Wladimir Wertelecki

Human Ehlers-Danlos Syndrome Type VII C and Bovine Dermatosparaxis Are Caused by Mutations in the Procollagen I N-Proteinase Gene

Ehlers-Danlos syndrome (EDS) type VIIC is a recessively inherited connective-tissue disorder, characterized by extreme skin fragility, characteristic facies, joint laxity, droopy skin, umbilical hernia, and blue sclera. Like the animal model dermatosparaxis, EDS type VIIC results from the absence of activity of procollagen I N-proteinase (pNPI), the enzyme that excises the N-propeptide of type I and type II procollagens. The pNPI enzyme is a metalloproteinase containing properdin repeats and a cysteine-rich domain with similarities to the disintegrin domain of reprolysins. We used bovine cDNA to isolate human pNPI. The human enzyme exists in two forms: a long version similar to the bovine enzyme and a short version that contains the Zn++-binding catalytic site but lacks the entire C-terminal domain in which the properdin repeats are located. We have identified the mutations that cause EDS type VIIC in the six known affected human individuals and also in one strain of dermatosparactic calf. Five of the individuals with EDS type VIIC were homozygous for a C-->T transition that results in a premature termination codon, Q225X. Four of these five patients were homozygous at three downstream polymorphic sites. The sixth patient was homozygous for a different transition that results in a premature termination codon, W795X. In the dermatosparactic calf, the mutation is a 17-bp deletion that changes the reading frame of the message. These data provide direct evidence that EDS type VIIC and dermatosparaxis result from mutations in the pNPI gene.

Neurofibromatosis 2: Clinical and DNA Linkage Studies of a Large Kindred

At least eight provisional categories of neurofibromatosis have been proposed. Among these, neurofibromatosis 1 (von Recklinghausens disease or peripheral neurofibromatosis) and neurofibromatosis 2 (central or bilateral acoustic neurofibromatosis) have been established as distinct disorders. We studied 15 affected male and 8 affected female members of one large kindred with neurofibromatosis 2. None of the patients met the diagnostic criteria for neurofibromatosis 1. Between the ages of 15 and 53 years, the patients had multiple central nervous system tumors of various types--mainly, bilateral acoustic neuromas. Two or more tumors eventually developed in 20 of the patients; 9 had evidence of only bilateral acoustic neuromas. Meningiomas and ependymomas were more common among the young patients; those who initially presented with acoustic neuromas were nearly a decade older. Intracranial nontumoral calcifications were present in most patients and were also found in symptom-free children. The presence of such lesions is probably a prodromic feature of neurofibromatosis 2. Simultaneous analysis of D22S1 and IGLV DNA markers for coinheritance with neurofibromatosis 2 indicates that the locus for the disease is near the center of the long arm of chromosome 22 (22q11.1----22q13.1). The eventual isolation of this disease gene may reveal a cause of the most common intracranial tumors in humans.

Paper 6: EUROCAT member registries: organization and activities

BACKGROUND EUROCAT is a network of population-based congenital anomaly registries providing standardized epidemiologic information on congenital anomalies in Europe. There are three types of EUROCAT membership: full, associate, or affiliate. Full member registries send individual records of all congenital anomalies covered by their region. Associate members transmit aggregate case counts for each EUROCAT anomaly subgroup by year and by type of birth. This article describes the organization and activities of each of the current 29 full member and 6 associate member registries of EUROCAT. METHODS Each registry description provides information on the history and funding of the registry, population coverage including any changes in coverage over time, sources for ascertaining cases of congenital anomalies, and upper age limit for registering cases of congenital anomalies. It also details the legal requirements relating to termination of pregnancy for fetal anomalies, the definition of stillbirths and fetal deaths, and the prenatal screening policy within the registry. Information on availability of exposure information and denominators is provided. The registry description describes how each registry conforms to the laws and guidelines regarding ethics, consent, and confidentiality issues within their own jurisdiction. Finally, information on electronic and web-based data capture, recent registry activities, and publications relating to congenital anomalies, along with the contact details of the registry leader, are provided. CONCLUSIONS The registry description gives a detailed account of the organizational and operational aspects of each registry and is an invaluable resource that aids interpretation and evaluation of registry prevalence data.

Isodicentric Y chromosome: cytogenetic, molecular and clinical studies and review of the literature

Dicentrics are among the most common structural abnormalities of the human Y chromosome. Predicting the phenotypic consequences of different duplications and deletions of dicentric Y chromosomes is usually complicated by varying degrees of mosaicism (45,X cell lines), which may, in some cases, remain undetected. Molecular studies in patients with dicentric Y chromosomes have been few, and only two studies have attempted to determine the presence of SRY (the putative testis-determining factor gene). We report an 18-year-old female with short stature, amenorrhea, hirsutism, hypoplastic labia minora, and clitoromegaly who has a 45,X/46,X,idic(Y)(p11.32)/47,X,idic(Y)(p11.32),idic(Y) (p11.32) karyotype. Southern analysis using Y-specific probes (Y97, 2D6, 1F5, pY3.4) and polymerase chain reaction (PCR) analysis using primers for ZFY and SRY were positive for all loci tested, indicating that almost all of the Y chromosome was present. Our findings and an extensive review of the literature emphasize the importance of molecular analyses of abnormal Y chromosomes before any general conclusions can be reached concerning the relative effects of the Y-chromosome abnormality and mosaicism on sexual differentiation.

The plausibility of maternal nutritional status being a contributing factor to the risk for fetal alcohol spectrum disorders: The potential influence of zinc status as an example

There is increasing evidence that human pregnancy outcome can be significantly compromised by suboptimal maternal nutritional status. Poor diet results in a maternal–fetal environment in which the teratogenicity of other insults such as alcohol might be amplified. As an example, there is evidence that zinc (Zn) can interact with maternal alcohol exposure to influence the risk for fetal alcohol spectrum disorders (FASD). Studies with experimental animals have shown that the teratogenicity of alcohol is increased under conditions of Zn deficiency, whereas its teratogenicity is lessened when animals are given Zn‐supplemented diets or Zn injections before the alcohol exposure. Alcohol can precipitate an acute‐phase response, resulting in a subsequent increase in maternal liver metallothionein, which can sequester Zn and lead to decreased Zn transfer to the fetus. Importantly, the teratogenicity of acute alcohol exposure is reduced in metallothionein knockout mice, which can have improved Zn transfer to the conceptus relative to wild‐type mice. Consistent with the above, Zn status has been reported to be low in alcoholic women at delivery. Preliminary data from two basic science and clinical nutritional studies that are ongoing as part of the international Collaborative Initiative on Fetal Alcohol Spectrum Disorders support the potential role of Zn, among other nutritional factors, relative to risk for FASD. Importantly, the nutrient levels being examined in these studies are relevant to general clinical populations and represent suboptimal levels rather than severe deficiencies. These data suggest that moderate deficiencies in single nutrients can act as permissive factors for FASD, and that adequate nutritional status or intervention through supplementation may provide protection from some of the adverse effects of prenatal alcohol exposure.

Epidemiology of congenital diaphragmatic hernia in Europe: a register-based study

Introduction Published prevalence rates of congenital diaphragmatic hernia (CDH) vary. This study aims to describe the epidemiology of CDH using data from high-quality, population-based registers belonging to the European Surveillance of Congenital Anomalies (EUROCAT). Methods Cases of CDH delivered between 1980 and 2009 notified to 31 EUROCAT registers formed the population-based case series. Prevalence over time was estimated using multilevel Poisson regression, and heterogeneity between registers was evaluated from the random component of the intercept. Results There were 3373 CDH cases reported among 12 155 491 registered births. Of 3131 singleton cases, 353 (10.4%) were associated with a chromosomal anomaly, genetic syndrome or microdeletion, 784 (28.2%) were associated with other major structural anomalies. The male to female ratio of CDH cases overall was 1:0.69. Total prevalence was 2.3 (95% CI 2.2 to 2.4) per 10 000 births and 1.6 (95% CI 1.6 to 1.7) for isolated CDH cases. There was a small but significant increase (relative risk (per year)=1.01, 95% credible interval 1.00–1.01; p=0.030) in the prevalence of total CDH over time but there was no significant increase for isolated cases (ie, CDH cases that did not occur with any other congenital anomaly). There was significant variation in total and isolated CDH prevalence between registers. The proportion of cases that survived to 1 week was 69.3% (1392 cases) for total CDH cases and 72.7% (1107) for isolated cases. Conclusions This large population-based study found an increase in total CDH prevalence over time. CDH prevalence also varied significantly according to geographical location. No significant association was found with maternal age.

Repair of mitochondrial DNA damage induced by bleomycin in human cells

Damage to mitochondrial DNA (mtDNA) has recently been associated with a variety of human diseases including cancer, diabetes mellitus, and aging. The mechanisms by which the mitochondria respond to DNA damage are of prime importance in understanding how damage can persist and cause disease. Here we demonstrate the repair of mitochondrial DNA damage induced by the naturally occurring, radiomimetic drug bleomycin. WI-38 cells were first permeabilized using 20 micrograms/ml lysophosphatidylcholine in order to increase the intracellular concentration of bleomycin. Dose response studies with the permeabilized cells showed that a concentration of 5 micrograms/ml bleomycin given for 30 min caused sufficient DNA damage for repair studies. Following treatment with this concentration of bleomycin, repair of mtDNA damage was found to be about 80% by 2 h. However, after 4 h no additional repair was observed. The results indicate that there is an efficient DNA repair system in human mitochondria for some types of damage caused by bleomycin. However, there is a component of damage caused by this agent that either is not repaired or is removed at a much slower rate.

Myopathy in Marinesco-Sjogren Syndrome

Progressive muscular weakness, hypotonia and atrophy are among the cardinal signs of the Marinesco-Sjogren syndrome but have not been extensively investigated. Our study focused on 6 related patients who are members of an inbred population. Muscle biopsies revealed myopathic alterations with variation of fiber size, rounding, degeneration and regeneration of fibers, internalization of nuclei and endomysial fat and fibrosis. Most patients had elevated serum creatine kinase levels. One patient revealed endstage neuromuscular disease and had normal serum creatine kinase levels. Of particular interest was the finding of conspicuous myopathy in 2 young children. Thus far, it has not been appreciated that myopathy represents an early sign of the Marinesco-Sjogren syndrome.

DiGeorge syndrome associated with combined immunodeficiency

An infant with DiGeorge syndrome—complete with typical facies, neonatal hypocalcemic tetany, right-sided aortic arch, cardiac defects, and absent thymic shadow—had immunologic deficiencies of both cell-mediated and humoral compartments. The cell-mediated deficit was partial in that in vitro lymphocyte responses to phytohemagglutinin were absent while responses to allogeneic cells in one-way mixed leukocyte cultures were normal after three weeks of age. Humoral immune deficiency was manifested by low or absent immunoglobulin levels, failure to produce antibodies following repeated immunization with killed polio vaccine, typhoid-paratyphoid, and peneumococcal polysaccharide antigen, and lack of in vitro lymphocyte responses to pokeweed mitogen. These studies suggest a diagnosis of “DiGeorge variant.” Thymus transplantation at 45 days of age was followed by full recovery of lymphocyte responses to phytohemagglutinin and pokeweed mitogen, an increase of immunoglobulin levels to within normal ranges, and rejection of two skin grafts. These changes were accompanied by the appearance of normal numbers of small lymphocytes and plasma cells, in bone marrow and intestinal lamina propria, respectively. The effect of thymus transplantation on the immunologic recovery in this patient cannot be determined.

Cytological analyses of a 14p+variant by means of N-banding and combinations of silver staining and chromosome bandings

SummaryAn inherited human karyological variant (14p+) has been studied with a number of cytochemical techniques. The short arm of this variant chromosome 14 is nearly as long as the long arm, giving the chromosome a submetacentric to metacentric appearance. In conventionally Giemsa-stained preparations, a maximum of three secondary constrictions can be observed in the marker arm. The secondary constrictions are silver-positive in Ag-NOR preparations. However, the entire arm stains deeply in N-banded preparations. The 14p+ arm also Q-negative, C-negative, G-negative, and R-positive with an almost homogeneous texture. The difference between N-banding and silver staining is interpreted as the result of gene activities of the ribosomal cistrons.