Prevalence and Patient Characteristics of Ectodermal Dysplasias in Denmark

Importance

Ectodermal dysplasias constitute a group of rare genetic disorders of the skin and skin appendages with hypodontia, hypotrichosis, and hypohidrosis as cardinal features. There is a lack of population-based research into the epidemiology of ectodermal dysplasias.

Objective

To establish a validated population-based cohort of patients with ectodermal dysplasia in Denmark and to assess the disease prevalence and patient characteristics.

Design, Setting, and Participants

This nationwide cohort study used individual-level registry data recorded across the Danish universal health care system to identify patients with ectodermal dysplasias from January 1, 1995, to August 25, 2021. A 3-level search of the Danish National Patient Registry and the Danish National Child Odontology Registry was conducted to identify patients with diagnosis codes indicative of ectodermal dysplasias; patients registered in the Danish RAREDIS Database, the Danish Database of Genodermatoses, and local databases were also added. The search results underwent diagnosis validation and review of clinical data using medical records. Of 844 patient records suggestive of ectodermal dysplasias, 791 patients (93.7%) had medical records available for review. Positive predictive values of the diagnosis coding were computed, birth prevalence was estimated, and patient characteristics were identified. Data analysis was performed from May 4 to December 22, 2023.

Results

The identified and validated study cohort included 396 patients (median [IQR] age at diagnosis, 13 [4-30] years, 246 females [62.1%]), of whom 319 had confirmed ectodermal dysplasias and 77 were likely cases. The combined positive predictive value (PPV) for ectodermal dysplasia-specific diagnosis codes was 67.0% (95% CI, 62.7%-71.0%). From 1995 to 2011, the estimated minimum birth prevalence per 100 000 live births was 14.5 (95% CI, 12.2-16.7) for all ectodermal dysplasias and 2.8 (95% CI, 1.8-3.8) for X-linked hypohidrotic ectodermal dysplasias. A molecular genetic diagnosis was available for 241 patients (61%), including EDA (n = 100), IKBKG (n = 55), WNT10A (n = 21), TRPS1 (n = 18), EDAR (n = 10), P63 (n = 9), GJB6 (n = 9), PORCN (n = 7), and other rare genetic variants.

Conclusions and Relevance

The findings of this nationwide cohort study indicate that the prevalence of ectodermal dysplasias was lower than previously reported. Furthermore, PPVs of the search algorithms emphasized the importance of diagnosis validation. The establishment of a large nationwide cohort of patients with ectodermal dysplasias, including detailed clinical and molecular data, is a unique resource for future research in ectodermal dysplasias.

Employment, occupation, and income in adults with neurofibromatosis 1 in Denmark: a population- and register-based cohort study

BACKGROUND

Little is known about employment status, occupation, and disposable income in adults with NF1.

METHODS

From the Danish National Patient Registry and database of two national Centers for Rare Diseases, we identified 1469 adults with NF1, who were matched to 11,991 randomly selected population comparisons on sex and birth year and month. Annual information on employment, occupation and disposable income was ascertained from national registries in 1980-2019.

RESULTS

Adults with NF1 had a lower odds ratio (OR) for employment [OR 0.71, 95% confidence interval (CI) 0.61-0.83] and higher OR for health-related unemployment (OR 2.94, 95% CI 2.16-3.96) at age 30 years than population comparisons, which persisted at age 40 and 50 years. Somatic diagnoses were associated with a higher OR for health-related unemployment in adults with NF1 than in the population comparisons. Adults with NF1 had a slightly lower disposable income, with a 14% (0.82-0.89) reduction observed among the youngest birth cohort. Furthermore, adults with NF1 were less likely to be in a high skilled occupation at ages 30, 40 and 50 years.

CONCLUSION

Adults with NF1 have a lower employment rate, which was mainly due to health-related reasons and a slightly lower disposable income than adults without NF1. Thus, anticipation guidance for employment should be part of the management of NF1 families.

Endocrine morbidity in neurofibromatosis 1: a nationwide, register-based cohort study

OBJECTIVE

Previous studies have found that neurofibromatosis 1 (NF1) is associated with an increased risk for endocrine disorders, but no comprehensive overview of the risk for specific endocrine disorders has been published. We assessed endocrine morbidity in individuals with NF1 from information on hospital admissions, surgery for endocrine disorders, and relevant medication.

DESIGN

A nationwide population registry-based cohort study.

METHODS

We identified 2467 individuals with NF1 diagnosed between 1977 and 2013 from the Danish National Patient Register and the RAREDIS database and 20 132 randomly sampled age- and sex-matched population comparisons. Information on endocrine diseases was identified using registrations of discharge diagnoses, surgery, and medication prescriptions. The rates of endocrine disorders in individuals with NF1 were compared with those in the comparison cohort in Cox proportional hazard models.

RESULTS

Individuals with NF1 had a higher rate than the comparison group of any endocrine discharge diagnosis (hazard ratio [HR] 1.72, 95% confidence interval [CI]: 1.58-1.87), endocrine-related surgery (2.03, 1.39-2.96), and prescribed medications (1.32, 1.23-1.42). Increased HRs were observed for diseases and surgical operations of several glands, including pheochromocytoma, and for osteoporosis, and osteoporotic fractures. Decreased rates were observed with drugs for type 2 diabetes. Women with NF1 had higher HRs for surgery of the ovaries, uterus, and sterilization, but lower rates of surgeries of cervix and prescriptions for birth control pills.

CONCLUSIONS

Neurofibromatosis 1 is associated with a variety of endocrine disorders, surgery, and medication related to endocrine disease. Awareness of endocrine morbidity is important in the clinical follow-up of individuals with NF1.

School performance of children with neurofibromatosis 1: a nationwide population-based study

Children with neurofibromatosis 1 (NF1) may have a high burden of somatic disease and cognitive impairments, which can lead to poor academic performance. We evaluated school grades from exams ending mandatory schooling (usually around age 15 or 16 years) of children with NF1 in a population-based registry study using a within-school matched design. The study included 285 children with NF1 and 12,000 NF1-free peers who graduated from the same school and year during 2002-2015. We estimated overall and gender-specific grades by subject and compared the grades of children with NF1 with those of NF1-free peers in linear regression models. We also examined the effect of social and socioeconomic factors (immigration status and parental education, income and civil status) on grades and age at finalizing ninth grade. School grades varied considerably by socioeconomic stratum for all children; however, children with NF1 had lower grades by an average of 11-12% points in all subjects. In the adjusted models, children with NF1 had significantly lower grades than their NF1-free peers, with largest negative differences in grades observed for girls with NF1. Finally, children with NF1 were 0.2 (CI 0.1-0.2) years older than their peers on graduating from ninth grade, but only maternal educational modified the age at graduating. In conclusion, students with NF1 perform more poorly than their peers in all major school subjects. Gender had a strong effect on the association between NF1 and school grades; however, socioeconomic factors had a similar effect on grades for children with NF1 and their peers.

Cohort profile: life with neurofibromatosis 1 - the Danish NF1 cohort

PURPOSE

The Danish neurofibromatosis 1 (NF1) cohort was initiated to study health-related, socioeconomic and psychological consequences of living with the monogenetic disorder NF1 using a nationwide and population-based approach.

PARTICIPANTS

The cohort includes all 2467 individuals in Denmark who were hospitalised with or due to NF1 from 1977 to 2013 or registered in the RAREDIS Database (1995-2013), a national clinical database for rare diseases, or both. A comparison cohort matched to individuals with NF1 on sex and date of birth was identified in the Civil Registration System (n=20 132).

FINDINGS TO DATE

All cohort members were linked to the unique Danish registries to obtain information on hospital contacts, birth outcomes, education and partnership. A questionnaire was completed by 244 of the 629 adult cohort members with NF1 registered in the RAREDIS Database to evaluate the psychosocial and emotional burden. Further, neuropsychological tests were performed on 103 adult cohort members with NF1 and 38 adult population comparisons. To date, six studies have been published. Individuals with NF1 had an increased risk for (1) hospitalisation for disorders affecting all organ systems of the body throughout all decades of life, (2) psychiatric disorders, (3) attaining a short or medium long education and (4) not forming a life partner. Women with NF1 had an increased risk for spontaneous abortions and stillbirths. Finally, adults with NF1 had an impaired quality of life and a high need for professional support for physical, psychological and work-related problems, which was partly associated with disease severity and visibility.

FUTURE PLANS

The cohort will regularly be updated with newly diagnosed patients in the RAREDIS Database as well as with outcome information in the Danish registries. New studies are in progress to assess other medical and socioeconomic dimensions of living with NF1.

Early diagnosis enabling precision medicine treatment in a young boy with PIK3R1-related overgrowth

Mosaic PIK3R1 variants have recently been demonstrated in patients with complex vascular malformations and overgrowth in a syndrome resembling PIK3CA-related overgrowth syndrome (PROS). The PIK3CA-inhibitor, alpelisib, seems to be a promising treatment option for PROS patients. We describe a young boy with overgrowth and a pathogenic mosaic variant in PIK3R1; c.1699A > G, p.(Lys567Glu). He was prenatally suspected of a syndrome on the presence of unusual transient fluctuating subcutaneous edemas and lymphedema of his left shoulder. The pathogenic variant, later found to be causative, was below detection threshold in whole-genome sequencing (WGS) analysis of amniotic fluid. Upon delivery a mosaic pathogenic PIK3R1 variant, was identified by whole-exome sequencing (WES) of a skin biopsy. With no proven treatment options available, and based on the theoretical disease mechanism, alpelisib therapy was initiated at nine months of age. In the first year of treatment growth normalized and the affected vascular and lymphatic tissue regressed. No side effects have been observed. This report underlines the importance of early variant detection in children suspected of having severe mosaic overgrowth, and proves that prenatal diagnosis is possible, enabling prompt treatment. Furthermore, it demonstrates the promising effects of alpelisib in this patient group.

Phenotypic spectrum of the recurrent TRPM3 p.(Val837Met) substitution in seven individuals with global developmental delay and hypotonia

TRPM3 encodes a transient receptor potential cation channel of the melastatin family, expressed in the central nervous system and in peripheral sensory neurons of the dorsal root ganglia. The recurrent substitution in TRPM3: c.2509G>A, p.(Val837Met) has been associated with syndromic intellectual disability and seizures. In this report, we present the clinical and molecular features of seven previously unreported individuals, identified by exome sequencing, with the recurrent p.(Val837Met) variant and global developmental delay. Other shared clinical features included congenital hypotonia, dysmorphic facial features (broad forehead, deep-set eyes, and down turned mouth), exotropia, and musculoskeletal issues (hip dysplasia, hip dislocation, scoliosis). Seizures were observed in two of seven individuals (febrile seizure in one and generalized tonic-clonic seizures with atonic drops in another), and epileptiform activity was observed in an additional two individuals. This report extends the number of affected individuals to 16 who are heterozygous for the de novo recurrent substitution p.(Val837Met). In contrast with the initial report, epilepsy was not a mandatory feature observed in this series. TRPM3 pathogenic variation should be considered in individuals with global developmental delays, moderate-severe intellectual disability with, or without, childhood-onset epilepsy.

Psychiatric disorders in individuals with neurofibromatosis 1 in Denmark: A nationwide register-based cohort study

The aim of this study was to assess the risks of psychiatric disorders in a large cohort of 905 individuals with NF1 and 7614 population comparisons matched on sex and year of birth. The cohort was linked to the Danish Psychiatric Central Research Register to ascertain information on hospital contacts for psychiatric disorders based on the International Classification of Diseases version 8 and 10. The hazard ratio (HR) for a first psychiatric hospital contact was higher in girls (4.19, 95% confidence interval [CI] 1.81-9.69) and boys with NF1 (5.02, 95% CI 3.27-7.69) <7 years of age than in the population comparisons. Both sexes had increased HRs for developmental disorders, including attention deficit/hyperactivity disorders, autism spectrum disorders, and intellectual disabilities in childhood. Females with NF1 had also increased HRs for unipolar depression, other emotional and behavioral disorders, and severe stress reaction and adjustment disorders in early adulthood. The HRs for psychoses, schizophrenia, bipolar disorders, and substance abuse were similar in individuals with NF1 and the population comparisons. Finally, the cumulative incidence of a first hospital contact due to any psychiatric disorder by age 30 years was 35% (95% CI 29-41) in females and 28% (95% CI 19-37) in males with NF1. Thus, screening for psychiatric disorders may be important for early diagnosis and facilitation of appropriate and effective treatment in individuals with NF1.

Fracture Rates and Fracture Risk in Patients With Marfan Syndrome: A Nationwide Register-Based Cohort Study

Marfan syndrome (MFS), a rare genetic disease, has a prevalence of 6.5 in 100,000. Studies show that patients with MFS have reduced areal bone mineral density (BMD) compared with non-MFS individuals. We have previously shown that patients with MFS have reduced volumetric BMD and compromised trabecular and cortical bone microarchitecture. The present study was a registry-based, nationwide, population-based, cohort study using register data, aimed to evaluate fracture risk and fracture rates in MFS. We included 406 (196 women) patients with MFS through the Danish National Patient Register and 40,724 (19,327 women) persons, randomly selected and matched from the Civil Registry System. A total of 21.9% of the MFS and 18.9% of the reference population had experienced at least one fracture from 1995 to 2018. The fracture incidence rate was 27.5 per 1000 person-years in the MFS cohort (highest in young men and old women with MFS), and 20.3 per 1000 person-years in the reference population. The overall incidence rate ratio between the MFS and the reference population was 1.35 (95% confidence interval [CI ] 1.18-1.55) for all fractures. When evaluating the risk of being registered with an osteoporosis diagnosis in the Danish National Patient Register, starting relevant treatment for osteoporosis or experiencing a hip or spine fracture, 10.3% of the MFS cohort and 3.3% of the reference population could be classified as being osteoporotic. The between-group subhazard ratio was 3.97 (95% CI 2.56-6.25). Patients with MFS started treatment with an antiosteoporotic drug at a younger age than the reference population (57 [interquartile range 55-67] versus 71 [63-73]) years. The life expectancy in MFS is increasing, resulting in more patients facing diseases that are related to old age, such as age-related bone loss and increased risk of fractures. Our data suggest that bone health and fracture prevention needs to be part of the standard care for patients with MFS. © 2021 American Society for Bone and Mineral Research (ASBMR).

Pregnancy outcomes in women with neurofibromatosis 1: a Danish population-based cohort study

BACKGROUND

The probability of a pregnancy, live birth, stillbirth and abortion has never been assessed in women with neurofibromatosis 1 (NF1) in a large population-based study.

METHODS

We included 1006 women (15-49 years) registered with NF1 in the Danish National Patient Registry or followed in two national Centers for Rare Diseases and 10 020 women from the Danish population. Information on pregnancy outcomes was ascertained from health registries. Cumulative incidence, mean cumulative count, hazard ratios (HRs) and proportion ratios (PRs) with 95% CIs were calculated.

RESULTS

The cumulative incidence of a first pregnancy at age 50 years was slightly lower in women with NF1 (74%; 95% CI 70 to 77) than in population comparisons (78%; 95% CI 77 to 79). When all pregnancies were included, two pregnancies were expected per woman at age of 50 years, irrespective of a NF1 diagnosis. The hazard of a pregnancy did not differ between women with NF1 (HR 1.03; 95% CI 0.95 to 1.11) and the comparisons after adjustment for somatic and psychiatric disease. The proportion of pregnancies that resulted in a live birth was 63% (783/1252) among women NF1 and 68% (8432/12 465) among the comparisons, yielding a PR of 0.95 (95% CI 0.90 to 1.00). The proportions of stillbirths (PR 2.83; 95% CI 1.63 to 4.93) and spontaneous abortions (PR 1.40; 95% CI 1.09 to 1.79) were increased in women with NF1.

CONCLUSIONS

A similar hazard for pregnancy was observed for women with NF1 and population comparisons after adjustment for potential medical consequences of NF1. However, women with NF1 experienced more spontaneous abortions and stillbirths.

Bone Geometry, Density, and Microarchitecture in the Distal Radius and Tibia in Adults With Marfan Syndrome Assessed by HR-pQCT

Marfan syndrome (MFS) is a hereditary disorder of connective tissue caused by mutations in the fibrillin-1 gene. Studies have shown that patients with MFS have lower bone mass, but little is known about the other constituents of bone strength. We hypothesize that patients with MFS will have larger bone area and compromised cortical microarchitecture compared with non-MFS individuals. A total of 74 adult patients with MFS and 145 age- and sex-matched non-MFS reference individuals were included in this study. High-resolution peripheral quantitative computed tomography (HR-pQCT) at the distal radius and distal tibia and dual-energy X-ray absorptiometry of total hip and the lumbar spine were performed, and bone turnover and sex hormones were measured. Patients with MFS had significantly lower areal bone mineral density (BMD) at the total spine (-13%) and total hip (-7%) when compared with the reference group. Patients with MFS had significantly larger total bone area at both the radius (+27%) and tibia (+34%). Volumetric BMD at both measured sites showed significantly reduced total, trabecular, and cortical volumetric BMD in patients with MFS compared with the reference group. The microarchitectural parameters at the radius and tibia were compromised in patients with MFS with significantly reduced trabecular number and thickness, leading to a higher trabecular separation and significantly reduced cortical thickness and increased cortical porosity compared with the reference group. The differences in bone density, geometry, or microarchitecture were not explained by increased bone turnover markers or circulating levels of sex hormones. We conclude patients with MFS have altered bone geometry, altered bone microstructure, and lower bone mass (lower areal BMD and volumetric BMD at all sites) compared with healthy reference individuals. Future studies should focus on fracture rates and fracture risk in adult and aging patients with MFS. © 2020 American Society for Bone and Mineral Research (ASBMR).

Expanding the cerebrovascular phenotype of the p.R258H variant in ACTA2 related hereditary thoracic aortic disease (HTAD)

Heterozygous variants in smooth muscle alpha-actin gene (ACTA2) are the most frequent cause of autosomal dominant hereditary thoracic aortic disease (HTAD). Several genotype-phenotype associations have been described, including a severe multisystemic smooth muscle disorder associated with de novo ACTA2 p.R179 variants, characterized by highly penetrant and early onset vascular disease, involvement of smooth muscle cell (SMC)-dependent organs and a distinct cerebrovascular phenotype. Missense variants at position 258 (p.R258C and p.R258H) have also been reported to have a more severe presentation including an increased risk for aortic dissection and a high risk of stroke. It has previously been suggested that the cerebrovascular phenotype of patients with p.R258 variants could represent a mild presentation of the cerebrovascular phenotype associated with p.R179 variants. Here we report on a five generation HTAD family with the p.R258H variant and describe the cerebrovascular findings seen in three family members, to expand on the previously reported phenotype associated with variants at this codon.

Validity of First-Time Diagnoses of Inherited Ichthyosis in the Danish National Patient Registry and the Danish Pathology Registry

Purpose

Inherited ichthyosis is a monogenetic disease characterized by hyperkeratosis and scaling of the skin, with large interindividual variation in severity. It can affect quality of life for patients and their families. Population-based data on inherited ichthyosis are lacking, which hampers studies into its epidemiology.

Patients and Methods

Based on medical record review, we validated diagnoses of inherited ichthyosis in two nationwide population-based registries commonly used for epidemiological research: The Danish National Patient Registry and the Danish Pathology Registry. The study period was January 1, 1977, through December 31, 2015. Validation samples were taken from one regional hospital without a specialized dermatological department and two specialized dermatological departments. Positive predictive values (PPVs) were estimated overall and for each coding system (ICD-8, ICD-10 and SNOMED), including for specific ICD-10 codes.

Results

We identified 1772 first-time diagnoses of inherited ichthyosis; 363 patients were diagnosed at the departments selected for validation, and 307 of these patients (84.6%) had medical records enabling validation. We observed an overall PPV of 73.3% (95% CI: 68.1-77.9). For ICD-8, ICD-10, and SNOMED diagnoses, the PPVs were 73.2% (95% CI: 58.1-84.3), 74.7% (95% CI: 69.0-79.7), and 46.2% (95% CI: 22.1-71.7), respectively. In analyses for ICD-10 diagnoses, we observed much higher validity of diagnoses from the specialized departments (PPV 79.7%; 95% CI: 74.1-84.3) than the regional hospital (PPV 5.9%; 95% CI: 0.6-24.3). The PPVs for specific diagnoses were 80.1% for ichthyosis vulgaris and 96.6% for X-linked ichthyosis but below 45% for remaining, rarer, subtypes.

Conclusion

The PPV of first-time diagnosis of inherited ichthyosis made at specialized dermatological departments in the Danish National Patient Registry is approximately 80%. Diagnoses from the Danish Pathology Registry had low PPVs precluding their use for research.

Clinical characteristics and quality of life, depression, and anxiety in adults with neurofibromatosis type 1: A nationwide study

Neurofibromatosis type 1 (NF1) is a genetic condition characterized by numerous somatic manifestations. The psychosocial burden in adults has rarely been studied. We examined the prevalence of self-reported impairment of quality of life (QoL), symptoms of anxiety and depression and need for support, associated with disease severity and visibility. We conducted a nationwide cross-sectional study of all 467 adults with NF1 diagnosed between 1977 and 2016 at one of the two national centers for rare diseases in Denmark. A total of 244 (56% response rate) completed a questionnaire that included standard measures of QoL, symptoms of depression and anxiety, indicators of disease-related severity, visibility, and need for professional support. Associations between disease severity and visibility and psychosocial burden were analyzed in descriptive and multivariate models. We observed impaired QoL (mean = 81.3; 95% CI, 76.2; 86.4); 19% reported symptoms of depression (mean = 5.7; SD = 5.4), and 15% reported anxiety (mean = 5.1; SD = 5.2) at a clinical level. Adults with NF1 also reported requiring professional support for physical, psychological, and work-related problems. Disease severity and (partly) visibility were significantly (p < .0001) associated with psychosocial well-being and a requirement for support. This study provides new understanding of the factors associated with impaired QoL, indicating that follow-up care should be optimized into adult life.

The CHD4-related syndrome: a comprehensive investigation of the clinical spectrum, genotype-phenotype correlations, and molecular basis

PURPOSE

Sifrim-Hitz-Weiss syndrome (SIHIWES) is a recently described multisystemic neurodevelopmental disorder caused by de novo variants inCHD4. In this study, we investigated the clinical spectrum of the disorder, genotype-phenotype correlations, and the effect of different missense variants on CHD4 function.

METHODS

We collected clinical and molecular data from 32 individuals with mostly de novo variants in CHD4, identified through next-generation sequencing. We performed adenosine triphosphate (ATP) hydrolysis and nucleosome remodeling assays on variants from five different CHD4 domains.

RESULTS

The majority of participants had global developmental delay, mild to moderate intellectual disability, brain anomalies, congenital heart defects, and dysmorphic features. Macrocephaly was a frequent but not universal finding. Additional common abnormalities included hypogonadism in males, skeletal and limb anomalies, hearing impairment, and ophthalmic abnormalities. The majority of variants were nontruncating and affected the SNF2-like region of the protein. We did not identify genotype-phenotype correlations based on the type or location of variants. Alterations in ATP hydrolysis and chromatin remodeling activities were observed in variants from different domains.

CONCLUSION

The CHD4-related syndrome is a multisystemic neurodevelopmental disorder. Missense substitutions in different protein domains alter CHD4 function in a variant-specific manner, but result in a similar phenotype in humans.

Educational delay and attainment in persons with neurofibromatosis 1 in Denmark

Most research on psychosocial consequences of neurofibromatosis type 1 (NF1) has focused on the relationship between disease factors and cognitive functioning. NF1 may impair domains of learning and attention, resulting in low academic performance. This study is the first nationwide population-based cohort study to investigate educational attainment and delay in completing mandatory school by persons with NF1. Educational information was collected from 550 persons at the age of 30 (born 1965-1984). They were diagnosed with NF1 in Denmark and compared to a cohort of NF1-free persons matched on gender and age (n = 4295). Multinomial logistic models were applied to estimate odds ratios (ORs) for obtaining short (≤9 years) or medium (10-12 years) education compared to long education (>12 years) by the age of 30 years. We calculated the probability of graduating 9^th year of mandatory school at different ages in 932 persons with NF1 and 7962 NF1-free persons (born 1965-2000) using quantile regression. The OR of educational completion for short- and medium-term education was three fold (95% CI 2.55-3.99) and 1.29 fold (95% CI 0.99-1.69) higher, respectively, for persons with NF1 than NF1-free persons after adjusting for birth year, gender, psychiatric and somatic morbidity and mother's education. Persons with NF1 were significantly delayed in graduating mandatory school education compared to NF1-free persons. When 90% of persons have graduated, persons with NF1 were 1.2 times older than the NF1-free persons. Experiencing delays in mandatory school likely affect further educational achievements and may impair employment and entering work force.

Causes of Mortality in the Marfan Syndrome(from a Nationwide Register Study)

The Marfan syndrome (MFS) is strongly associated with aortic disease causing a high prevalence of prophylactic aortic surgery, aortic dissection, and sudden death. The aim of the present study was to evaluate mortality in a nationwide Danish MFS population diagnosed by the Ghent II criteria. In a register-based setting, we identified all Danish patients with MFS (n = 412, men n = 215) by assessment of their medical records. We established a gender and age matched control cohort based on 41,000 control patients (men n = 21,500). MFS cases risk time was 6,669 patient years. We applied Cox regression using each case and his/her control as one stratum, adjusting for age and calendar time. We found a significantly decreased lifespan of 50years compared with 60years among controls. The mortality hazard ratio among MFS compared with controls was significantly increased to3.6 (CI 2.8-4.7, p < 0.001); men 4.0 (CI 2.8-5.7, p < 0.001); women 3.2 (CI 2.1-4.8,p < 0.001). Aorta disease represented the main reason for the overall increased mortality with a hazard ratio of 194.6 (CI 67.4-561.7, p < 0.0001); men 208.7 (CI 53.8-809.1, p < 0.001); women 173.4 (CI 31.5-954.5, p < 0.001). In addition, an unexplained mortality due to respiratory illness was not attributed to pneumothorax. Excluding cardiovascular and respiratory causes of death, we found no indication that MFS is associated with increased mortality for other reasons.

A complex phenotype in a family with a pathogenic SOX3 missense variant

Duplications and deletions of Xq26-27 including SOX3 (Xq27.1) have been associated with X-linked mental retardation and isolated growth hormone deficiency (OMIM 300123) or X-linked panhypopituitarism (OMIM 312000). Yet, pathogenic point mutations seem to be extremely rare. We report a family with three affected males with several clinical features including mild intellectual disability, microphthalmia, coloboma, hypopituitarism, facial dysmorphology and dental anomalies, including microcephaly, retrognathia and a solitary median maxillary central incisor amongst other features. Using Whole Exome Sequencing a missense variant in SOX3, NM_005634.2:c.449C>A; p.(Ser150Tyr) was identified. Segregation analysis in the family demonstrated that the variant was inherited through healthy females with its origin in the maternal grandmother showing germline mosaicism. Thus, we report one of the first cases of a pathogenic variant in SOX3 and germline mosaicism of this variant.

Acromelic frontonasal dysostosis and ZSWIM6 mutation: phenotypic spectrum and mosaicism

Acromelic frontonasal dysostosis (AFND) is a distinctive and rare frontonasal malformation that presents in combination with brain and limb abnormalities. A single recurrent heterozygous missense substitution in ZSWIM6, encoding a protein of unknown function, was previously shown to underlie this disorder in four unrelated cases. Here we describe four additional individuals from three families, comprising two sporadic subjects (one of whom had no limb malformation) and a mildly affected female with a severely affected son. In the latter family we demonstrate parental mosaicism through deep sequencing of DNA isolated from a variety of tissues, which each contain different levels of mutation. This has important implications for genetic counselling.

Prevalence, incidence, and age at diagnosis in Marfan Syndrome

BACKGROUND

Marfan syndrome is a genetic disorder with considerable morbidity and mortality. Presently, clinicians use the 2010 revised Ghent nosology, which includes optional genetic sequencing of the FBN1 gene, to diagnose patients. So far, only a few studies based on older diagnostic criteria have reported a wide range of prevalence and incidence. Our aim was to study prevalence, incidence, and age at diagnosis in patients with Marfan syndrome.

METHOD

Using unique Danish patient-registries, we identified all possible Marfan syndrome patients recorded by the Danish healthcare system (1977-2014). Following, we confirmed or rejected the diagnosis according to the 2010 revised Ghent nosology.

RESULTS

We identified a total of 1628 persons with possible Marfan syndrome. We confirmed the diagnosis in 412, whereof 46 were deceased, yielding a maximum prevalence of 6.5/100,000 at the end of 2014. The annual median incidence was 0.19/100,000 (range: 0.0-0.7) which increased significantly with an incidence rate ratio of 1.03 (95% CI: 1.02-1.04, p < 0.001). We found a median age at diagnose of 19.0 years (range: 0.0-74). The age at diagnosis increased during the study period, uninfluenced by the changes in diagnostic criteria. We found no gender differences.

CONCLUSION

The increasing prevalence of Marfan syndrome during the study period is possibly due to build-up of a registry. Since early diagnosis is essential in preventing aortic events, diagnosing Marfan syndrome remains a task for both pediatricians and physicians caring for adults.

Monozygotic twins with a de novo 0.32 Mb 16q24.3 deletion, including TUBB3 presenting with developmental delay and mild facial dysmorphism but without overt brain malformation

Nervous system development is highly dependent on the function of microtubules, which are assembled from tubulin heterodimers containing several α- and β-tubulin isotypes encoded by separate genes. A spectrum of neurological disorders with malformations of the central nervous system has recently been associated with missense mutations in this group of genes. Here, we report two patients, monozygotic twins, carrying a de novo 0.32 Mb deletion of chromosome 16q24.3 including the TUBB3 gene. The patients presented with global developmental delay, mild facial dysmorphism, secondary microcephaly, and mild spastic diplegia. Cerebral magnetic resonance imaging of the patients did not reveal cortical malformations, malformations of the corticospinal tracts, basal ganglia, corpus callosum, or optic nerves. This observation is in contrast to the group of neurological disorders that are associated with heterozygous missense mutations in genes encoding different neuronal α- and β-tubulin isotypes, termed tubulinopathies. On the background of current knowledge regarding the function and genotype-phenotype correlations of mutations in the neuronal tubulin isotypes, the clinical and diagnostic findings in these patients are discussed. To our knowledge, this is the first report of patients with a de novo deletion of the TUBB3 gene. The lack of cortical or other cerebral malformations supports the current hypothesis that TUBB3-related tubulinopathies are caused by altered protein function.

DVL1 frameshift mutations clustering in the penultimate exon cause autosomal-dominant Robinow syndrome

Robinow syndrome is a genetically heterogeneous disorder characterized by mesomelic limb shortening, genital hypoplasia, and distinctive facial features and for which both autosomal-recessive and autosomal-dominant inheritance patterns have been described. Causative variants in the non-canonical signaling gene WNT5A underlie a subset of autosomal-dominant Robinow syndrome (DRS) cases, but most individuals with DRS remain without a molecular diagnosis. We performed whole-exome sequencing in four unrelated DRS-affected individuals without coding mutations in WNT5A and found heterozygous DVL1 exon 14 mutations in three of them. Targeted Sanger sequencing in additional subjects with DRS uncovered DVL1 exon 14 mutations in five individuals, including a pair of monozygotic twins. In total, six distinct frameshift mutations were found in eight subjects, and all were heterozygous truncating variants within the penultimate exon of DVL1. In five families in which samples from unaffected parents were available, the variants were demonstrated to represent de novo mutations. All variant alleles are predicted to result in a premature termination codon within the last exon, escape nonsense-mediated decay (NMD), and most likely generate a C-terminally truncated protein with a distinct -1 reading-frame terminus. Study of the transcripts extracted from affected subjects' leukocytes confirmed expression of both wild-type and variant alleles, supporting the hypothesis that mutant mRNA escapes NMD. Genomic variants identified in our study suggest that truncation of the C-terminal domain of DVL1, a protein hypothesized to have a downstream role in the Wnt-5a non-canonical pathway, is a common cause of DRS.

The prevalence of CHD7 missense versus truncating mutations is higher in patients with Kallmann syndrome than in typical CHARGE patients

CONTEXT

Mutations in CHD7, a gene previously implicated in CHARGE (coloboma, heart defect, choanal atresia, retardation of growth and/or development, genital hypoplasia, ear anomalies) syndrome, have been reported in patients presenting with Kallmann syndrome (KS) or congenital hypogonadotropic hypogonadism (CHH). Most mutations causing CHARGE syndrome result in premature stop codons and occur de novo, but the proportion of truncating vs nontruncating mutations in KS and CHH patients is still unknown.

OBJECTIVE

The objective of the study was to determine the nature, prevalence, mode of transmission, and clinical spectrum of CHD7 mutations in a large series of patients.

DESIGN

We studied 209 KS and 94 CHH patients. These patients had not been diagnosed with CHARGE syndrome according to the current criteria. We searched for mutations in 16 KS and CHH genes including CHD7.

RESULTS

We found presumably pathogenic mutations in CHD7 in 24 KS patients but not in CHH patients. Nontruncating mutations (16 missense and a two-codon duplication) were more prevalent than truncating mutations (three nonsense, three frame shift, and a splice site), which contrasts with patients presenting with typical CHARGE syndrome. Thus, the clinical spectrum associated with CHD7 mutations may be partly explained by genotype/phenotype correlations. Eight patients also had congenital deafness and one had a cleft lip/palate, whereas six had both. For 10 patients, the presence of diverse features of the CHARGE spectrum in at least one relative argues against a de novo appearance of the missense mutation, and this was confirmed by genetic analysis in five families.

CONCLUSION

Considering the large prevalence and clinical spectrum of CHD7 mutations, it will be particularly relevant to genetic counseling to search for mutations in this gene in KS patients seeking fertility treatment, especially if KS is associated with deafness and cleft lip/palate.

Crouzon syndrome associated with acanthosis nigricans: prenatal 2D and 3D ultrasound findings and postnatal 3D CT findings

Crouzon syndrome with acanthosis nigricans (CAN) is a very rare condition with an approximate prevalence of 1 per 1 million newborns. We add the first report on prenatal 2D and 3D ultrasound findings in CAN. In addition we present the postnatal 3D CT findings. The diagnosis was confirmed by molecular testing.

RUNX2 analysis of Danish cleidocranial dysplasia families

Cleidocranial dysplasia (CCD) is an autosomal dominant inherited disease caused by mutations in the Runt gene RUNX2. Screening of 19 Danish CCD families revealed 16 pathogenic mutations (84%) representing 8 missense mutations, 2 nonsense mutations, 4 frame-shift mutations and 2 large deletions in the RUNX2 locus. Eight mutations were novel, two were found twice, and polymorphisms were found in the promoter region and in the conserved polyglutamine/polyalanine repeat. A large duplication downstream of RUNX2 found in one patient suggests a possible regulatory RUNX2 element. The CCD phenotypes and genotypes adhere to the large phenotypic variability reported in previous CCD studies. Identification of large chromosome aberrations in or near the RUNX2 locus in 3 of the 19 cases suggests copy number analyses to be included in future RUNX2 mutation analyses.

Levels of synthetic antioxidants (ethoxyquin, butylated hydroxytoluene and butylated hydroxyanisole) in fish feed and commercially farmed fish

Several synthetic antioxidants are authorized for use as feed additives in the European Union. Ethoxyquin (EQ) and butylated hydroxytoluene (BHT) are generally added to fish meal and fish oil, respectively, to limit lipid oxidation. The study was conducted to examine the concentrations of EQ, BHT and butylated hydroxyanisole (BHA) in several commercially important species of farmed fish, namely Atlantic salmon, halibut and cod and rainbow trout, as well as concentrations in fish feed. The highest levels of BHT, EQ and BHA were found in farmed Atlantic salmon fillets, and were 7.60, 0.17 and 0.07 mg kg(-1), respectively. The lowest concentrations of the synthetic antioxidants found were in cod. The concentration of the oxidation product ethoxyquin dimer (EQDM) was more than ten-fold higher than the concentration of parent EQ in Atlantic salmon halibut and rainbow trout, whereas this dimer was not detected in cod fillets. The theoretical consumer exposure to the synthetic antioxidants EQ, BHA and BHT from the consumption of farmed fish was calculated. The contribution of EQ from a single portion (300 g) of skinned fillets of the different species of farmed fish would contribute at most 15% of the acceptable daily intake (ADI) for a 60 kg adult. The consumption of farmed fish would not contribute measurably to the intake of BHA; however, a 300 g portion of farmed Atlantic salmon would contribute up to 75% of the ADI for BHT.

Transmitted cytogenetic abnormalities in patients with mental retardation: Pathogenic or normal variants?

Knowing the origin of cytogenetic abnormalities detected in individuals with mental retardation and dysmorphic features is essential to genetic counselling of affected families. To illustrate this, we report on six families with transmitted cytogenetic abnormalities and discuss the genotype-phenotype correlations, including the possibility of the abnormalities being normal genomic variants. The abnormalities were detected using metaphase HR-CGH; their size was estimated to range from 1.6 to 7.5 Mb using tiling path array-CGH and real-time PCR. The abnormalities were transmitted through two to four generations and included interstitial deletions of 1p31.3-p32.1, 2q13, 10q11.21-q11.23, and 13q31.1; a duplication of 1p34.1-p34.2; and in one family both a deletion of 18q21.1 and a duplication of 4q35.1-q35.2. The probands were mentally retarded and had nonspecific dysmorphic features except for one patient with the Bohring-Opitz syndrome. We considered the abnormalities in two families to be clinically significant: In one family, the proband's brain abnormality was comparable to previously reported abnormalities in individuals with a similar duplication of 1p31-p32. Congenital heart disease was previously mapped to the chromosomal region of 18q that was affected in the proband of another family. The carrier parents in both families had mild clinical features. In two families the abnormalities were considered as coincidental findings, and in two further families the abnormalities were insufficient to explain the phenotypes of the probands but possibly were related to a milder phenotype in other family members. These cases illustrate the need for careful assessment of the extended family in order to interpret the phenotypic consequences of abnormalities identified using array-CGH.

Analysis of 65 tuberous sclerosis complex (TSC) patients by TSC2 DGGE, TSC1/TSC2 MLPA, and TSC1 long-range PCR sequencing, and report of 28 novel mutations

Tuberous sclerosis complex (TSC) is a severe autosomal-dominant disorder characterized by the development of benign tumors (hamartomas) in many organs. It can lead to intellectual handicap, epilepsy, autism, and renal or heart failure. An inactivating mutation in either of two tumor-suppressor genes-TSC1 and TSC2-is the cause of this syndrome, with TSC2 mutations accounting for 80-90% of all mutations. Molecular diagnosis of TSC is challenging, since TSC1 and TSC2 consist of 21 and 41 coding exons, respectively, and the mutation spectrum is very heterogeneous. Here we report a new approach for detecting mutations in TSC: a denaturing gradient gel electrophoresis (DGGE) analysis for small TSC2 mutations, a multiplex ligation-dependent probe amplification (MLPA) analysis for large deletions and duplications in TSC1 or TSC2, and a long-range PCR/sequencing-based analysis for small TSC1 mutations. When applied in this order, the three methods provide a new sensitive and time- and cost-efficient strategy for the molecular diagnosis of TSC. We analyzed 65 Danish patients who had been clinically diagnosed with TSC, and identified pathogenic mutations in 51 patients (78%). These included 36 small TSC2 mutations, four large deletions involving TSC2, and 11 small TSC1 mutations. Twenty-eight of the small mutations are novel. For the missense mutations, we established a functional assay to demonstrate that the mutations impair TSC2 protein function. In conclusion, the strategy presented may greatly help small- and medium-sized laboratories in the pre- and postnatal molecular diagnosis of TSC.

Mapping genomic deletions down to the base: a quantitative copy number scanning approach used to characterise and clone the breakpoints of a recurrent 7p14.2p15.3 deletion

With the recent advances in genomic research, it has become apparent that a substantial part of human malformation and mental retardation is caused by imbalances in genomic content. Thus, there is an increasing need for versatile methods allowing a detailed mapping and cloning of the actual rearrangements. We have combined the flexibility of real-time quantitative PCR with the knowledge of human genome sequence to perform a copy number scanning in three patients known to harbour a deletion in the 7p14p15 locus. In two of the patients the actual breakpoints were cloned and sequenced, whereas the breakpoint of the third patient was mapped to a region previously predicted to be prone for rearrangements. One patient also harboured an inversion in connection with the deletion that disrupted the HDAC9 gene. All three patients showed clinical characteristics reminiscent of the hand-foot-genital syndrome and were deleted for the entire HOXA cluster. Two patients were also deleted for DFNA5, a gene implicated in dominant nonsyndromic hearing impairment, but neither patient showed signs of reduced hearing capabilities. The described copy number scanning approach is largely independent of the genomic locus and may be a valuable tool for characterising a large spectrum of deletions.

Lactic acid bacteria and the human gastrointestinal tract

OBJECTIVE

This review summarises the effects of lactic acid bacteria on lactose malabsorption, bacterial/viral or antibiotic associated diarrhoea, and describes the impact of lactic acid bacteria on cancer and the fermentative products in the colon.

RESULTS

Eight studies (including 78 patients) demonstrated that lactase deficient subjects absorbed lactose in yogurt better than lactose in milk, while two studies (25 patients) did not support this. Two studies (22 patients) showed that unfermented acidophilus milk was absorbed better than milk, while six studies (68 patients) found no significant differences. Addition of lactose hydrolysing enzyme, lactase, to milk improved lactose malabsorption in seven studies (131 lactose malabsorbers), while one study (10 malabsorbers) demonstrated no improvement. Lactic acid bacteria alleviated travellers' diarrhoea in one study (94 individuals) while a study including 756 individuals was borderline statistically significant. One study (50 individuals) did not find an effect of lactic acid bacteria on travellers' diarrhoea. Six studies (404 infants) demonstrated a significant effect of lactic acid bacteria on infant diarrhoea, while one study (40 infants) did not. Lactic acid bacteria moderated antibiotic associated diarrhoea in three studies (66 individuals), while two studies (117 individuals) were insignificant.

CONCLUSIONS

Lactase deficient subjects benefit from a better lactose absorption after ingestion of yoghurt compared with milk and from milk added lactase, whereas ingestion of unfermented acidophilus milk does not seem to improve lactose absorption. The majority of studies support that lactic acid bacteria alleviate bacterial/viral induced diarrhoea, especially in infants, while the effect on antibiotic associated diarrhoea is less clear. Experimental studies indicate an effect of lactic bacteria on human cell cancer lines, but clinical evidence is lacking. A 'stabilising' effect of lactic acid bacteria on the colonic flora has not been documented.

Colonic production of butyrate in patients with previous colonic cancer during long-term treatment with dietary fibre (Plantago ovata seeds)

BACKGROUND

Butyrate has antineoplastic properties against colorectal cancer cells and is the preferred oxidative substrate for colonocytes. Like acetate and propionate (short-chain fatty acids; SCFAs), butyrate is produced by colonic fermentation of dietary fibre.

METHODS

Twenty patients resected for colorectal cancer were treated with 20 g/day of the fibre Plantago ovata seeds for 3 months, which increased the intake of fibre by 17.9 +/- 0.8 g/day, from basal levels of 19.2 +/- 1.7 g/day; 17 patients completed the study. Faecal samples were obtained on eight occasions, twice before treatment, and monthly three times during and three time after treatment.

RESULTS

One month of fibre therapy increased faecal concentrations of butyrate by 42 +/- 12% (from 13.2 +/- 1.2 to 19.3 +/- 3.0 mmol/l; P < 10(-4)), acetate by 25 +/- 6% (P < 10(-4)), propionate by 28 +/- 9% (P = 0.01), and total SCFAs by 25 +/- 6% (P < 10 (-4)). Concentrations were increased during the 3-month fibre treatment but reversed to pretreatment levels within 1 to 2 months after cessation of fibre supplementation. The relative concentration (ratio) of butyrate was not altered owing to a simultaneous increase in acetate and propionate. Faecal pH decreased initially but was normalized after 2 months of fibre supplements. Fibre therapy increased the 24-h productions of butyrate by 47 +/- 10% (P < 10(-4)) and acetate by 50 +/- 7% (P < 10(-4)) in 16.6% faecal homogenates with added P. ovata seeds (20mg/ml), but SCFA productions returned to pretreatment levels after discontinuation of additional fibre intakes.

CONCLUSIONS

Oral intake of P. ovata seeds adapted the colonic flora to increase the production of butyrate (and acetate) from this fibre and increased faecal concentrations of butyrate by 42% in patients resected for colonic cancer. The effects depended on continuity of treatment.

Antibiotic-associated diarrhoea, Clostridium difficile, and short-chain fatty acids

BACKGROUND

It has been hypothesized that Clostridium difficile and decreased colonic production of short-chain fatty acids (SCFAs) cause the development of antibiotic-associated diarrhoea. We therefore wanted to investigate the effects of an intensive and uniform antibiotic therapy on faecal SCFAs concentrations. C. difficile, and extent of diarrhoea.

METHODS

Fifteen liver-transplanted patients who received oral bowel flora suppression therapy (6.3 g cefuroxime, 0.6 g tobramycin, and 0.5 g nystatin three times daily) were studied for 12 days before and 12 days after discontinuation of therapy.

RESULTS

Thirteen of the 15 patients (87%) developed diarrhoea. Colonic fermentation was negligible in all patients, judged by very low levels of faecal SCFAs (< 10 mmol/l). Diarrhoea lessened as suppression therapy proceeded despite continuous low levels of SCFAs. Initial stool frequency of 4.1 +/- 0.6 and viscosity of 2.5 +/- 0.2 per day (on a scale of 1-3; mean +/- SE) decreased to 2.2 +/- 0.5 (p = 0.0009) and 1.6 +/- 0.2 (p = 0.003) per day, respectively, just before cessation of suppression therapy. Both SCFAs and stool habits normalized within days after discontinuation of antibiotics. Only a few samples from 2 patients were culture-positive for C. difficile during therapy, whereas 9 of the 15 patients (60%) became culture-positive (6 cytotoxin-positive) after cessation of suppression therapy at a time when none had diarrhoea.

CONCLUSIONS

Intensive treatment with antibiotics directed against the colonic flora resulted in diarrhoea in the vast majority of patients, but the diarrhoea was self-limiting despite continual antibiotic treatment and very low faecal concentrations of SCFAs. C. difficile was not associated with antibiotic-associated diarrhoea but was a common finding after treatment with antibiotics was stopped at the time when diarrhoea had ceased.

Short-chain fatty acids in the non-adapted and adapted pelvic ileal pouch

BACKGROUND

Adaptation to colonic conditions occurs in the bacterial flora and faecal short-chain fatty acids (SCFAs) of the pelvic ileal pouch.

METHODS

Faecal SCFAs were studied in 14 J-pouch patients within 10 days after closure of the ileostomy (non-adapted pouch) and more than 6 months after ileostomy closure (adapted pouch).

RESULTS

Concentrations of faecal SCFAs were low in non-adapted pouches (mean +/- SE, 20.3 +/- 3.4 mmol/l), increasing to intermediate levels, 53.3 +/- 8.4 mmol/l, between 6 months and a year after ileostomy closure, and to 96.3 +/- 7.9 mmol/l, after more than a year of adaptation. Production of SCFAs in faecal homogenates was correspondingly low in non-adapted (6.3 +/- 2.0 mmol/l) compared with adapted pouches (32.0 +/- 3.6 mmol/l; p = 0.001) and could not be overcome by the addition of fermentable carbohydrates. Percentages of the predominant SCFAs (acetate, propionate, butyrate) were not affected by adaptation, nor were production and concentration of lactate. Stool volume decreased from 1019 +/- 134 to 603 +/- 77 ml/24 h (p = 0.02) during adaptation, sodium excretion decreased from 132 +/- 19 to 67 +/- 11 mmol/24 h (p = 0.02), and osmolality increased from 316 +/- 6 to 398 +/- 13 (p = 0.001). Excretions of carbohydrates, nitrogen, and potassium were not altered.

CONCLUSIONS

The bacterial production of SCFAs is low in non-adapted pouches, resulting in low concentrations of SCFAs comparable to concentrations found in conventional ileostomies. Pouch adaptation gradually increases SCFA production and concentration severalfold and reaches concentrations normally found in non-colectomized individuals after approximately 1 year.

Stimulation of butyrate absorption in the human rectum in vivo

BACKGROUND

Models of short-chain fatty acid absorption have focused on the stimulation of sodium absorption, an effect mainly located in the proximal colon of man. With the present efforts to utilize butyrate enemas as a treatment of ulcerative colitis, it seemed important to assess the transport in the rectum.

METHODS

Non-equilibrium dialysis of the rectum was applied by placing dialysis bags containing various electrolyte solutions in the rectum of volunteers for 30 min. In this period changes in ion concentrations were linear with time. Net absorption and secretion rates were calculated from the change in fluid composition.

RESULTS

Sodium absorption was highest (24 +/- 8 mumol/cm2 h) in the presence of chloride and lowest (16 +/- 2 mumol/cm2 h) in the presence of bicarbonate and butyrate. Butyrate (70 mmol/l) was absorbed at a high rate of 7.1 +/- 2.2 mumol/cm2 h, independent on the presence of chloride, and was accompanied by increased bicarbonate secretion. Butyrate absorption increased to 9.6 +/- 1.8 mumol/cm2 h in sodium-free high-potassium media containing bicarbonate.

CONCLUSION

The results show that it is possible to increase butyrate uptake by manipulation of the electrolyte composition in the rectal lumen. Maximal uptake occurred with an electrolyte composition that was similar to the natural rectal content. The information gathered could be useful in designing enemas for trial in ulcerative colitis, provided the findings can be confirmed in these patients.

Influence of intestinal inflammation (IBD) and small and large bowel length on fecal short-chain fatty acids and lactate

Treatment with short-chain fatty acids (SCFAs) seems promising in ulcerative colitis and changes in colonocyte oxidation of butyrate have been suggested to be of importance for the development of this disease. The influence of small and large bowel length after surgery on SCFAs is only partly known. SCFAs and lactate were measured in consecutive fecal samples from 300 patients with ulcerative colitis (103), Crohn's disease (127), and noninflammatory bowel disease (70); 205 had had surgery, 52 had short bowels (< 200 cm). Lactate (mainly the L-isomer) was elevated in ulcerative colitis patients with pancolitis (mean +/- SEM, 17 +/- 5 mmol/liter) and proctitis (12 +/- 3 mmol/liter) compared with quiescent ulcerative colitis (3 +/- 1 mmol/liter, P < 0.01), and correlated with the index of Truelove (R = 0.52, P < 0.0005). Lactate was also increased in Crohn's colitis (21 +/- 8 mmol/liter), but not in isolated ileitis (4 +/- 2 mmol/liter), compared with quiescent Crohn's disease (7 +/- 2 mmol/liter, P < 0.02), but did not correlate with the activity index (CDAI; R = 0.18, P = 0.12). In contrast to earlier reports, SCFAs (including butyrate) did not correlate with inflammatory activity or localization in either ulcerative colitis or Crohn's disease. The length of the small bowel had no influence on SCFAs and lactate in patients with either no colonic function (ileostomies), or with > 50% and < 50% preserved colorectal length, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Butyrate absorption and lactate secretion in ulcerative colitis

PURPOSE

Fecal electrolytes and organic anion concentrations are altered in ulcerative colitis, presumably reflecting changes in colon epithelial transport. Information of mucosal absorption of butyrate in active ulcerative proctosigmoiditis is not available.

METHODS

Dialysis bags containing 70 mmol/liter of butyrate in an isotonic electrolyte solution were placed in the rectum for 30 minutes. Net absorption or secretion rates of butyrate, lactate, and electrolytes were determined in the rectum of 12 patients with active ulcerative colitis (UC) and in 10 patients with quiescent UC and then compared with 10 healthy controls.

RESULTS

Net flux rates demonstrated a considerable absorption of butyrate in patients with active inflammation of 7.5 +/- 0.4 mumol/cm2/h and quiescent colitis of 6.6 +/- 0.4 mumol/cm2/h, equal to absorption in healthy controls of 6.3 +/- 0.5 mumol/cm2/h, P = 0.12. Despite normal butyrate absorption, sodium absorption was compromised in active ulcerative colitis (11.5 +/- 1.4 mumol/cm2/h) compared with quiescent (15.4 +/- 1.0 mumol/cm2/h) and controls (18.7 +/- 0.8 mumol/cm2/h) (P = 0.0006). Mucosal secretion of L-lactate was minimal in both healthy controls and quiescent UC but significantly increased in patients with proctosigmoiditis (0.2 +/- 0.1 mumol/cm2/h, 0.2 +/- 0.1 mumol/cm2/h vs. 0.9 +/- 0.2 mumol/cm2/h; P = 0.0001). Appearance of D-lactate was negligible in all three groups.

CONCLUSIONS

This study demonstrates that rectal butyrate absorption is normal in UC, and it follows that butyrate supplied in enemas can be expected to be absorbed. The inflamed colonic mucosa secretes L-lactate, and the increased fecal lactate concentrations can be explained by mucosal origin of lactate.

Colonic lactate metabolism and D-lactic acidosis

D-Lactic acidosis is seen in patients with intestinal bypass or short bowels in whom colonic produced D-lactate accumulates. An intestinal bypassed patient with D-lactic acidosis had higher fecal D-lactate (122.4 mmol/liter) and L-lactate (90.1 mmol/liter) than described before in humans. D-Lactate fluctuated between 0.5 and 3.1 mmol/liter in plasma (normal < 0.1 mmol/liter) and between 1.1 and 52.8 mmol/liter in urine (normal < 0.7 mmol/liter) within a few hours, indicating that the human organism do metabolize and excrete D-lactate. The patient with D-lactic acidosis had a 10-fold increased DL-lactate production from glucose in fecal homogenates compared to 14 healthy controls and a patient with intestinal bypass, who did not have D-lactic acidosis. A 67% carbohydrate (starch)-enriched diet resulted in a minor elevation of fecal and plasma lactate, whereas 50 + 100 + 150 g of ingested lactose increased D-lactate in feces (84.0 mmol/liter) and plasma (2.3 mmol/liter) considerably in the patient with D-lactic acidosis. Intestinal prolongation (22 cm ileum) had a temporary effect on fecal and plasma D-lactate, but intestinal continuity was reestablished 26 months later because D-lactic acidosis recurred (plasma 8.6 mmol/liter, urine 101.3 mmol/liter). Large amounts of lactulose (160 g/day) to 12 normal individuals increased D-lactate to 13.6 +/- 3.5 mmol/liter in feces, but never increased D-lactate in plasma or urine. The in vitro fermentation of glucose in fecal homogenates increased DL-lactate, which disappeared after complete metabolization of the glucose. L-Lactate was converted to D-lactate and vice versa, and both were degraded to the short-chain fatty acids acetate, propionate, and butyrate. An infrequent, but elevated ability of the colonic flora to produce lactate may be a prerequisite for D-lactic acidosis to occur and may explain why the syndrome is so seldom seen even in patients with intestinal bypass or short bowels. The suggestion that D-lactate is not metabolized and hence accumulates is probably not valid.

Faecal DL-lactate concentration in 100 gastrointestinal patients

The relation between faecal DL-lactate and intestinal inflammation or malabsorption was evaluated in 100 nonselected inpatients at a referral center for gastrointestinal disorders. Twenty-one (21%) had DL-lactate concentrations (range, 8-95 mmol/l) above the 95% limit (6.1 mmol/l) in healthy individuals. Inflammatory bowel disease with active proctitis was associated with increased faecal DL-lactate in 11 of 15 patients (73%) (mean, 32 mmol/l; range, 8-95 mmol/l) and in the 1 patient with pouchitis (8 mmol/l), whereas only 1 of 8 patients (13%) with active inflammatory bowel disease without proctitis had L-lactate elevation (25 mmol/l). Among 26 patients with malabsorption and quiescent or noninflammatory bowel disease, 3 of 17 (18%) with preserved colonic function and 3 of 9 (33%) with jejunostomy had increased faecal lactate. Only 2 of 50 (4%) patients with neither active inflammatory bowel disease nor malabsorption had faecal DL-lactate elevation. In vitro bacterial fermentation of most dietary polysaccharides did not cause accumulation of lactate, corresponding to a lack of correlation between faecal carbohydrate excretion and lactate accumulation. An isolated increase in faecal L-lactate was observed in 6 of 13 patients with inflammatory bowel disease, whereas D-lactate was not increased without a simultaneous increase of the L-lactate isomer. In conclusion, the faecal lactate concentration was frequently increased in patients with inflammatory bowel disease and proctitis, occasionally increased in patients with severe malabsorption, and often normal in patients with quiescent inflammatory bowel disease or localized Crohn's ileitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of lactic acid bacteria on the intestinal production of lactate and short-chain fatty acids, and the absorption of lactose

The characteristic fermentation pattern seen with specific saccharides in incubations with pure cultures of Lactobacillus acidophilus and Bifidobacterium bifidum disappeared when incubated in 16.7% fecal homogenate. The productions of lactate and short-chain fatty acids in mixed bacterial-fecal incubations were similar to productions in fecal homogenates without L acidophilus and B bifidum and were mainly associated with the specific mono-, di-, and polysaccharides added to the incubate. B bifidum was cultured from ileostomic contents in eight of nine ileostomists after oral administration (2.4 x 10(10) cells), but did not influence the concentrations and productions of DL-lactate and short-chain fatty acids in the ileostomic outputs and incubates. Large amounts of ingested lactic acid bacteria (4.2 x 10(10) cells) did not ameliorate lactose malabsorption measured by the breath-hydrogen test in 12 lactose malabsorbers. This study shows that ingested lactic acid bacteria are indeed present in the colon, but it does not support the theory that they change the pattern of colonic fermentation or the degree of intestinal lactose malabsorption.

Anti-cardiolipin antibodies (IgG and IgA) in women with recurrent fetal loss correlate to clinical and serological characteristics of SLE

AIM OF STUDY

We investigated to which degree IgG, IgA and IgM anti-cardiolipin antibodies (aCL) are associated in recurrent abortion or late fetal death with other signs of autoimmune disease and in particular SLE.

MATERIAL AND METHODS

Serological variables typical of SLE and of the anti-phospholipid antibody syndrome were measured once eight to 16 weeks after the last fetal loss in 158 women with recurrent abortion or late fetal death; women with manifest autoimmune rheumatic disease were excluded.

RESULTS

(1) Positive values, i.e. above the 99th percentile of reference material, of IgG aCL and IgA aCL were observed in 4% and 7%, respectively, whereas 26% had positive values of IgM aCL. (2) IgG aCL and IgA aCL but not IgM aCL correlated to anti-nuclear antibodies and to anti-double stranded DNA. (3) Anti-double stranded DNA, IgG aCL and IgA aCL but not IgM aCL correlated to previous occurrence of thrombosis. (4) ANA correlated to lower blood platelet concentrations and higher erythrocyte sedimentation rates.

CONCLUSIONS

Women with recurrent abortion or late fetal death who have higher but not necessarily abnormally high levels of IgG aCL or IgA aCL constitute a group with increased occurrence of clinical and serological characteristics of SLE. We suggest that these women be kept under surveillance for future development of autoimmune disease especially SLE. The women with high IgM aCL constitute another group without these characteristics.

Lactate and pH in faeces from patients with colonic adenomas or cancer

Earlier studies have reported that faecal pH is more alkaline in patients with colonic cancer, indicating a reduction in colonic carbohydrate fermentation to organic acids. The pH of faeces from 11 pre and 14 postoperative, selected colonic cancer patients without intestinal obstruction, major loss of appetite or weight, not treated with antibiotics, and without signs of dissemination or recurrence of the cancer, did not differ, however, from faecal pH in 17 patients with previous colonic adenomas removed by polypectomy and faecal pH in 17 age matched (mean 61 years) healthy controls (mean (SE) 7.03 (0.10), 7.15 (0.11), 7.20 (0.12), 7.11 (0.12) respectively; p = 0.82). Faecal pH in 20 younger (mean 32 years) healthy controls tended to be lower (6.89 (0.07) compared with the older age matched control group (p < 0.06). Faecal concentrations of D-, L- or total D+L-lactate did not differ between the patients with present or previous colonic cancer, adenomas, and the healthy controls (D+L-lactate mean (SE) 3.2 (0.5), 3.1 (0.3), 3.5 (0.7), 4.1 (1.0) mmol/l respectively; p = 0.72), and the production pattern of lactate from different carbohydrates (glucose and dietary fibre) in 16.6% faecal homogenates was similar in all the three groups of patients and the healthy controls. Faecal pH was changed within days by modifications of the diet. An enteral diet free of fibre, starch, and lactose increased faecal pH within three days, whereas pH decreased when the colonic load of carbohydrates was increased by lactulose. Therefore, the reported alkaline faecal pH in patients with colonic cancer may reflect short term reduction in dietary intake and colonic fermentation secondary to the presence of the cancer, especially in patients with advanced disease, rather than long term differences in the precancer dietary habits.

Colonic fermentation of ispaghula, wheat bran, glucose, and albumin to short-chain fatty acids and ammonia evaluated in vitro in 50 subjects

The production of short-chain fatty acids and ammonia was measured in 16.6% fecal homogenates from 50 subjects incubated at 37 degrees C for 6 and 24 hours. All 50 homogenates produced ammonia and short-chain fatty acids of any chain length (C2-C5). Incubation for 24 hours with dietary fiber (ispaghula husk or wheat bran), albumin, or glucose (10 mg/mL) increased the short-chain fatty acid production (43.6 +/- 2.8, 45.4 +/- 2.0, 60.3 +/- 3.2, and 65.8 +/- 3.1 mmol/L, respectively) compared with controls (21.4 +/- 1.3 mmol/L). The degradation of different substrates was associated with the production of different amounts of ammonia and short-chain fatty acids. Ispaghula, wheat bran, albumin, and glucose were fermented to acetate (> 2 mmol/L; 24-hour incubations) in 86%, 96%, 98%, and 98% of the homogenates, to propionate in 80%, 76%, 100%, and 68%, and to butyrate in 32%, 94%, 88%, and 54% of the homogenates, respectively. Isobutyrate, valerate, and isovalerate were produced from albumin in all (100%) of the homogenates, but only in 2 to 4% of the homogenates incubated with ispaghula or glucose. Ammonia was always (100%) produced after the addition of albumin and always (98%) consumed (assimilated) when glucose was fermented. Surgery (sigmoid or right- or left-sided colonic resection) did not change the pattern of ammonia and short-chain fatty acid production from these substrates. This study suggests that the different colonic flora from a large number of subjects share general biochemical characteristics, which metabolize different substrates to specific patterns of ammonia and short-chain fatty acids.

The colon in carbohydrate malabsorption: short-chain fatty acids, pH, and osmotic diarrhoea

Short-chain (C2-C6) fatty acids (SCFA) are the major anions in colonic contents and the result of anaerobic fermentation of mainly saccharides. The effects and regulation of saccharide fermentation were studied in vitro and in vivo. In vitro faecal incubation was used to study the effects of lactose, glucose, and galactose and of pH on SCFA formation. Changing the pH to below 5 or above 11 abolished SCFA formation in the faecal incubates; in the pH 5-9 interval SCFA production was high, with only minor pH dependence. Adding glucose, galactose, or lactose to the incubation system increased SCFA production, but at high saccharide concentrations (100-300 mmol/l) SCFA formation was inhibited by the pH change. In vivo disaccharide malabsorption with increasing doses of lactulose caused a decrease in faecal pH to less than 5, values inhibitory to fermentation, before the appearance of carbohydrate in faeces. In 6 of 12 volunteers diarrhoea occurred suddenly and was caused by malabsorbed non-fermented carbohydrate. The six other volunteers had a gradual increase in faecal output with lactulose dose and developed diarrhoea before the appearance of saccharide in faeces. The intake of lactulose tolerated before diarrhoea ensued varied between individuals, with the majority having diarrhoea of more than 11/day at 160 g lactulose per day. At this dose SCFA absorption was estimated to be in the range 550 to 1150 mmol/day.

Fermentation to short-chain fatty acids and lactate in human faecal batch cultures. Intra- and inter-individual variations versus variations caused by changes in fermented saccharides

The fermentation to short-chain fatty acids, lactate, and ammonia from several non-starch polysaccharides, glucose, and albumin was investigated in 16.6% faecal homogenates. Increasing concentrations (0-30 mg/ml) of glucose, wheat bran, pectin, ispaghula, cellulose, or albumin incubated for 24 h in homogenates pooled from three individuals increased short-chain fatty acid production linearly. Amounts and ratios of short-chain fatty acids formed were highly dependent on the type of substrate fermented. Fermentable saccharides increased ammonia assimilation, in contrast to the metabolic inert cellulose. Nine faecal homogenates sampled from three individuals at three occasions were incubated for 6 and 24 h. The production of total short-chain fatty acids, acetate, propionate, and butyrate and the accumulation of D- and L-lactate changed considerably in relation to the type of substrate added (cellulose, ispaghula, wheat bran, pectin, gum arabic, and glucose; p less than 10(-4)-10(-7). In contrast, there were no significant (p greater than 0.05) differences in organic acid formation between the nine homogenates, and the intra- and inter-individual variations were of the same magnitude. Variations in fermentation, when measured as organic acid formation, were therefore related to the type of substrate fermented rather than the individual tested.