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PubMed1997

Morphocultural variants of Septoria tritici isolates.

This is a morphocultural study under in vitro and in vivo condition on some Septoria tritici variants mainly originated from isolates collected from cultivars bearing Bobwhite 'S' and Kavkaz germplasm. The objective was to show the variability in cultural and morphobiometrical characters of atypical isolates (variants) derived from these germplasms and discuss the relationship with the pathogen's adaptative process. The isolates were grown on potato dextrosa agar and studies with the optical and scanning electron microscope were performed. The thallus behaviour and the vegetative structures were described. It was confirmed that these atypical structures belong the S. tritici thallus. Under in vivo condition the isolates developed typical leaf blotch lesions with normal pycnidia. These contained cylindrical cells or pycnidiospores smaller than spores of the "wild type". Possible reasons for the origin of these variants of S. tritici are considered.

Journal Article↗
PubMed2026

Case Report: Early infantile drug-resistant epilepsy and gastrointestinal dysmotility associated with a de novo GNAO1 variant and a 16p13.11 microdeletion.

BACKGROUND: The GNAO1 gene is located on the long arm of chromosome 16 (16q13) and is associated with Developmental and Epileptic Encephalopathy 17. It encodes a protein involved in regulating various neurotransmitters and neuronal growth and development. The 16p13.11 microdeletion is a genomic deletion in the p13.11 region of the short arm of chromosome 16, previously reported to predispose individuals to neurodevelopmental disorders. These two regions do not overlap on the chromosome, and the 16p13.11 microdeletion does not involve the GNAO1 gene locus. CASE PRESENTATION: We reports a 1-month-old infant presenting with concurrent GNAO1 (p. G203R) gene variation and a 16p13.11 microdeletion. The patient initially presented with recurrent abdominal distension in the neonatal period, which gradually progressed to include focal seizures and intractable epileptic spasms. Interictal EEG showed multifocal discharges and burst-suppression patterns. Brain MRI revealed no abnormalities. A full gastrointestinal series suggested intestinal obstruction and gastro-esophageal reflux. Improved whole-exome sequencing identified: 1) A single nucleotide variantion: GNAO1, NM_020988.3:exon6: c.607G > A (p.Gly203Arg). 2) A copy number variation: A pathogenic 1.453 Mb deletion in the 16p13.11 region. CONCLUSIONS: We describe the developmental trajectory of an infant with overlapping features of gastrointestinal symptoms and drug-resistant epilepsy, carrying a GNAO1 variant and a 16p13.11 microdeletion. This case provides insights into the contribution of both single nucleotide variant and copy number variant to the phenotype.

16p13.11 microdeletion↗
PubMed2000

Toxin gene analysis of a variant strain of Clostridium difficile that causes human clinical disease.

A toxin variant strain of Clostridium difficile was isolated from two patients with C. difficile-associated disease (CDAD), one of whom died from extensive pseudomembranous colitis. This strain, identified by restriction endonuclease analysis (REA) as type CF2, was not detected by an immunoassay for C. difficile toxin A. Culture supernatants of CF2 failed to elicit significant enterotoxic activity in the rabbit ileal loop assay but did produce atypical cytopathic effects in cell culture assay. Southern hybridization, PCR amplification, and DNA sequence analyses were performed on the toxin A (tcdA) and toxin B (tcdB) genes of type CF2 isolate 5340. Type CF2 5340 tcdA exhibited a 1,821-bp truncation, due to three deletions in the 3' end of the gene, and a point mutation in the 5' end of the gene, resulting in a premature stop codon at tcdA position 139. Type CF2 5340 tcdB exhibited multiple nucleotide base substitutions in the 5' end of the gene compared to tcdB of the standard toxigenic strain VPI 10463. Type CF2 5340 toxin gene nucleotide sequences and deduced amino acid sequences showed a strong resemblance to those of the previously described variant C. difficile strain 1470, a strain reported to have reduced pathogenicity and no association with clinical illness in humans. REA of strain 1470 identified this strain as a distinct type (CF1) within the same REA group as the closely related type CF2. A review of our clinical-isolate collection identified five additional patients infected with type CF2, three of whom had documented CDAD. PCR amplification of the 3' end of tcdA demonstrated identical 1. 8-kb deletions in all seven type CF2 isolates. REA type CF2 is a toxin variant strain of C. difficile that retains the ability to cause disease in humans but is not detected in clinical immunoassays for toxin A.

Aged↗
PubMed1995

A citrus exocortis viroid variant from broad bean (Vicia faba L.): infectivity and pathogenesis.

A viroid present in very low titres was isolated from symptomless field broad bean plants. It was identified as a variant of citrus exocortis viroid in the T2, V and C domains. Infection of several hosts resulted in a change in the composition of the viroid population. Serial passage through tomato and back to the host of origin, broad bean, resulted in major changes in replication efficiency, host range and pathogenicity. The unique nucleotide sequence differences identified in the original broad bean variant were not conserved after passage through alternative hosts. The effects of these sequence variations on viroid secondary structure result in nonpathogenic viroid variants which can remain unnoticed in certain plant species but may act as reservoirs of viroid disease.

Base Sequence↗
PubMed2003

Pseudomonas aeruginosa alginate is refractory to Th1 immune response and impedes host immune clearance in a mouse model of acute lung infection.

Pseudomonas aeruginosa is an opportunistic respiratory pathogen that accounts for most of the morbidity and mortality in cystic fibrosis (CF) patients. In CF-affected lungs, the bacteria undergo conversion from a non-mucoid to a non-tractable mucoid phenotype, due to overproduction of alginate. The effect of alginate production on pathogenicity was investigated by using an acute lung infection mouse model that compared a non-mucoid P. aeruginosa strain, PAO1, to its constitutive alginate-overproducing derivative, Alg(+) PAOmucA22, and an alginate-defective strain, Alg(-) PAOalgD. Bacterial suspensions were instilled into the left bronchus and examined 24 and 48 h post-infection. The highest bacterial loads and the most severe lung pathology were observed with strain Alg(-) PAOalgD at 24 h post-infection, which may have been due to an increase in expression of bacterial elastase by the mutant. Significantly lower lung and spleen bacterial loads were found in the two non-mucoid (PAO1 and Alg(-) PAOalgD) groups, compared to the mucoid Alg(+) PAOmucA22 group, between 24 and 48 h post-infection. The positive correlation between lung bacteriology and lung macroscopic pathology in the Alg(+) PAOmucA22 group suggests that alginate production not only impedes pulmonary clearing, but also results in severe lung damage. Positive correlations between IL12 levels and lung macroscopic pathology, and between IL12 and IFN-gamma levels in the Alg(+) PAOmucA22 group, suggested a possible contribution of these pro-inflammatory cytokines to tissue damage. No significant differences were found between the three groups in lung cytokine responses at 24 or 48 h post-infection. However, on comparison within each group at 24 and 48 h post-infection, a significant increase in the pro-inflammatory cytokine IFN-gamma was observed. Higher ratios of IFN-gamma/IL4 and IFN-gamma/IL10, but lower IL10 levels, were also found in all three groups. These results indicate a Th1-predominated immune response in these animals. Such cytokine responses could have aided the clearance of non-mucoid P. aeruginosa, but were not sufficient to alleviate infection by the mucoid variants. Alginate production may promote survival and persistence of this pathogenic micro-organism in the lung.

Acute Disease↗
PubMedDate not supplied

Variant serotypes of infectious bronchitis virus isolated from commercial layer and broiler chickens.

Twenty infectious bronchitis virus (IBV) field isolates obtained from commercial layer and broiler chickens in 1987 and 1988 were serotyped using the virus-neutralization (VN) test. Six different previously unrecognized variant serotypes were identified from a total of seven isolates from layer chickens. Only two isolates, both from Maine, were the same variant serotype. Variant serotypes also were recovered from layer flocks in Illinois and Washington and the province of Ontario, Canada. Two different variants were isolated from the same multi-age layer complex in Connecticut. Only one of 13 broiler chicken isolates was found to be a new variant serotype, that being from birds reared in Delaware. Cross-protection studies in specific-pathogen-free chickens indicated that vaccines containing the Holland, L-1, or Connaught strains of Massachusetts (Mass) combined with Arkansas produced a broader spectrum of immunity against challenge with the layer variants than Mass (Holland) alone or Mass (L-1) + Connecticut. All vaccines tested produced solid immunity (greater than or equal to 80% protection) against the broiler variant virus.

Animals↗
PubMed1990

Alterations in the pathogenicity of one Paracoccidioides brasiliensis isolate do not correlative with its in vitro growth.

The in vitro subcultivation of some microorganisms for long periods causes measurable loss of their pathogenicity, which can be reverted by reisolation from infected hosts. We compared the pathogenicity and the in vitro growth pattern of one P. brasiliensis isolate (Pb 18) in its yeast phase, using the following samples: 1) The original pathogenic Pb 18 (OP). 2) Pb 18 attenuated by continuous in vitro subcultivation (AT). 3) Pb 18 (AT) reisolated from susceptible B10.A mice (RS). 4) Pb 18 (AT) reisolated from resistant A/SN mice (RR). Pathogenicity was evaluated by anatomopathology and mortality of mice infected i.p. with 5 x 10(6) fungi. Median survival times of mice infected with OP ranged from 74 to 117 days during the first 51 months of subculturing; with more cycles of subculturing the median survival time increased, reaching 250 days at the 64th month. This indicated decreasing virulence of OP during this period of subculturing. Survival of mice infected with RS and RR was respectively 112 and 123 days, which is similar to the behavior of the OP variant. The in vitro growth curve profile of RR showed significantly higher numbers of total and viable yeasts than the other studied variant. These results show that: 1) Pb 18 isolate loses its pathogenicity by continuous subcultivation. This phenomenon is reverted by reisolation from mice, independently from their susceptibility to the fungus; 2) the in vitro growth patterns of Pb 18 do not correlate with alterations in pathogenicity but are influenced by the host's environment.

Animals↗
PubMed2025

Fe-S cluster deficiency drives small colony variant formation in persistent infections.

INTRODUCTION: Small colony variants (SCVs) of Staphylococcus aureus (S. aureus) are associated with persistent infections and poor clinical outcomes. The mechanisms driving stable SCV formation remain poorly understood, particularly concerning metabolic adaptations. This study explores the in-host evolutionary dynamics of S. aureus and identifies a novel genetic determinant linked to SCV formation. OBJECTIVES: To investigate the genetic mutations and phenotypic adaptations underlying SCV formation, with a focus on the role of a novel mutation in the sufB gene, which is critical for Fe-S cluster biosynthesis. METHODS: Sequential isolates from a patient with recurrent infections were analyzed using whole-genome sequencing, antimicrobial susceptibility testing, and functional assays. The phylogenetic relationship of the isolates was determined, and specific mutations were identified. Functional assays included aconitase and glutamate synthase activity measurements, ATP level quantification, reactive oxygen species (ROS) production, and biofilm formation assays. In vivo pathogenesis was assessed using a murine catheter infection model. RESULTS: A novel frameshift mutation in sufB was identified, disrupting Fe-S cluster biosynthesis and impairing the TCA cycle and electron transport chain, leading to reduced ATP and ROS production. This metabolic reprogramming promoted stable SCV formation, characterized by slow growth, enhanced tolerance to antibiotics and neutrophil-mediated killing, and persistent inflammation in vivo. Restoration of sufB reversed these phenotypes, confirming its pivotal role in SCV-associated persistence. CONCLUSION: sufB is a novel genetic determinant of stable SCV formation through Fe-S cluster deficiency, driving metabolic shifts that enhance immune evasion and chronic infection. Our findings highlight antibiotic stewardship and suggest potential therapeutic strategies for managing persistent SCV-associated infections.

Staphylococcus aureus↗
PubMedDate not supplied

[Possible types of tick-borne diseases and the predictive role of history data in their diagnosis (parasitological aspects of the problem)].

The paper discusses the proven and probable role of different tick-borne pathogens and their combinations in the occurrence of zoonotic diseases. The variants of coexistence of various combinations of 7 proved disease agents (3 species of Borrelia, 2 species of Ehrlichia, Babesia, and TBE virus) with different, if might to be, disease agents, such as rickettsiae of two groups, which do not belong to the Borrelia burgdorferi sensu lato group spirochetes, are analyzed. The difference of their development and the time of transmission after of the vector Ixodes persulcatus Schulze attachment are considered. Based on the their own hypothesis that one tick specimen is able to be the vector of only three human pathogenic agents simultaneously, the authors examined the possible number of combinations of pathogens, which might be obtained by a patient after 1 tick attachment. Proper history data are recommended as a tool for making a correct diagnosis, wherein the time of attachment has to be a main factor. For example, it should be taken into account that TBE virus might be transmitted only some minutes after attachment by not only a female tick, but also a male one. Mixed infection of virus plus Borrelia might develop only following some hours of attachment (most probably after 18-24 hours). The very similar situation has to be considered to lead to virus-Borrelia-Ehrlichia (or Rickettsia) coinfection. Any combination with Babesia involvement may appear not earlier than 24-36 hours after mixed infected tick attachment (or even later). It is necessary to consider a possible role of apathogenic microorganisms which are present in the most of vector specimens in nature and which might be injected with infected tick saliva may play a possible role in the manifestation of disease and in the prediction of their possible influence.

Animals↗
PubMed2003

Polymorphism of a specific region in gene p23 of Citrus tristeza virus allows discrimination between mild and severe isolates.

The pathogenicity determinants of Citrus tristeza virus (CTV) are presently unknown, although transgenic Mexican limes over-expressing CTV p23, an RNA-binding protein involved in regulating the asymmetrical accumulation of viral RNA strands, display typical CTV symptoms. Here we compared the predominant sequence variants of gene p23 from 18 CTV isolates of different geographic origin and pathogenicity characteristics. Phylogenetic analysis of these sequences revealed three groups of isolates: i) mild, inducing only symptoms in lime and/or decline of citrus species grafted on sour orange rootstock, ii) severe, causing additionally stem pitting on sweet orange and/or grapefruit, and iii) an atypical group of isolates inciting variable symptoms. The sequences of the isolates located at the periphery of each group were recombinants. Pairwise comparisons of the predicted amino acid sequences showed that residues at positions 78-80 were characteristic of each group of isolates. Group-specific primers based on these differences allowed RT-PCR detection of each sequence type in dsRNA-rich preparations from infected tissues. While mild isolates contained only the sequence characteristic of this group, most severe isolates contained the sequences characteristic of their group, and additionally, sequences characteristic of the mild and/or the atypical groups, suggesting that the severe phenotype is associated with the presence of the severe and/or the atypical sequence types. This association can be exploited for quick detection of potentially damaging sequence variants and for monitoring cross protection.

Amino Acid Sequence↗
PubMed2001

A polymorphic variant of the gene coding desmoglein 1, the target autoantigen of pemphigus foliaceus, is associated with the disease.

Two polymorphic markers were identified on the desmoglein 1 gene which encodes the autoantigen targeted by pathogenic antibodies in pemphigus foliaceus (PF), a cutaneous autoimmune blistering disease. The first marker, made of a variant haplotype of five mis-sense mutations located on the part of the gene encoding the fourth and fifth extracellular domains of the protein, is not associated with the disease. The second marker consists of a single silent T to C transition at position 809 and was found to be significantly more frequent (P = 0.015) in Caucasian PF patients (n = 36) than in controls (n = 98). Thus, pemphigus foliaceus constitutes another example of autoimmune disease in which the autoantigen polymorphism contributes to disease susceptibility.

Amino Acid Sequence↗
PubMedDate not supplied

[Attenuated variants of the tick-borne encephalitis virus complex].

The paper presents the results of the study of 8 attenuated strains of viruses of the tick-borne encephalitis complex by the marker of pathogenicity for Syrian hamsters in comparison with virulent virus strains. The group of the attenuated strains was found to be nonhomogeneous in this marker of pathogenicity for Syrian hamsters. One of the 8 strains, Pan-114, proved to be highly virulent for these animals by the intracerebral route. The analysis of the experimental results and data from the literature shows the degree of pathogenicity of attenuated strains to differ for mice, Syrian hamsters and monkeys, apparently indicating that each virus variant is attenuated only for a given species of laboratory animals.

Animals↗
PubMed2002

Complement activation selectively potentiates the pathogenicity of the IgG2b and IgG3 isotypes of a high affinity anti-erythrocyte autoantibody.

By generating four IgG isotype-switch variants of the high affinity 34-3C anti-erythrocyte autoantibody, and comparing them to the IgG variants of the low affinity 4C8 anti-erythrocyte autoantibody that we have previously studied, we evaluated in this study how high affinity binding to erythrocytes influences the pathogenicity of each IgG isotype in relation to the respective contributions of Fcgamma receptor (FcgammaR) and complement. The 34-3C autoantibody opsonizing extensively circulating erythrocytes efficiently activated complement in vivo (IgG2a = IgG2b > IgG3), except for the IgG1 isotype, while the 4C8 IgG autoantibody failed to activate complement. The pathogenicity of the 34-3C autoantibody of IgG2b and IgG3 isotypes was dramatically higher (>200-fold) than that of the corresponding isotypes of the 4C8 antibody. This enhanced activity was highly (IgG2b) or totally (IgG3) dependent on complement. In contrast, erythrocyte-binding affinities only played a minor role in in vivo hemolytic activities of the IgG1 and IgG2a isotypes of 34-3C and 4C8 antibodies, where complement was not or only partially involved, respectively. The remarkably different capacities of four different IgG isotypes of low and high affinity anti-erythrocyte autoantibodies to activate FcgammaR-bearing effector cells and complement in vivo demonstrate the role of autoantibody affinity maturation and of IgG isotype switching in autoantibody-mediated pathology.

Anemia, Hemolytic, Autoimmune↗
PubMed2005

SIVsm quasispecies adaptation to a new simian host.

Despite the potential for infectious agents harbored by other species to become emerging human pathogens, little is known about why some agents establish successful cross-species transmission, while others do not. The simian immunodeficiency viruses (SIVs), certain variants of which gave rise to the human HIV-1 and HIV-2 epidemics, have demonstrated tremendous success in infecting new host species, both simian and human. SIVsm from sooty mangabeys appears to have infected humans on several occasions, and was readily transmitted to nonnatural Asian macaque species, providing animal models of AIDS. Here we describe the first in-depth analysis of the tremendous SIVsm quasispecies sequence variation harbored by individual sooty mangabeys, and how this diverse quasispecies adapts to two different host species-new nonnatural rhesus macaque hosts and natural sooty mangabey hosts. Viral adaptation to rhesus macaques was associated with the immediate amplification of a phylogenetically related subset of envelope (env) variants. These variants contained a shorter variable region 1 loop and lacked two specific glycosylation sites, which may be selected for during acute infection. In contrast, transfer of SIVsm to its natural host did not subject the quasispecies to any significant selective pressures or bottleneck. After 100 d postinfection, variants more closely representative of the source inoculum reemerged in the macaques. This study describes an approach for elucidating how pathogens adapt to new host species, and highlights the particular importance of SIVsm env diversity in enabling cross-species transmission. The replicative advantage of a subset of SIVsm variants in macaques may be related to features of target cells or receptors that are specific to the new host environment, and may involve CD4-independent engagement of a viral coreceptor conserved among primates.

Journal Article↗
PubMed2006

Epstein-Barr viral infection in extranodal lymphoma of the head and neck: correlation with prognosis and response to treatment.

AIMS: To determine the prevalence of Epstein-Barr virus (EBV) infection in primary extranodal lymphoma of the head and neck (PELHN) in immunocompetent patients. PELHN represents 16.18% of all lymphoma diagnosed at the National Cancer Institute, Cairo. Although EBV infection is highly associated with lymphoma in immunocompromised patients, the situation in immunocompetent patients is still unclear. MATERIAL AND METHODS: The study included 50 PELHN (11 cases in the nose and paranasal sinuses, 11 in the nasopharynx, 13 in the tonsils, seven in the oropharynx and eight in the oral cavity), five reactive lymph nodes, 15 normal nasopharyngeal tissue and 25 throat washes of healthy subjects from Egypt. Cases and controls were assessed for the presence of EBV by polymerase chain reaction (PCR) and in situ hybridization techniques, the presence of 30 base pair deletion of the LMP-1 (del-LMP1) gene and for the expression of p53, Ki67, bcl-2 and Bax by immunohistochemistry. This was also correlated with the clinical outcome of patients. RESULTS: EBV was detected in 90% and 70% of the cases using EBER in situ hybridization and PCR, respectively. All cases of nasal type lymphoma were positive for EBV. del-LMP1 gene was detected in 24/35 of EBV+ cases (68.6%), whereas 11 cases had wild-type variant either alone or mixed with del-LMP1. There was a significant difference in the frequency of del-LMP1 between lymphoma and normal tissues. Overexpression of Ki67, p53 and bcl-2 was detected in 78.1%, 62.5% and 20% of cases, whereas loss of Bax was detected in 18% of the cases. Multivariate analysis showed that only p53 overexpression, del-LMP1 variant and advanced disease stage are independent prognostic factors. CONCLUSION: EBV infection is frequent in PELHN in Egypt. Possible pathogenic mechanisms involve deregulation of p53 and enhanced proliferation (as detected by high Ki67 index). The presence of del-LMP1 variants, p53 overexpression and advanced disease stage are poor prognostic factors associated with reduced survival and poor response to therapy.

Adolescent↗
PubMedDate not supplied

Torque teno virus (TTV): current status.

Torque teno virus (TTV), currently classified into the family Circoviridae, genus Anellovirus, was first found in a patient with non-A-E hepatitis. TTV has a single stranded circular DNA of approximately 3.8 kb. TTVs are extraordinarily diverse, spanning five groups including SANBAN and SEN viruses. Torque teno mini virus (TTMV) with approximately 2.9 kb genome also has wide variants. Recently, two related 2.2- and 2.6-kb species joined this community. Recombinations between variants are frequent. This extensive TTV diversity remains unexplained; it is unclear how TTVs could be viable, and why they require such genetic variation. An unequivocal culture system is still not available. TTVs are ubiquitous in > 90% of adults worldwide but no human pathogenicity of TTV has been fully established. Epidemiological surveys need to specify the variants being studied and clinical targets, and must calibrate the sensitivity of the assay used. Potentially interesting observations include a higher viral load in patients with severe idiopathic inflammatory myopathies, cancer and lupus. Active replication was also found in infants with acute respiratory diseases. TTV/TTMV-related viruses were found in chimpanzees, apes, African monkeys and tupaias, and also in chickens, pigs, cows, sheep and dogs. Experimentally, rhesus monkeys were persistently infected by TTV, but only 1/53 chimpanzees. TTV transcribes three species of mRNAs, 3.0-, 1.2- and 1.0-kb in the ratio of 60:5:35. Recently, at least three mRNAs were shown in chicken anaemia virus. The genomic region -154/-76 contains a critical promoter. TTV seems to have at least three proteins; however, the definite functions of these proteins await further research work.

Adult↗
PubMed2005

Increased risk of idiopathic chronic pancreatitis in cystic fibrosis carriers.

Cystic fibrosis (CF) is a recessive disease caused by mutations of the CF transmembrane conductance regulator (CFTR) gene. The risk of idiopathic chronic pancreatitis (ICP) is increased in individuals who have CFTR genotypes containing a CF-causing mutation plus a second pathogenic allele. It is unknown whether the risk of ICP is increased in CF carriers who have one CF-causing mutation plus one normal allele. In this study, 52 sporadic cases of ICP were ascertained through the European Registry of Hereditary Pancreatitis and Familial Pancreatic Cancer. Individuals with pathogenic cationic trypsinogen mutations were excluded. DNA was comprehensively tested for CFTR mutations using a robotically enhanced, multiplexed, and highly redundant form of single-strand conformation polymorphism (SSCP) analysis followed by DNA sequencing. Fifteen subjects had a total of 18 pathogenic CFTR alleles. Eight subjects had common CF-causing mutations. This group included seven CF carriers in whom the second CFTR allele was normal (4.3 times the expected frequency, P=0.0002). Three subjects had compound heterozygotes genotypes containing two pathogenic alleles (31 times the expected frequency, P<0.0001). A variant allele of uncertain significance (p.R75Q) was detected in eight of the 52 ICP subjects and at a similar frequency (13/96) in random donors. ICP differs from other established CFTR-related conditions in that ICP risk is increased in CF carriers who have one documented normal CFTR allele. Having two CFTR mutations imparts a higher relative risk, while having only one mutation imparts a higher attributable risk.

Adult↗
PubMed2004

Prenatal diagnosis of interstitially satellited 6p.

OBJECTIVES: To present the prenatal diagnosis of de novo interstitially satellited 6p and a review of the literature. CASE: An amniocentesis was performed at 18 weeks' gestation because of paternal balanced translocation, t(6;14)(p22;p12). Family history of the father showed the derivative chromosomes to be transmitted through at least two generations with three members affected with partial trisomy 6p (6p22 --> 6pter). RESULTS: Cytogenetic analysis of the cultured amniocytes revealed an interstitial insertion of a nucleolar organizer region (NOR) in 6p22 and a karyotype of 46,XX, rec(6)ins(6;14)t(6;14)(6pter --> 6p22::14p12 -->14p12::6p22 --> 6qter). Level II ultrasound examinations revealed normal findings. The parents opted to terminate the pregnancy. A 650-g fetus was delivered at 23 weeks' gestation without any gross abnormalities. Cytogenetic analysis of the cord blood lymphocytes confirmed the prenatal diagnosis. CONCLUSIONS: The present case provides evidence that a de novo interstitial insertion of a NOR into a nonacrocentric chromosome can be derived from a parental balanced reciprocal translocation involving the satellite stalk region of an acrocentric chromosome. The NOR-inserted chromosome seems to be a harmless variant. However, a de novo interstitial NOR translocation can be pathogenic if there is genomic disruption at the site of translocation, which should be included in genetic counseling and perinatal investigation.

Adolescent↗