection of a congenital epulis in a triple X female fetus: a case report

A case of congenital epulis in a triple X infant, whose intra-oral mass was first detected on a 33-week prenatal ultrasound, is described. Two previous ultrasound studies performed at 21 and 28 weeks' gestation showed normal facial anatomy, suggesting accelerated tumour growth during the third trimester. Genetic amniocentesis also showed the infant to possess a 47, XXX karyotype.

Role of multicolor fluorescence in situ hybridization (FISH) in simultaneous detection of probe sets for chromosome 18, X and Y in uncultured amniotic fluid cells

Major aneuploidies diagnosed prenatally involve the autosomes 13, 18, and 21, and sex chromosomes. Fluorescence in situ hybridization (FISH) allows rapid analysis of chromosome copy number in interphase cells. The purpose of this study was to evaluate the role of multicolor fluorescence in situ hybridization in simultaneous detection of probe sets for chromosome 18, X, and Y in uncultured amniotic fluid cells as a safer alternative method for aneuploidy detection prenatally. Fifty amniotic fluid samples were analyzed by FISH and standard cytogenetics. Mean time to obtain results was three days for fluorescence in situ hybridization and 20 days for karyotype. Fluorescence in situ hybridization was informative in 43 samples (86%), and within this group, two aneuploidies were correctly identified. This evaluation demonstrates that FISH with X, Y, and 18 alpha satellite DNA probes could accurately and rapidly detect aneuploidies involving these chromosomes and could be used in any prenatal clinical laboratory.

Sex chromosome aneuploidies in sperm of 47,XYY men

The sex chromosomal equipment in 26,675 sperm of 47,XYY males was analyzed. A total of 5.78% of the nuclei exhibited sex chromosome hyperhaploidy. Six studies have analyzed the sperm of 10 XYY patients and, although these studies indicated some degree of elimination of the extra Y chromosome during spermatogenesis, a certain percentage of XYY germinal cells may also be able to achieve meiosis and produce sperm with gonosomal disomies. All these studies show an increased incidence of gonosomal aneuploidies in sperm, but there are significant discrepancies concerning the extent of these abnormalities. The global frequencies of sperm with an abnormal number of sex chromosomes ranged from 0.578 to 13.91%, depending on the patients. There are several explanations for these discrepancies: differences attributed to fluorescence in situ hybridization methodology, the use of dual or multicolor FISH, recruitment, interindividual variations, and intraindividual variations. This study reports an additional series obtained from another XYY individual and compares and discusses the data on gonosomal hyperhaploidies in sperm of 47 XYY males using in situ hybridization analyses.

Criminality and antisocial behaviour in unselected men with sex chromosome abnormalities

BACKGROUND

Previous studies on male patients with sex chromosome abnormalities (SCA), namely XYY and XXY, suggest that such patients commit criminal acts more frequently than expected. Most of these studies are affected by ascertainment bias.

METHODS

Using a population-based sample of men with SCA, identified by screening 34380 infants at birth between 1967 and 1979, comparison between 16 XYY men, 13 XXY men and 45 controls were made in terms of frequency of antisocial personality disorder (APD) using the Schedule for Affective Disorders and Schizophrenia lifetime version. Rates of criminal convictions were examined in 17 XYY men, 17 XXY men and 60 controls.

RESULTS

XYY males showed a significantly higher frequency of antisocial behaviour in adolescence and adulthood and of criminal convictions than the controls, but multiple regression analysis showed this to be mediated mainly through lowered intelligence. Property offences constituted the majority of offences in all groups. The XXY men did not show an increased rate of criminal convictions. It is possible that this apparently negative result relates to the relatively small numbers of cases and hence low power of this study.

CONCLUSIONS

The findings of this study carry the advantage of not being affected by ascertainment bias and the disadvantage of having low power. It provides evidence for a slightly increased liability to antisocial behaviour in XYY men.

Early onset of X-linked Emery-Dreifuss muscular dystrophy in a boy with emerin gene deletion

A boy developed contractures of the Achilles tendons at 3 years and of the postcervical muscles at 7 years, although neither contractures of the elbows nor cardiac abnormality were recognized by the age of 9 years. Muscle computed tomography scanning revealed changes characteristic of muscle involvement. Emerin was not detected in the biopsied muscle, and RT-PCR and PCR-based genomic DNA analyses of the emerin gene demonstrated no amplification product in the patient. These results confirmed the diagnosis of X-linked Emery-Dreifuss muscular dystrophy (EDMD), and reinforce the necessity of molecular genetic diagnosis of the membrane protein emerin in younger patients with possible EDMD before appearance of the typical symptoms, to avoid sudden cardiac death.

Advances in Y chromosome mapping

The human Y chromosome has long been recognized as being responsible for sex determination. In fact, it also encodes more than 30 genes and gene families that participate in a variety of cellular functions, including bone development, tooth growth, and spermatogenesis. De-novo deletion of Y chromosome segments that contain spermatogenesis genes occurs frequently, resulting in low sperm production and male infertility. This article reviews our current knowledge of the structure and function of the Y chromosome is reviewed.

Deletion of Y chromosome involving the DAZ (deleted in azoospermia) gene in XX males

The testicular histology and the presence or absence of 32 Y DNA loci was investigated, with a focus on the long arm of Y chromosome (Yq) interval 6, by means of a polymerase chain reaction strategy in 2 XX males. Seminiferous tubules lined by only Sertoli cells and a slight thickening of tubular walls were observed. The men showed an absence of 32 Y DNA loci. These facts suggest that severe spermatogenic impairment is caused by deletions of Yq interval 6 in XX males.

Investigation of a unique male and female sibship with Kallmann's syndrome and 46,XX gonadal dysgenesis with short stature

A sibship is described where the brother and a sister both have Kallmann's syndrome (anosmia and deficiency of gonadotrophin releasing hormone) and the woman also has streak ovaries. Although there are several conditions that may occur with Kallmann's syndrome, there are no known reports of ovarian dysgenesis being associated with this disorder. Cytogenetic analysis showed no rearrangement or major deletions of the chromosomes. Linkage analysis using informative microsatellite markers predicts that a gene other than KAL1 (at Xp22.3) is implicated in the Kallmann's syndrome manifesting concurrently with ovarian dysgenesis found in this family.

Maternally inherited cardiomyopathy: clinical and molecular characterization of a large kindred harboring the A4300G point mutation in mitochondrial deoxyribonucleic acid

OBJECTIVES

The purpose of this study was to describe the clinical and molecular features of a large family with maternally inherited cardiomyopathy (MICM).

BACKGROUND

Recently, several mitochondrial deoxyribonucleic acid (mtDNA) point mutations have been associated with MICM. However, the distinctive clinical and morphologic features of MICM are not fully appreciated. This is partially due to the small size of the reported pedigrees, often lacking detailed clinical and laboratory information.

METHODS

Clinical and genetic analysis of the family was carried out.

RESULTS

Echocardiography showed mostly symmetrical hypertrophic cardiomyopathy in 10 family members. The illness had an unfavorable course. Progressive heart failure occurred in three subjects, who eventually died; one individual underwent heart transplantation. Electrocardiographic or echocardiographic signs of cardiac hypertrophy in the absence of significant clinical complaints were observed in five subjects. Neurologic examination was normal. The mutation was detected in blood from all available subjects. Abundance of mutated molecules ranged between 13% and 100% of total mtDNA genomes. The severity of the disease could not be foreseen by the proportion of mutation in blood.

CONCLUSIONS

This report contributes a better description of the clinical aspects of MICM and provides important clues to distinguish it from hypertrophic cardiomyopathy. We suggest that mtDNA mutations, particularly in the transfer ribonucleic acid for isoleucin, should be systematically searched in patients with MICM. The identification of an underlying maternally inherited mitochondrial DNA defect in familial cases of cardiomyopathy may considerably influence the management and genetic counseling of affected patients.

[X-linked recessive bulbospinal neuronopathy--Kennedy's syndrome]

Kennedy's syndrome is an inherited disease which was probably first described 100 years ago. Although rare, a recent report suggests that the prevalence may show considerable regional differences. A review of 30 different names of the disease is given. Originally, the disorder was regarded as a spinal and bulbar muscular atrophy but it is now obvious that there is severe axonal degeneration, also of the sensory fibres with the pattern of a central-peripheral distal axonal neuropathy. This was also present in the two recognized cases presented here. The sensory symptoms develop slowly and it is suggested that a peripheral sprouting compensates for the loss not only of motor, but also sensory fibres. It is important to distinguish the disease from motor neuron diseases since the progression is slow and the expected life span is normal. The clinical presentation with facial palsy and perioral contraction-fasciculations is pathognomonic. However, demonstration of increased (CAG)n repeat size in the androgen receptor gene is diagnostic. A normal (CAG)n repeat size excludes the diagnosis, since the abnormal expansion is the only mutation associated with the disease. Other types of mutations in the androgen receptor gene lead to a different clinical presentation, testicular feminization.

Psychosocial competence of unselected young adults with sex chromosome abnormalities

Very little is known about the adult adaptation of individuals with sex chromosome abnormalities (SCA) except for a few reports based upon biased samples of clinically identified patients. This first report from the Denver SCA study on the adult psychosocial adaptation of 36 unselected propositi, identified at birth, shows a continuation of mild psychological and social problems. Psychiatric interviews and self-reported information revealed that adaptation is quite variable, with many of the nonmosaic propositi not faring as well as their siblings, but in a few instances exceeding the success of brothers and sisters. Within this group of SCA subjects a subset demonstrated more marked pathology and a tendency to over-rate their social adaptation relative to the psychiatric interviewer, suggesting that the exclusive use of self-report questionnaires may not provide accurate assessment of psychological characteristics in this and other special populations. The full adult SCA behavioral phenotype has not yet been established but is emerging through additional reports from this and other studies of unselected SCA adults.

X-chromosome abnormalities in women with premature ovarian failure

OBJECTIVE

To evaluate the significance of X-chromosome abnormalities identified in a series of women with premature ovarian failure (POF).

STUDY DESIGN

Karyotypes were reviewed for all women referred to our cytogenetic laboratory over a five-year interval with the diagnosis of POF. Thirty women aged less than 40 with unexplained secondary amenorrhea and elevated follicle-stimulating hormone were included.

RESULTS

Of the 30 patients, 26 had a normal karyotype and 4 showed the following X-chromosome abnormalities: 46,Xi(Xq), 45,X/46,XX mosaic, 46,X,der(X)t(X;Y)(q28;q12) mat and 46,X,t(X;5)(q22;q11.2) mat. In the two families with familial translocations, carrier females within each family showed considerable variability in age at onset of menopause.

CONCLUSION

Both familial and nonfamilial X-chromosome abnormalities can be identified in women with POF. Cytogenetic studies should not be limited to those patients with very-early-onset POF.

Risk of gonadoblastoma in female patients with Y chromosome abnormalities and dysgenetic gonads

We report two female patients with gonadal dysgenesis and sex chromosome mosaicism involving the Y chromosome. Conventional karyotyping was supplemented with fluorescent in situ hybridisation techniques in order to confirm the presence of Y chromosomes. One patient is a phenotypic female with karyotype 45,X/46,X,idic(Y)(q11.2). She underwent a laparoscopic gonadectomy at which streak ovaries without evidence of gonadoblastoma were removed. The second patient presented as a virilised female with karyotype 45,X/47,XYY. At laparoscopy, she was found to have mixed gonadal dysgenesis with a gonadoblastoma in situ. We recommend early gonadectomy in female children presenting with gonadal dysgenesis and the presence of a Y chromosome although once the gonadoblastoma locus on Y chromosome gene has been cloned it may be possible to identify those patients who have a low risk of developing gonadoblastoma.

Developmental and genetic disorders in spermatogenesis

The most common cause of male infertility is idiopathic. Fresh insights based on genetic and molecular analysis of the human genome permit classification of formerly unexplained disorders in spermatogenesis. In this article, we review new procedures that expand diagnostic and therapeutic approaches to male infertility. Recombinant DNA technology makes it possible to detect specific chromosomal and/or genetic defects among infertile patients. The identification of genes linked to disorders in spermatogenesis and male sexual differentiation has increased exponentially in the past decade. Genetic defects leading to male factor infertility can now be explained at the molecular level, even though the germ cell profile of infertile patients is too variable to permit classification of the clinical phenotype. Increasing knowledge of genes that direct spermatogenesis provides important new information about the molecular and cellular events involved in human spermatogenesis. Molecular analysis of chromosomes and/or genes of infertile patients offers unique opportunities to uncover the aetiology of genetic disorders in spermatogenesis. Increasing numbers of cases, previously classified as idiopathic, can now be diagnosed to facilitate the treatment of infertile men. Advanced knowledge also poses ethical dilemmas, since children conceived with assisted reproductive technologies such as intracytoplasmic sperm injection (ICSI) are at risk for congenital abnormalities, unbalanced complements of chromosomes and male infertility.

XX-male syndrome bearing the sex-determining region Y

The case of a 25-year-old man who presented for evaluation of infertility is described. The physical examination revealed testicular atrophy without gynecomastia. Repeated seminal analyses showed azoospermia, and serum hormonal levels suggested a state of a hypergonadotropic hypogonadism. Chromosomal analysis demonstrated 46XX. Polymerase chain reaction revealed the existence of a sex-determining region Y. The etiology of this rare sex reversal syndrome is discussed and cases reported in Japan are reviewed.

Asynchronous replication of alleles in genomes carrying an extra autosome

Transcriptional activity of genes appears to be highly related to their replication timing; alleles showing the common biallelic mode of expression replicate highly synchronously, whereas those with a monoallelic mode of expression replicate asynchronously. Here we used FISH to determine the level of synchronisation in replication timing of alleles in amniotic fluid cells derived from normal foetuses and from those with either of the trisomies for autosomes 21, 18 or 13, or for sex chromosomes (47,XXX and 47,XXY). Two pairs of alleles, not associated with the extra chromosome, were studied in subjects with each trisomy and three in normal subjects. In cells derived from normal foetuses and from foetuses with sex chromosome trisomies, each pair of alleles replicated synchronously; yet these very same alleles replicated asynchronously in cells derived from foetuses with trisomy for any of the three autosomes studied. The results suggest that the gross phenotypic abnormalities associated with an extra autosome are brought about not only by over-expression of genes present in three doses, but also by modifications in the expression of genes present in the normal two doses.

Partial Xp duplication due to a translocation t(X;15) in two male and two female patients: a familial case report and review of the literature

A three generation familial translocation (X;15)(p22;p11) is responsible for duplication (X)(pter-->p22) in two male and two female patients. It is present in a balanced state in the mothers and with the derivative chromosome 15 in the children. The Xp segment of the derivative chromosome 15 is separated from the X inactivation center and cannot undergo X inactivation. As a result, there is functional disomy of Xp in the male and female patients that is responsible for mental retardation and other phenotypic findings.

Sex reversal due to Xp disomy by t(X;Y)(p21;q11)

A 20-month-old infant exhibiting psychomotor retardation, dysmorphisms and ambiguous external genitalia was found to have a 46-chromosome karyotype including a normal X chromosome and a marker Y with most of Yq being replaced by an extra Xp21-->pter segment. The paternal karyotype (G and C bands) was 46,XY. The marker Y composition was verified by means of FISH with a chromosome X painting, an alphoid repeat and a DMD probe. Thus, the final diagnosis was 46,X,der(Y)t(X;Y)(p21;q11)de novo.ish der(Y)(wcpX+,DYZ3+,DMD+). The patient's phenotype is consistent with the spectrum documented in 13 patients with similar Xp duplications in whom sex reversal with female or ambiguous genitalia has occurred in spite of an intact Yp or SRY gene. A review of t(X;Y) identifies five distinct exchanges described two or more times: t(X;Y)(p21;q11), t(X;Y)(p22;p11), t(X;Y)(p22;q11-12), t(X;Y) (q22;q12), and t(X;Y)(q28;q12). These translocations probably result from a recombination secondary to DNA homologies within misaligned sex chromosomes in the paternal germline with the derivatives segregating at anaphase I.

Case report of a 22-week fetus with 47,XXX karyotype and multiple lower mesodermal defects

A 22-week stillborn fetus with 47,XXX karyotype had lower mesodermal defects consisting of irregular fusion of the sacral vertebrae, anal agenesis, multicystic dysplasia of a horseshoe kidney, a single umbilical artery, dysplastic ovaries, and uterine hypoplasia. This case provides additional evidence for an association between trisomy X and genitourinary defects including lower mesodermal defects sequence.

Polysomies but not Y chromosome losses have prognostic significance in pTa/pT1 urinary bladder cancer

A disturbed cellular DNA content is of potential diagnostic and prognostic relevance in urinary bladder cancer. To evaluate the prognostic significance of individual chromosomal aberrations in superficial bladder cancer, specimens of 105 tumors (67 pTa, 38 pT1) were examined by fluorescence in situ hybridization (FISH). FISH allows quantitation of chromosomes on a cell by cell level. Centromere probes for the chromosomes Y, 1, and 17 were used. There was a strong association between polysomies of the chromosomes 1 (found in 46% of tumors) and 17 (40% of tumors, P < .0001). Polysomies (1 and 17) were significantly more frequent in pT1 than in pTa tumors (P < .0001 each). In pTa tumors, polysomies of both chromosomes were linked to a high risk of recurrences; polysomy 17 was associated with an increased risk of progression (P < .05 each). There was no significant association between polysomies and an unfavorable prognosis in pT1 carcinomas. Previous studies had suggested a prognostic role of Y losses in bladder cancer. However, Y losses were not linked to recurrences or tumor progression in pTa or pT1 tumors of 67 male patients. These data show that marked genetic differences exist between pTa and pT1 carcinomas. They also indicate that polysomies of different chromosomes may have prognostic relevance in pTa urinary bladder cancer.

True hermaphroditism associated with microphthalmia

A 4-year-old boy with an undescending left testis, penoscrotal hypospadia and bilateral microphthalmia was admitted to our hospital. Chromosome analysis revealed a karyotype of 46, XX del(x)(p2 2,31) and the sex-determining region of the Y chromosome (SRY) was negative. The right testis was located in the scrotum and a left cystic ovary-like gonad, a salpinx and a unicorn uterus were found in the left inguinal canal. Histologically the gonad was an ovotestis in which primordial follicles covered infantile seminiferous tubules. Microphthalmia is observed in some congenital syndromes caused by interstitial deletion of the X chromosome. This case suggested that the short arm of the X chromosome was involved in the differentiation of the gonad. Very closely located follicles and infantile seminiferous tubules indicated that induction of meiosis in the fetus was controlled by the local microenvironment in follicles and seminiferous tubules, and not by the systemic hormonal condition.

X-linked lymphoproliferative disease: pathology and diagnosis

X-linked lymphoproliferative disease (XLP) is a rare familial disorder resulting in selective immunodeficiency to the Epstein-Barr virus (EBV), characterized by uncontrolled proliferation of EBV-infected lymphocytes. Phenotypes of this disease are variable and include fulminant infectious mononucleosis, hypogammaglobulinemia, and malignant lymphoma. In this article, we describe a case of a previously healthy 4-year-old boy with serologic evidence of acute EBV infection who died of fulminant hepatic failure. Histopathological examination of tissue obtained postmortem showed hemophagocytosis and prominent polymorphous infiltrates associated with necrosis in the liver, spleen, and lymph nodes. Semiquantitative polymerase chain reaction (PCR) utilizing primers complementary to the EBV gene LMP2a performed on samples of liver tissue demonstrated approximately 0.6 copies of the EBV gene per cell. Immunohistochemistry demonstrated light chain restriction and PCR studies of the immunoglobulin V-D-J region revealed two strong bands, consistent with a clonal B cell proliferation. Extended family history revealed that the boy's family was followed by the XLP Registry, which was established in 1978 to follow kindreds with XLP. The genetic abnormality associated with XLP has been localized to the Xq25, allowing RFLP analysis to identify female carriers and affected boys.

Low rates of pregnancy termination for prenatally diagnosed Klinefelter syndrome and other sex chromosome polysomies

Over the past 9 years we counseled 55 couples whose unborn child was found to carry a sex chromosome polysomy. We performed a survey of postcounseling parental decisions about continuation or termination of these pregnancies. Of the 55 embryos or fetuses, 23 had the karyotype 47,XXY, 10 had 47,XYY, and 12 had 47,XXX. In addition, there were 10 instances of true mosaicism, i.e. 47,XXY/46,XY (n = 5), 47,XYY/46,XY (n = 2), or 47,XXX/46,XX (n = 3). Mean gestational age (+/-standard deviation) at diagnosis was 18.3+/-3.0 weeks. After comprehensive genetic counseling 48 (87.3%) of these pregnancies were carried to term. In seven cases (12.7%) the parents elected a pregnancy termination. Two of 31 pregnancies (6.5%) primarily ascertained at our center were aborted, whereas amongst the 24 referred cases, 5 couples (20.8%) opted for a termination. The mean gestational age of the terminated pregnancies was 19.7 weeks. The overall termination rate of 12.7% appears low in comparison with literature data. Most reports from other institutions present termination rates between 32 and 66%. The reason for the low rate of induced abortions in our study cohort is not clear. Cultural differences in parental perception of sex chromosomal polysomies may be of importance, and peculiarities of genetic counseling at our institution could also play a role. Although counseling was nondirective, we did put emphasis on providing prospective parents with information from unbiased follow-up studies of children with Klinefelter syndrome and other sex chromosome polysomies.

[Diagnosis and management of patients with sex differentiation disorders: experience at the Unit of Medical Genetics of the University of Zulia, Maracaibo, Venezuela]

Abnormalities of sexual differentiation (ASD) represent a group of entities, heterogeneous in their etiopathogenesis and clinical manifestations. In order to characterize and analyze the epidemiologic, clinical, endocrine and genetic aspects of patients with ASD consulting UGM-LUZ between 1971-1996, the families that had at least one of its members affected were evaluated. Strict diagnostic criteria to each entity were applied. Cytogenetic, hormonal, radiological, echographic and anatomopathological evaluations were done in each patient. From 391 families, 429 patient consulted with ASD. They represent 5.4% of the patient who consulted to UGM-LUZ in the same period. 214 (50%) patients with definitive diagnosis of ASD were identified to fill the established inclusion criteria. The distribution was the following: 139 with anomalies of the sexual chromosomes; 36 with congenital adrenal hyperplasia; 21 with complete androgen insensitivity syndrome; 14 with mixed gonadal dysgenesis; and 4 with true hermaphroditism. 183 (42.7%) patients with male pseudohermaphroditism and 17 (3.9%) with female pseudohermaphroditism were diagnosed as they did not fulfill the established diagnostic criteria. 15 (3.4%) patients presented ASD associated to a polymalformative syndrome. The ASD are very complex entities, they need the participation of an interdisciplinary team for their diagnosis and management process.

Prenatal identification of mos 45,X/46,X,+mar in a normal male baby by cytogenetic and molecular analysis

We report a case of mos 45,X/46,X,+mar, diagnosed prenatally by amniocentesis, whose physical examination, including external and internal organs, along with serum testosterone values were normal five years after delivery. The mosaic karyotype was seen in 146 of 240 cells examined (amniotic fluid cells, 110/65; placental chorionic villi: 5/4; cord blood, 21/81; cultured skin fibroblasts, 10/90) from 386 metaphases, and the marker chromosome appeared as a small non-fluorescent acrocentric chromosome. All autosomes appeared normal, and no normal Y chromosome could be demonstrated. Analysis of 26 Y-chromosome loci by molecular techniques such as PCR, Southern analysis using multiple Y-specific DNA probes, and Hae III restriction endonuclease assessment of male-specific repeated DNA in the heterochromatic region of the Y chromosome, and fluorescence in situ hybridization (FISH), revealed the marker was derived from a Y chromosome including p terminal to q11.23, and paracentric inversion in the remaining Y long arm. The formation of testes can be considered as existence of SRY (sex-determining region of Y) as a testis-determining factor. The present report illustrates the importance of FISH and molecular techniques as a complement to cytogenetic methods for accurate identification and characterization of chromosome rearrangements in prenatal diagnosis.