Rare deleterious mutations of HNRNP genes result in shared neurodevelopmental disorders

BACKGROUND

With the increasing number of genomic sequencing studies, hundreds of genes have been implicated in neurodevelopmental disorders (NDDs). The rate of gene discovery far outpaces our understanding of genotype-phenotype correlations, with clinical characterization remaining a bottleneck for understanding NDDs. Most disease-associated Mendelian genes are members of gene families, and we hypothesize that those with related molecular function share clinical presentations.

METHODS

We tested our hypothesis by considering gene families that have multiple members with an enrichment of de novo variants among NDDs, as determined by previous meta-analyses. One of these gene families is the heterogeneous nuclear ribonucleoproteins (hnRNPs), which has 33 members, five of which have been recently identified as NDD genes (HNRNPK, HNRNPU, HNRNPH1, HNRNPH2, and HNRNPR) and two of which have significant enrichment in our previous meta-analysis of probands with NDDs (HNRNPU and SYNCRIP). Utilizing protein homology, mutation analyses, gene expression analyses, and phenotypic characterization, we provide evidence for variation in 12 HNRNP genes as candidates for NDDs. Seven are potentially novel while the remaining genes in the family likely do not significantly contribute to NDD risk.

RESULTS

We report 119 new NDD cases (64 de novo variants) through sequencing and international collaborations and combined with published clinical case reports. We consider 235 cases with gene-disruptive single-nucleotide variants or indels and 15 cases with small copy number variants. Three hnRNP-encoding genes reach nominal or exome-wide significance for de novo variant enrichment, while nine are candidates for pathogenic mutations. Comparison of HNRNP gene expression shows a pattern consistent with a role in cerebral cortical development with enriched expression among radial glial progenitors. Clinical assessment of probands (n = 188-221) expands the phenotypes associated with HNRNP rare variants, and phenotypes associated with variation in the HNRNP genes distinguishes them as a subgroup of NDDs.

CONCLUSIONS

Overall, our novel approach of exploiting gene families in NDDs identifies new HNRNP-related disorders, expands the phenotypes of known HNRNP-related disorders, strongly implicates disruption of the hnRNPs as a whole in NDDs, and supports that NDD subtypes likely have shared molecular pathogenesis. To date, this is the first study to identify novel genetic disorders based on the presence of disorders in related genes. We also perform the first phenotypic analyses focusing on related genes. Finally, we show that radial glial expression of these genes is likely critical during neurodevelopment. This is important for diagnostics, as well as developing strategies to best study these genes for the development of therapeutics.

Clinical exome sequencing reveals locus heterogeneity and phenotypic variability of cohesinopathies

PURPOSE

Defects in the cohesin pathway are associated with cohesinopathies, notably Cornelia de Lange syndrome (CdLS). We aimed to delineate pathogenic variants in known and candidate cohesinopathy genes from a clinical exome perspective.

METHODS

We retrospectively studied patients referred for clinical exome sequencing (CES, N = 10,698). Patients with causative variants in novel or recently described cohesinopathy genes were enrolled for phenotypic characterization.

RESULTS

Pathogenic or likely pathogenic single-nucleotide and insertion/deletion variants (SNVs/indels) were identified in established disease genes including NIPBL (N = 5), SMC1A (N = 14), SMC3 (N = 4), RAD21 (N = 2), and HDAC8 (N = 8). The phenotypes in this genetically defined cohort skew towards the mild end of CdLS spectrum as compared with phenotype-driven cohorts. Candidate or recently reported cohesinopathy genes were supported by de novo SNVs/indels in STAG1 (N = 3), STAG2 (N = 5), PDS5A (N = 1), and WAPL (N = 1), and one inherited SNV in PDS5A. We also identified copy-number deletions affecting STAG1 (two de novo, one of unknown inheritance) and STAG2 (one of unknown inheritance). Patients with STAG1 and STAG2 variants presented with overlapping features yet without characteristic facial features of CdLS.

CONCLUSION

CES effectively identified disease-causing alleles at the mild end of the cohensinopathy spectrum and enabled characterization of candidate disease genes.

Cardiac valve prostheses, anticoagulation, and pregnancy

The course of 76 pregnancies is reported in 51 women who became pregnant after replacement of one or more heart valves. Age at conception ranged from 17 to 39 years (mean 25). There have been 71 deliveries and five women are still pregnant at the time of writing. In the 71 pregnancies, oral anticoagulants were given during 53, heparin during five, and no anticoagulants during 13. Fetal complications consisted of 12 spontaneous abortions (eight in pregnancies in which oral anticoagulants were given, three in which heparin was given, and one in which no anticoagulants were given), of 12 premature deliveries with seven stillbirths (three on oral anticoagulants and four without anticoagulants), and there were three neonatal deaths (in all all three instances oral anticoagulants had been given during pregnancy). The maternal complications were as follows. Two women with mitral valve prostheses on heparin had thromboembolic episodes. Four women on oral anticoagulants died and 11 developed haemorrhage or systemic embolism. Two of the deaths were caused by bacterial endocarditis, one was the result of obstruction of a mitral valve prosthesis, and one was due to haemorrhage. One patient developed pulmonary oedema during delivery which rapidly resolved. Seven patients had uterine bleeding after delivery (three of them were on heparin and one was on an antiplatelet agent).

A prospective study of psychotic symptoms in dementia sufferers: psychosis in dementia

Eighty-seven out of a clinical cohort of 124 patients with Diagnostic and Statistical Manual of Mental Disorders (3rd ed., rev.) dementia were followed up at monthly intervals for 1 year. Psychotic symptoms were assessed using the Burns's Symptom Checklist, and cognitive functioning was evaluated with the CAMCOG. The annual incidence rate of psychotic symptoms was 47%, although many of the incident symptoms lasted less than 3 months. Fifty-three percent of patients with psychosis experienced resolution of their symptoms. Patients either experienced brief or persistent psychotic disorders, with few having an intermediary course. Persistent psychosis was significantly associated with a 3-month duration of symptoms at baseline. Neuroleptics did not significantly influence the course of psychotic symptoms.

Prosthetic valve endocarditis. A survey

Fifty eight patients (aged 8-59 years, mean 27) treated for prosthetic valve endocarditis from January 1966 to January 1985 were studied retrospectively by review of case notes. There were 12 cases of early and 46 cases of late prosthetic valve endocarditis. These developed in 28 patients with an isolated aortic valve, in 26 with an isolated mitral valve, and in four with both aortic and mitral prosthetic valves. Streptococci were the most commonly isolated microorganisms, followed by staphylococci, Gram negative bacteria, and fungi. A surgical (34 cases) or a necropsy specimen (10 cases) from 44 cases was examined. Eighty two per cent of the patients had congestive heart failure. Twenty four of the 58 patients were medically treated and 17 died (70% mortality). Combined medical and surgical treatment was used in 34 patients; the main indication for surgery was congestive heart failure. Fourteen patients on combined treatment died (40% mortality). Persistent sepsis and prosthetic valve dehiscence were the most common early and late operative complications. The most important influences on outcome were congestive heart failure, the type of micro-organism, the severity and extent of anatomical lesions, the time of onset of prosthetic valve endocarditis, and the type of treatment. This survey indicates that only patients without congestive heart failure or embolic complications and with sensitive micro-organism should be treated medically. In view of the poor prognosis patients with prosthetic valve endocarditis associated with congestive heart failure, persistent sepsis, and repeat arterial emboli should be treated by early surgical intervention.

Moebius syndrome, peripheral neuropathy and hypogonadotrophic hypogonadism

The association of congenital ophthalmoplegia and facial paresis (Moebius syndrome) with a variety of other developmental somatic defects has been widely recognised. Its co-existence with hypogonadism of hypothalamic/pituitary origin and subclinical peripheral neuropathy has been reported and in this paper we describe the second case of the Moebius syndrome in association with hypogonadotrophic hypogonadism and a progressive peripheral neuropathy of mixed axonal and demyelinating type.

A rare cause of non discal sciatica: schwannoma of the sciatic nerve

Schwannomas are peripheral nerve sheath tumors. Schwannomas arising in the sciatic nerve are considered a rare condition. Their symptomatology usually mimics sciatic pain due to a herniated disc, which can delay the diagnosis. We report the case of a patient with chronic sciatica in whom Magnetic Resonance Imaging (MRI) examination of the right thigh revealed a tumor of the sciatic nerve. Excision of the tumor was easily performed without neural lesioning. Histopathological examination revealed the tumor to be a schwannoma. No neurologic deficit was noted postoperatively which confirms the good prognosis of this tumor.

Closed mitral valvotomy in pregnancy--a study of seven cases

Between 1977 and 1987, seven pregnant women (mean age 28 years) had closed mitral valvotomy through a left lateral thoracotomy during their first (3 cases), second (2 cases) or third (2 cases) trimester. Surgery was necessary either because of acute heart failure with pulmonary edema not responding to medical treatment (4 cases) or to prevent the complications of severe mitral stenosis affecting either the mother or the fetus in three patients with desired pregnancies. There were neither maternal nor fetal deaths. The only complication was bleeding from a low insertion of the placenta identified in the early postoperative period in one patient that required a caesarean section, which produced a normal baby. Six pregnancies continued until term with uneventful delivery and produced normal children. We conclude that closed mitral valvotomy is a simple and a low risk procedure in pregnant women. It prevents complications of severe mitral stenosis occurring in either the mother or the fetus during pregnancy and delivery.

Three novel CYP11B1 mutations in congenital adrenal hyperplasia due to steroid 11Beta-hydroxylase deficiency in a moroccan population

BACKGROUND/AIMS

Steroid 11beta-hydroxylase deficiency (11OHD), the second cause of congenital adrenal hyperplasia (CAH), accounts only for 5% of all CAH. To date, only 51 different mutations have been reported with poor clinical and biological data. Most of them could be considered as private mutations except one, p.R448H, identified especially in Moroccan Jews but also in Caucasian patients. As two other CYP11B1 mutations have a high incidence in Tunisian patients, we report from another Maghreb population the clinical, follow-up and molecular genetics of 5 Moroccan patients with classical 11OHD.

METHODS

Patients belonging to 3 families were recruited on clinical data. The diagnosis was confirmed by 11-deoxycortisol determination. Sequencing of the CYP11B1 gene and molecular modeling were performed.

RESULTS

Clinical, hormonal and follow-up data were consistent with a severe form of 11OHD. Gender reassignment and evolution of hypertension were discussed. Three novel mutations, p.Ala259Asp, p.Gly446Val and IVS5+2T>G were identified. As each patient was homozygous for one mutation, we could deduce from their phenotype and our modeling studies that the p.Gly446Val mutation was more severe than p.Ala259Asp.

CONCLUSION

This study shows a good correlation between phenotype and genotype. Each CYP11B1 mutation is new and private, contrasting with the high incidence of two Tunisian mutations.

Clinical exome sequencing in the diagnosis of pediatric neuromuscular disease

BACKGROUND

The diagnosis of uncommon pediatric neuromuscular disease (NMD) is challenging due to genetic and phenotypic heterogeneity, yet is important to guide treatment, prognosis, and recurrence risk. Patients with diagnostically challenging presentations typically undergo extensive testing with variable molecular diagnostic yield. Given the advancement in next generation sequencing (NGS), we investigated the value of clinical whole exome sequencing (ES) in uncommon pediatric NMD.

METHODS

A retrospective cohort study of 106 pediatric NMD patients with a combination of ES, chromosomal microarray (CMA), and candidate gene testing was completed at a large tertiary referral center.

RESULTS

A molecular diagnosis was achieved in 37/79 (46%) patients with ES, 4/44 (9%) patients with CMA, and 15/74 (20%) patients with candidate gene testing. In 2/79 (3%) patients, a dual molecular diagnosis explaining the neuromuscular disease process was identified. A total of 42 patients (53%) who received ES remained without a molecular diagnosis at the conclusion of the study.

CONCLUSIONS

Due to NGS, molecular diagnostic yield of rare neurological diseases is at an all-time high. We show that ES has a higher diagnostic rate compared to other genetic tests in a complex pediatric neuromuscular disease cohort and should be considered early in the diagnostic journey for select NMD patients with challenging presentations in which a clinical diagnosis is not evident.

Primary hydatid disease of the thigh. A rare location

Primary muscle hydatidosis is very rare, accounting for less than 1% of hydatid cyst locations. Clinical symptoms are insidious and non-specific causing a frequent delay in diagnosis. Intramuscular hydatid disease can cause a variety of diagnostic problems, especially in the absence of typical radiologic findings. We report the observation of an 82-year-old man consulting for inguinal tumefaction with radiological exploration suggestive of hydatid cyst of the adductors muscles. Magnetic resonance imaging (MRI) is helpful in diagnosis, since it reveals a very suggestive aspect and demonstrates the relationship between cysts and adjacent structures. Treatment of muscle echinococcosis is based on surgery, which is curative and incurs a low risk of local relapse.

Valve replacement in children under 15 years with rheumatic heart disease

From 1967 through 1984, single- or double-valve replacement for rheumatic heart disease (RHD) was undertaken in 184 children (aged 4 to 15 years) in Tunis. At the time of operation most patients were in an advanced state of cardiac disability, but most of them were still in sinus rhythm. A total of 222 valves were inserted. The most commonly used replacement valve was the Starr-Edwards caged-ball prosthesis, with 12 hospital deaths (6.5%). There were no hospital deaths among 19 children who had a (glutaraldehyde-treated porcine) xenograft replacement valve; however, a much higher rate of valve failure occurred later, owing to valve calcification (14 of 19 replacements, 11 requiring reoperation). There were 24 episodes of clinical thrombo-embolism in 21 children after insertion of a prosthetic valve, but only one in a child with a xenograft valve. Two thirds of the patients with prosthetic valves were on anticoagulants, but fewer than half of them had effective levels because of low compliance. For the group with prosthetic valves, the 10-year survival rate was 70%.

Pediatric Autoimmune Ocular Myasthenia Gravis: Evaluation of Presentation and Treatment Outcomes in a Large Cohort

BACKGROUND

In autoimmune myasthenia gravis (MG), autoantibodies target the neuromuscular junction. Ocular myasthenia gravis (OMG) is localized, affecting only extraocular and/or levator palpebrae muscles. OMG presents across all ages, varying in presentation, treatment modalities, and outcomes. Recently, there have been advances in MG/OMG treatment; their utilization and effectiveness are an important part of optimal disease management.

METHODS

We completed a retrospective chart review of children aged 18 years or younger with a confirmed diagnosis of OMG presenting from 2002 to 2019.

RESULTS

Forty-two patients were included with mean age at presentation of 8.5 years (2 to 18 years). Twenty-one patients (50%) had positive antibodies; 90% had acetylcholine receptor antibodies. Ten patients developed generalized symptoms with mean time to generalization of 13.6 months. Multiple logistic regression showed that older age of onset was a trend predictive factor (P = 0.054; odds ratio 1.17) for generalized disease. All patients were treated with pyridostigmine. Immunomodulating agents included steroids (15), mycophenolate mofetil (four), and intravenous immunoglobulin (one). Three patients underwent thymectomy. Twenty patients reached minimal manifestation status, and 12 achieved remission. Gender, race, and positive antibody status were not statistically significant predictors for advanced immunosuppressive therapy.

CONCLUSIONS

We summarize one of the largest cohorts of pediatric patients with OMG who have undergone up-to-date diagnostic and therapeutic regimens. The predictors of outcome and treatment pathway for OMG patients suggested by this report may be further elucidated by future prospective studies.

Syndromic approach to sexually transmitted infections in Tunisian women: bacteriological validation

The World Health Organization emphasizes an integrated primary care approach using syndromic management of sexually transmitted infections. The objective of our study was to evaluate the quality of care of the syndromic management of sexually transmitted disease in women in Rabta hospital in Tunisia. Algorithms have been developed for: cervicitis due to Neisseria gonorrhoeae or Chlamydia (algorithm 3a), vaginitis due to Trichomonas vaginalis or Chlamydia trachomatis (algorithm 3b) and vaginitis due to Candida (algorithm 3c). A total of 116 women were enrolled in the study during February 2003 to April 2004. The prevalence of each bacterium was Chlamydia (10%), N. gonorrhoeae (1%), Treponema pallidum (1%), T. vaginalis (5%) and Candida (21%). Algorithm '3a' had a sensitivity of 45%, a specificity of 42% and positive predictive value (PPV) of 11.9%. Algorithm '3b' had a sensitivity of 35.7%, a specificity of 68.9% and PPV of 20.8%. Algorithm '3c' had a sensitivity of 12%, a specificity of 88% and PPV of 33.3%. To improve the sensitivity of the syndromic approach, we suggest improving the quality of history taking.

[BCG multifocal osteomyelitis. A case report]

Multifocal osteomyelitis is a rare complication of the Bacille Calmette-Guerin (BCG) vaccine. It particularly affects immunocompromised children and poses a difficult diagnostic problem. A 6-month-old boy had BCG vaccination postnatally and developed extensive disseminated skeletal osteomyelitis. He was found to have severe combined immunodeficiency. Despite antibiotic therapy and bone marrow grafting, the disease was fatal.

[Role of surgery in subaortic stenosis. Report of 56 cases]

INTRODUCTION

Subaortic stenosis is a rare congenital heart disease defined as a left ventricular outflow tract obstruction. We reviewed our surgical experience in this cardiac disease with particularly attention to the different anatomical types of the obstruction.

PATIENTS AND METHODS

From January 1987 to December 1998, 56 patients with a mean age of 12.4 years underwent surgical treatment of subaortic stenosis in our Institution. The diagnosis included: subaortic membrane in 44 cases, fibromuscular process in seven and tunnel like hypertrophy in five.

RESULTS

There were two hospital deaths (2/56 = 3.5%) and three patients presented postoperative heart block. The first postoperative echocardiographic control showed a mean fall in left ventricleaorta gradient of 78%. In a mean follow-up of 36 months, there were no deaths. All patients periodically controlled, showed an echocardiographic progression of the gradient and it was not related to the different anatomical types of the obstruction. There were no signs of aortic insufficiency progression.

CONCLUSION

We can affirm that the surgical treatment of the subaortic obstruction is simple and safe. The medium and long-term progression toward the recurrence is independent to the anatomical type and justify the need of serial echocardiographic control.

Evaluation of in vitro anticancer potential of pharmacological ethanolic plant extracts Acacia modesta and Opuntia monocantha against liver cancer cells

Abstract Acacia modesta (AM) and Opuntia monocantha (OM) are distributed in Pakistan, Afghanistan and India. Both of these plants have different pharmacological properties. This study was designed to evaluate anticancer potential of Acacia modesta (AM) and Opuntia monocantha (OM). Liver cancer cell line HepG2 was used for assessment of anticancer activity. For the evaluation of anti-proliferative effects, cell viability and cell death in all groups of cells were evaluated via MTT, crystal violet and trypan blue assays. For the evaluation of apoptosis ELISA of p53 performed. Furthermore, LDH assay to find out the ability of malignant cells to metabolize pyruvate to lactate and antioxidant enzymes activity (GSH, CAT and SOD) at the end HPLC was performed to find active compound of AM and OM. Cytotoxicity (MTT), Viability assays (trypan blue, crystal viability, MUSE analysis) showed more dead, less live cells in plant treated groups with increase of concentration. Scratch assay for the anti-migratory effect of these plants showed treated groups have not ability to heal scratch/wound. ELISA of p53 for cellular apoptosis showed more release of p53 in treated groups. Antioxidant assay via glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) showed less anti-oxidative potential in treated cancer groups. LDH assay showed more lactate dehydrogenase release in treated groups compared with untreated. HPLC analysis showed the presence of phytochemicals such as steroids, alkaloids, phenols, flavonoids, saponins, tannins, anthraquinone and amino acids in AM and OM plant extracts. Based on all these findings, it can be concluded that ethanolic extracts of Acacia modesta and Opuntia monocantha have promising anti-cancer potential.

In-silico analysis of interacting pathways through KIM-1 protein interaction in diabetic nephropathy

Background

Human Kidney Injury Molecule-1, also known as HAVCR-1 (Hepatitis A virus cellular receptor 1), belongs to the cell-surface protein of immunoglobulin superfamily involved in the phagocytosis by acting as scavenger receptor epithelial cells. The study focused on pinpointing the mechanisms and genes that interact with KIM-1.

Methods

This in-silico study was done from March 2019 to December 2019. The Enrichment and protein-protein interaction (PPI) network carefully choose proteins. In addition, the diagramed gene data sets were accomplished using FunRich version 3.1.3. It was done to unveil the proteins that may affect the regulation of HAVCR1 or may be regulated by this protein. These genes were then further considered in pathway analysis to discover the dysregulated pathways in diabetic nephropathy. The long list of differentially expressed genes is meaningless without pathway analysis.

Results

Critical pathways that are dysregulated in diabetic nephropathy patients have been identified. These include Immune System (Total = 237, P < 0.05), Innate Immune System (Total = 140, P < 0.05), Cytokine Signaling Immune system (Total = 116, P < 0.05), Adaptive Immune System (Total = 85) and Neutrophil degranulation (Total = 78).

Conclusion

The top 5 genes that are interacting directly with HIVCR1 include CASP3, CCL2, SPP1, B2M, and TIMP1 with degrees 161, 144, 108, 107, and 105 respectively for Immune system pathways (Innate Immune System, Cytokine Signaling Immune system, Adaptive Immune System and Neutrophil degranulation).

Deep clinicopathological phenotyping identifies a previously unrecognized pathogenic EMD splice variant

Exome sequencing (ES) has revolutionized rare disease management, yet only ~25%-30% of patients receive a molecular diagnosis. A limiting factor is the quality of available phenotypic data. Here, we describe how deep clinicopathological phenotyping yielded a molecular diagnosis for a 19-year-old proband with muscular dystrophy and negative clinical ES. Deep phenotypic analysis identified two critical data points: (1) the absence of emerin protein in muscle biopsy and (2) clinical features consistent with Emery-Dreifuss muscular dystrophy. Sequencing data analysis uncovered an ultra-rare, intronic variant in EMD, the gene encoding emerin. The variant, NM_000117.3: c.188-6A > G, is predicted to impact splicing by in silico tools. This case thus illustrates how better integration of clinicopathologic data into ES analysis can enhance diagnostic yield with implications for clinical practice.

[Mitral valve prosthesis without anticoagulant treatment. Apropos of 46 cases]

Out of a total of 90 patients with valvular prosthesis not treated with anti-coagulants, 46 only had a prosthesis in the mitral position. These patients were treated in Professor Ben Ismail's department for an average of 58 months (extreme limits 26 and 116 months). The average age of these patients at the time of the operation was 13.6 years. It is important to note that these patients greatly improved as attested to by the evolution of the functional symptoms, cardiac volume, capillary and pulmonary arterial pressure. 7 patients had a thromboembolism (15.5 per cent or 3 embolisms per 100 patient-years). Three cases were minor or rapidly regressed and out of four major cases, one died. This complication is much more frequent in patients treated with anti-coagulants as is the risk of haemorrhage which is sometimes serious or even mortal. In view of these results, it seems legitimate, in these young patients, especially when they are in sino-astrial rhythm, have a good clinical history and are haemodynamic to forego anti-coagulant treatment which may be dangerous in these undisciplined patients under irregular and unusual treatment.

Potential Role of Growth Hormone in a Pediatric Transient Ischemic Attack

Growth hormone (GH) is often prescribed in pediatric populations with short stature and is associated with several potential adverse events. One underrecognized potential adverse event is its effect on intracerebral vasculature, with concern for its ability to cause cerebrovascular accident. We present a pediatric case of presumed transient ischemic attack in the setting of chronic GH administration for idiopathic short stature syndrome. We propose potential pathogenic mechanisms for intracerebral vessel stenosis. We hope this case becomes a resource for clinicians and other healthcare providers when deciding whether or not to start GH in their young patients.

[Infectious endocarditis surgically-treated in the active phase. Apropos of 46 cases]

The clinical and microbiological characteristics, the surgical indications and procedures, the evolution and the principal prognostic factors were reviewed in 46 cases of infectious endocarditis operated in the active phase. Using this date, the authors try to determine the optimal time for surgery during the acute active phase of infectious endocarditis. The study population comprised 28 men and 18 women aged 7 to 64 years (average age: 30). The patients were selected on strict criteria: positive blood cultures during the 48 hours prior to surgery (29 cases), positive valve or valve prosthesis culture (15 cases), the presence of an active cardiac abscess at surgery (7 cases), the presence of a large number of bacteria on histological examination of the valve (17 cases). The patients were divided into two groups: those with endocarditis of native valves (27 cases) and those with endocarditis on prosthetic valves (19 cases). The preoperative clinical features included all the classical signs of IE but congestive cardiac failure was particularly prevalent (62% of cases). Microbiologically, most cases of native valve endocarditis (67%) were due to sensitive organisms (streptococci) whilst the more virulent organisms (staphylococci, gram-negative bacteria and fungi) were observed in prosthetic valve endocarditis (64% of cases). The commonest surgical indication was haemodynamic deterioration (30 cases). The indications were mixed in 15 cases but only one case was operated for uncontrolled infection alone in this series. The surgical procedure was technically complex in 6 cases. Operative mortality was high (18 cases, 39%). The main cause of death was low cardiac output (13 cases).(ABSTRACT TRUNCATED AT 250 WORDS)