Primary familial brain calcification linked to deletion of 5' noncoding region of SLC20A2.

OBJECTIVES: Primary familial brain calcification (PFBC) is a rare neurological disease often inherited as a dominant trait. Mutations in four genes (SLC20A2, PDGFB, PDGFRB, and XPR1) have been reported in patients with PFBC. Of these, point mutations or small deletions in SLC20A2 are most common. Thus far, only one large deletion covering entire SLC20A2 and several smaller, exonic deletions of SLC20A2 have been reported. The aim of this study was to identify the causative gene defect in a Finnish PFBC family with three affected patients. MATERIALS AND METHODS: A Finnish family with three PFBC patients and five unaffected subjects was studied. Sanger sequencing was used to exclude mutations in the coding and splice site regions of SLC20A2, PDGFRB, and PDGFB. Whole-exome (WES) and whole-genome sequencing (WGS) were performed to identify the causative mutation. A SNP array was used in segregation analysis. RESULTS: Copy number analysis of the WGS data revealed a heterozygous deletion of ~578 kb on chromosome 8. The deletion removes the 5' UTR region, the noncoding exon 1 and the putative promoter region of SLC20A2 as well as the coding regions of six other genes. CONCLUSIONS: Our results support haploinsufficiency of SLC20A2 as a pathogenetic mechanism in PFBC. Analysis of copy number variations (CNVs) is emerging as a crucial step in the molecular genetic diagnostics of PFBC, and it should not be limited to coding regions, as causative variants may reside in the noncoding parts of known disease-associated genes.

Intrafamilial clinical variability in individuals carrying the CHCHD10 mutation Gly66Val.

OBJECTIVES: Mutations in the CHCHD10 gene, which encodes a mitochondrially targeted protein, have emerged as an important cause of motor neuron disease and frontotemporal lobar degeneration. The aim of this study was to assess the clinical variability in a large family carrying the p.Gly66Val mutation of the CHCHD10 gene. This mutation has recently been reported to cause late-onset spinal muscular atrophy (SMAJ) or sensorimotor axonal Charcot-Marie-Tooth neuropathy (CMT2) in the Finnish population. MATERIALS AND METHODS: Nine affected members of an extended Finnish pedigree were included in the study. Detailed clinical and neurophysiological examinations were performed. The CHCHD10 p.Gly66Val mutation was examined by Sanger sequencing. RESULTS: The heterozygous p.Gly66Val mutation was present in all affected individuals from whom a DNA sample was available. The clinical phenotype varied from proximal sensorimotor neuropathy to spinal muscular atrophy and in one case resembled motor neuron disease ALS at its early stages. The age of onset varied from 30 to 73 years. CONCLUSIONS: Our data demonstrate that even within the same family, the p.Gly66Val variant can cause variable phenotypes ranging from CMT2-type axonal neuropathy to spinal muscular atrophy, which may also present as an ALS-like disease. The spectrum of CHCHD10-related neuromuscular disease has widened rapidly, and we recommend keeping the threshold for genetic testing low particularly when dominant inheritance or mitochondrial pathology is present.

APOE and AGT in the Finnish p.Arg133Cys CADASIL population.

BACKGROUND: CADASIL is an inherited systemic small vessel disease, the affected status of brain vessels leading to subcortical vascular dementia. The defective gene is NOTCH3 in which over 230 different pathogenic mutations have been identified. The clinical course of CADASIL is highly variable even within families. Previous studies have shown that additional genetic factors modify the phenotype. AIMS AND METHODS: Altogether, 134 Finnish CADASIL patients with p.Arg133Cys mutation were analysed for possible associations between the apolipoprotein E (APOE) genotype, angiotensinogen (AGT) p.Met268Thr polymorphism or neutral p.Ala202Ala NOTCH3 polymorphism and earlier first-ever stroke or migraine. RESULTS: We found no association between the APOE genotypes, AGT polymorphism, NOTCH3 polymorphism and earlier first-ever stroke or migraine. CONCLUSIONS: The APOE, AGT and NOTCH3 polymorphism did not modify the onset of strokes or migraine in our CADASIL sample, which is one of the largest mutationally homogenous CADASIL populations published to date. International collaboration, pooled analyses and genomewide approaches are warranted to identify the genetic factors that modify the highly variable CADASIL phenotype.

Auditory-evoked potentials in bispectral index-guided anaesthesia for cardiac surgery.

BACKGROUND AND OBJECTIVE: Midlatency auditory-evoked potentials, as measures of the anaesthetic state, were evaluated at similar levels of bispectral index in cardiac surgical patients maintained with either propofol or isoflurane anaesthesia. METHODS: Twenty-four patients were randomly allocated to anaesthesia with propofol (n = 12) or isoflurane (n = 12). Bispectral index was maintained below 60 during surgery. Auditory-evoked potentials were collected before induction of anaesthesia, 10 min after intubation, 30 min after sternotomy, during cardiopulmonary bypass at the time of cross-clamping of the aorta and during stable mild hypothermia, after de-clamping of the aorta, and after the operation. RESULTS: At the pre-determined time points, bispectral index values showed comparable depth of hypnosis in both groups. The latency of the Nb component of midlatency auditory-evoked potentials was significantly increased in the isoflurane group after intubation (P < 0.001) and that of both the Nb and the Pa components after sternotomy (P < 0.001) compared with the propofol group. No differences between the groups were detected with respect to haemodynamic variables. No patient reported recall of intraoperative events. CONCLUSION: After intubation and surgical stimulation, when bispectral index was at a constant level, there was a difference in the Nb and Pa components of the midlatency auditory-evoked potentials between the two anaesthetic regimens, indicating a distinction in the state of anaesthesia. Our results suggest that the parallel use of these two electrophysiological methods can show differences in the components of anaesthesia between various anaesthesia methods in cardiac surgical patients.

Neurologic symptoms are common during gestation and puerperium in CADASIL.

Based on a structured questionnaire and medical records, the authors found that 12 of 25 mothers with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) with the R133C NOTCH3 mutation had had neurologic symptoms in 17 of their 43 pregnancies, most commonly hemiparesthesia (76%), hemiparesis (36%), aphasia (65%), and visual disorders (47%). In 82% of the patients, the symptoms were the first manifestation of CADASIL. The symptoms were most common during puerperium and in patients older than age 30.

Decreased bone mineral density and content in neurofibromatosis type 1: lowest local values are located in the load-carrying parts of the body.

Neurofibromatosis type 1 (NF1) is a dominantly inherited disease. Skeletal ailments such as short stature, kyphoscoliosis, tibial bowing and pseudarthrosis are common osseous manifestations of NF1. Previously, a correlation with scoliosis and decreased bone mineral density (BMD) of the lumbar spine has been reported in 12 NF1 patients. A total of 35 NF1 patients and 26 healthy controls were included in the present study. Of the participants over 20 years of age (26 NF1 patients and all controls) 14 were male and 12 were female, seven of whom were premenopausal. The controls were matched for age, sex and body mass index (BMI). Physical activity and medical history of NF1 patients were evaluated to screen the fractures and osseous manifestations of the disease and to rule out the factors that effect BMD. BMD and bone mineral content (BMC) were measured with DXA, using a total body program. The present study detected a lowered bone mineral density (p =0.028) and content (p <0.001) in NF1 patients of both sexes. The results of the present study also show that NF1 patients have an increased risk for osteoporosis. Among NF1 patients seven cases of osteoporosis and 13 cases of osteopenia were detected. In controls, one case of osteoporosis and 13 cases of osteopenia were detected. The location of the lowest local BMD was clustered to the load-carrying parts of the body in NF1 patients. Physical activity and the medical history of the NF1 patients did not explain the decreased BMD and BMC. The findings of the present and previous studies suggest that the pathogenesis of the osseous manifestations in NF1 may involve impaired development of the skeletal system and impaired maintenance of bone structure.

The effect of carbon dioxide, respiratory rate and tidal volume on human heart rate variability.

BACKGROUND: Heart rate variability (HRV) has been used for assessment of depth of anesthesia. Alterations in respiratory rate and tidal volume modulate the sympatovagal neural drive to the heart. The changes in PaCO2 that accompany changes in breathing pattern may, through chemoreceptors in the brainstem, independently influence the autonomic control of the heart and modulate HRV. METHODS: We measured the effects of PaCO2, tidal volume and respiratory rate on HRV during spontaneous and mechanical ventilation in 22 healthy volunteers and in 25 mechanically ventilated anesthetized patients. RESULTS: Adding CO2 to the inspiratory gas increased high frequency (HF) and low frequency (LF) components of HRV in awake volunteers both during spontaneous and mechanical ventilation, while this effect of CO2 was abolished in patients during anesthesia. Increase of tidal volume increased HF component of HRV only in volunteers during spontaneous ventilation. On the other hand, when respiratory rate was reduced, the balance of HF and LF power moved toward LF power in all study groups. Breathing frequency altered HRV independent on PaCO2, tidal volume and the level of consciousness. In contrast, the effect of PaCO2 appeared to be related to normal level of consciousness, suggesting that a cortical modulation of the autonomic nervous activity contributes to the effects of PaCO2 on HRV. CONCLUSIONS: PaCO2, tidal volume and respiratory rate should be controlled when HRV power spectrum is measured in conscious patients or volunteers, while in anesthetized patients small changes in end-tidal CO2 or tidal volume do not modulate HRV if respiratory rate remains unchanged.

Molecular analysis of astrocytomas presenting after age 10 in individuals with NF1.

BACKGROUND: Fifteen to 20% of children with neurofibromatosis type 1 (NF1) develop low-grade astrocytomas. Although brain tumors are less common in teenagers and adults with NF1, recent studies have suggested that patients with NF1 are at a significantly increased risk of developing astrocytomas. OBJECTIVE: S: To investigate the genetic basis for astrocytoma development in patients with NF1 beyond the first decade of life. METHODS: The authors performed molecular genetic analyses of 10 NF1-associated astrocytomas representing all World Health Organization (WHO) malignancy grades using fluorescence in situ hybridization, loss of heterozygosity, immunohistochemistry, and direct sequencing. RESULTS: Later-onset NF1-associated astrocytomas, unlike histologically identical sporadic astrocytomas, exhibit NF1 inactivation, supporting a direct association with NF1 rather than a chance occurrence. Furthermore, some of these astrocytomas have homozygous NF1 deletion. In addition, genetic changes observed in high-grade sporadic astrocytomas, including TP53 mutation and CDKN2A/p16 deletion, are also seen in NF1-associated high-grade astrocytomas. CONCLUSIONS: Neurofibromatosis type 1-associated astrocytomas occurring in patients older than 10 years exhibit genetic changes observed in sporadic high-grade astrocytomas. Patients with neurofibromatosis type 1 and germline NF1 deletions may be at risk for developing late-onset astrocytomas.

Gliomas presenting after age 10 in individuals with neurofibromatosis type 1 (NF1).

Children with neurofibromatosis 1 (NF1) often develop low-grade gliomas, but brain tumors are infrequently encountered in adults with NF1. The authors present evidence from two clinical series, one including patients known to have NF1 and another focusing on adults with new onset brain tumors, that suggests an association between NF1 and symptomatic gliomas in older individuals. They also summarize the clinical data on 17 adolescents or adults with NF1 and symptomatic gliomas. The findings suggest that individuals with NF1 are at increased risk of developing gliomas throughout their lives.

Phenotype of a homozygous CADASIL patient in comparison to 9 age-matched heterozygous patients with the same R133C Notch3 mutation.

BACKGROUND AND PURPOSE: CADASIL is an autosomal dominant arteriopathy, characterized by multiple brain infarcts, cognitive decline, and finally dementia, which is caused by mutations in Notch3 gene encoding a Notch3 receptor protein. We describe the clinical, neuropsychological, imaging, genetic, and skin biopsy findings in a CADASIL patient homozygous for the C475T mutation resulting in R133C amino acid substitution, in comparison to 9 age-matched heterozygous patients with the same mutation. METHODS: The patients were examined clinically and neuropsychologically and with MRI and positron emission tomography for assessment of cerebral blood flow. The gene defect was analyzed by sequencing the products of polymerase chain reaction of exons 3 and 4 of the Notch3 gene. Dermal arteries were analyzed electron microscopically. RESULTS: The homozygous patient had his first-ever stroke at age 28 years. This is markedly earlier than the average, but the patient's heterozygous son had his first transient ischemic attack-like episode at the same age and another heterozygous patient had his first-ever stroke when only 2 years older. He was neuropsychologically more severely deteriorated than all but 1 of the heterozygous patients. These 2 patients had the most severe (confluent grade D) white matter MRI changes. Positron emission tomography showed markedly reduced cerebral blood flow. Skin biopsy revealed profuse deposits of granular osmiophilic material. The progression of disease in the homozygous case was, however, slower than in the most severely affected heterozygous patient. CONCLUSIONS: Our homozygous patient's phenotype is within the clinical spectrum of CADASIL, although at its severe end. Thus, CADASIL may follow the classic definition of a dominant disease, according to which the heterozygous and homozygous patients are clinically indistinguishable.

Extensive somatic microsatellite mutations in normal human tissue.

Microsatellite (MS) instability occurs in tumors with DNA mismatch repair (MMR) deficiencies but is typically absent in adjacent normal tissue. However, MS mutations have been observed in normal tissues from rare individuals with congenital MMR deficiencies. Autopsy tissues from a 4-year-old with congenital MMR deficiency (MLH1-/-) were examined for MS mutations. Insertions and deletions were observed in CA-repeat MS loci. Approximately 0.26 to 1.4 mutations per MS locus per cell were estimated to be present in normal heart, lymph node, kidney, and bladder epithelium. These findings illustrate that phenotypically normal MMR-deficient cells commonly accumulate MS mutations. Loss of MMR and the accumulation of some MS mutations may occur early in MMR-deficient tumor progression, even before a gatekeeper mutation.

Cardiovascular malformations and other cardiovascular abnormalities in neurofibromatosis 1.

Although it is well recognized that a peripheral vasculopathy may occur in patients with neurofibromatosis 1 (NF1), it is unclear whether cardiovascular abnormalities are more common. We reviewed the frequency of cardiovascular abnormalities, in particular, cardiovascular malformations (CVMs), among 2322 patients with definite NF1 in the National Neurofibromatosis Foundation International Database from 1991-98. Cardiovascular malformations were reported in 54/2322 (2.3%) of the NF1 patients, only 4 of whom had Watson syndrome or NF1-Noonan syndrome. There was a predominance of Class II "flow" defects [Clark, 1995: Moss and Adams' Heart Disease in Infants, Children, and Adolescents Including the Fetus and Young Adult. p 60-70] (43/54, 80%) among the NF1 patients with CVMs. Pulmonic stenosis, that was present in 25 NF1 patients, and aortic coarctation, that occurred in 5, constitute much larger proportions of all CVMs than expected. Of interest was the paucity of Class I conotruncal defects (2 patients with tetralogy of Fallot), and the absence of atrioventricular canal, anomalous pulmonary venous return, complex single ventricle and laterality defects. Besides the 54 patients with CVMs, there were 27 patients with other cardiac abnormalities (16 with murmur, 5 with mitral valve prolapse, 1 with intracardiac tumor, and 5 with electrocardiogram abnormalities). No patient in this study had hypertrophic cardiomyopathy. There were 16 patients who had a peripheral vascular abnormality without an intracardiac CVM, plus an additional 4 patients among those with a CVM who also had a peripheral vascular abnormality.

Occult neurofibroma and increased S100 protein in the skin of patients with neurofibromatosis type 1: new insight to the etiopathomechanism of neurofibromas.

BACKGROUND: Neurofibromas represent proliferation of the connective tissue cells of peripheral nerves and deposition of collagenous extracellular matrix. There is evidence that the appearance and growth of neurofibromas may be associated with prior or ongoing mechanical trauma in patients with neurofibromatosis type 1 (NF1). OBJECTIVE: To study the histologic characteristics of apparently healthy skin of patients with NF1. DESIGN: The histologic features of healthy-looking skin of patients with NF1 were analyzed. SETTING: University hospital. PATIENTS: Ten patients who fulfilled the criteria for NF1. INTERVENTIONS: Punch biopsy specimens of healthy-looking skin of the forearm from 9 volunteer patients and of the upper eyelid during cosmetic operation from 1 volunteer patient were obtained. MAIN OUTCOME MEASURES: The main outcomes were not predicted, and the hypothesis was formulated during data collection. RESULTS: Apparently unaffected skin of 5 patients with NF1 was studied by routine histologic testing with respect to expression of S100 protein. Unexpectedly, analysis of the samples revealed the presence of a small neurofibroma tumor in one of the samples. The tumor was located in deep dermis around a hair follicle. In addition, neurofibromatous tissue not large enough to be called a tumor was found on the same anatomical location in another patient. In further studies, 10 punch biopsy specimens of apparently healthy skin from patients with NF1 were similarly sectioned and analyzed. No tumors were found in these additional samples. In 4 patients, however, abundant S100 protein-positive cells were located within collagenous extracellular matrix surrounding hair follicles. CONCLUSIONS: The skin of patients with NF1 might be more widely affected than previously thought and occult neurofibromas are not rare.

Conduction defects after coronary artery bypass grafting--a disappearing problem?

BACKGROUND AND AIMS: To evaluate the incidence of conduction defects (CDs) following coronary artery bypass grafting (CABG) in three different patient populations, to assess the etiologic factors associated with CDs, and to find out their effect on immediate postoperative outcome of the patient. MATERIAL AND METHODS: Three patient populations were prospectively studied: cohort A consisted of 180 CABG-patients operated between 1990-91, cohort B of 100 patients operated during the year 1993 and cohort C of 118 patients operated from April 1997 to June 1997. Cold crystalloid cardioplegia was used throughout the study years. In the first cohort A, two separate cavae were cannulated and clamped, venting through the right upper pulmonary vein was used, iced cold saline was used in pericardium, and cardioplegia was given until a myocardial temperature of 10-15 degrees of Celcius was attained. In the two later cohorts, two-stage venous cannula and aortic root venting were used and cardioplegia was given only until the activity of the myocardium stopped. Proximal anastomoses were performed after aortic declamping in cohort A, and during aortic occlusion in the two later cohorts. RESULTS: The incidence of permanent CDs in cohort A was 36%, in cohort B 5% and in cohort C 1%. Permanent atrioventricular (AV-) and left-sided blocks disappeared first. Left main coronary artery stenosis and low myocardial temperatures were associated with CDs. Patients with permanent CDs had more often low cardiac output after the operation, their values of cardiac enzymes were higher, and they had more often postoperative infarction than patients without CDs. CONCLUSIONS: The disappearance of all long lasting AV- and left-sided blocks simultaneously with decreasing plasma levels of cardiac enzymes is evidence that protection of both conduction tissue and myocardium had considerably improved in the two later cohorts. Giving cardioplegia in smaller amounts and more often at the same time when raising the general temperature during perfusion were the main reasons for the disappearance of postoperative CDs.

A prospective, randomized study of goal-oriented hemodynamic therapy in cardiac surgical patients.

UNLABELLED: Organ dysfunction and multiple organ failure are the main causes of prolonged hospital stay after cardiac surgery, which increases resource use and health care costs. Increased levels of oxygen delivery and consumption are associated with improved outcome in different groups of postoperative patients. Cardiac surgical patients are at risk of inadequate perioperative oxygen delivery caused by extracorporeal circulation and limited cardiovascular reserves. The purpose of our study was to test whether increasing oxygen delivery immediately after cardiac surgery would shorten hospital and intensive care unit (ICU) stay. Four hundred three elective cardiac surgical patients were enrolled in the study and randomly assigned to either the control or the protocol group. Goals of the protocol group were to maintain SvO(2) >70% and lactate concentration < or =2.0 mmol/L from admission to the ICU and up to 8 h thereafter. Hemodynamics, oxygen transport data, and organ dysfunctions were recorded. The median hospital stay was shorter in the protocol group (6 vs 7 days, P < 0.05), and patients were discharged faster from the hospital than those in the control group (P < 0.05). Discharge from the ICU was similar between groups (P = 0. 8). Morbidity was less frequent at the time of hospital discharge in the protocol group (1.1% vs 6.1%, P < 0.01). Increasing oxygen delivery to achieve normal SvO(2) values and lactate concentration during the immediate postoperative period after cardiac surgery can shorten the length of hospital stay. IMPLICATIONS: Health care economics has challenged clinicians to reduce costs and improve resource use in cardiac surgery and anesthesia in a patient population increasing in age and in severity of disease. Optimizing cardiovascular function to maintain adequate oxygen delivery during the immediate postoperative period after cardiac surgery can decrease morbidity and reduce length of hospital stay.

Mutations in the tyrosine phosphatase CD45 gene in a child with severe combined immunodeficiency disease.

The hematopoietic-specific transmembrane protein tyrosine phosphatase CD45 functions to regulate Src kinases required for T- and B-cell antigen receptor signal transduction. So far, there have been no reports to our knowledge of a human deficiency in a tyrosine-specific phosphatase. Here, we identified a male patient with a deficiency in CD45 due to a large deletion at one allele and a point mutation at the other. The point mutation resulted in the alteration of intervening sequence 13 donor splice site. The patient presented at 2 months of age with severe combined immunodeficiency disease. The population of peripheral blood T lymphocytes was greatly diminished and unresponsive to mitogen stimulation. Despite normal B-lymphocyte numbers, serum immunoglobulin levels decreased with age. Thus, CD45 deficiency in humans results in T- and B-lymphocyte dysfunction.

New function for NF1 tumor suppressor.

The expression and subcellular localization of neurofibromatosis type 1 tumor suppressor was studied in keratinocytes induced to differentiate by increased Ca2+ concentration of the culture medium. Differentiating keratinocytes became intensely immunoreactive for neurofibromatosis type 1 protein, which was apparently associated with cellular fibrils. Double immunolabeling with antibodies to cytokeratin 14 and neurofibromatosis type 1 protein suggested an association of intermediate type cytoskeleton and neurofibromatosis type 1 protein. The presence of neurofibromatosis type 1 protein in cell preparations treated with cytoskeletal buffer indicated a high affinity interaction between intermediate filaments and neurofibromatosis type 1 protein. Further studies utilizing double immunolabelings revealed that the intense neurofibromatosis type 1 tumor suppressor signal on intermediate filaments was temporally limited to the period in keratinocyte differentiation in which the formation of desmosomes takes place. Keratinocytes were also cultured from nine patients with type 1 neurofibromatosis and were studied with respect to cell morphology, and association of neurofibromatosis type 1 protein with intermediate cytoskeleton. The results showed that keratinocytes cultured from patients with neurofibromatosis type 1 displayed a highly variable cell size and morphology compared to controls. The latter findings represent predicted alterations in a situation where cytoskeletal organization is disturbed. Furthermore, differentiating neurofibromatosis type 1 keratinocytes were characterized by a reduced number of cytokeratin bundles that were decorated neurofibromatosis type 1 protein. The results of this study suggest that neurofibromatosis type 1 tumor suppressor exerts its effects in part by controlling organization of cytoskeleton during the formation of cellular contacts.