Multisystem Abnormalities Research Articles

Blount disease in a case of Prader-Willi syndrome: why is it not as prevalent as in obesity without Prader-Willi syndrome?

Prader-Willi syndrome (PWS) is a genetic disorder causing multisystem abnormalities with obesity. Obesity is a well established cause of Blount disease. A 7-year-old girl with PWS presented with genu varum of the left knee with deformity of the proximal medial tibial condyle, which was consistent with Blount disease. A lateral physeal stapling and subsequent osteotomy for the left proximal tibia and fibula were performed with improved anatomical alignment. Blount disease has not been reported in the literature in association with PWS despite excessive obesity.

Neonatal Graves' Disease Associated With Severe Metabolic Abnormalities

Neonatal Graves' disease is a rare condition that is sometimes associated with multisystem abnormalities that can mimic infection or inborn errors of metabolism. Here we describe the cases of 2 infants who had serious metabolic derangements including conjugated hyperbilirubinemia and hyperammonemia.

Ophthalmoplegia as the presenting muscle-related manifestation of myotonic dystrophy

Myotonic dystrophy type 1 (DM1) is a genetic disorder caused by expanded CTG repeats within the 3' untranslated region of the dystrophia myotonia protein kinase (DMPK) gene on chromosome 19. Diplopia is rare in this disease and has only been reported in patients with diffuse neuromuscular disorders. We report here on the case of a 58-year-old woman in whom ophthalmoplegia was the first neuromuscular manifestation of DM1 and led to the diagnosis. Among the multisystem abnormalities associated with DM1, muscle-related symptoms are prominent, and usually involve the facial and neck muscles early on in the disease. This case provides additional evidence of oculomotor muscle involvement in DM1. DM1 should, therefore, be considered during the diagnostic workup of any unexplained ophthalmoplegia of muscle origin, especially if there has been a previous history of cataract, even in the absence of typical muscle-related features.

Molecular Basis for Zinc Transporter 1 Action as an Endogenous Inhibitor of L-type Calcium Channels

The L-type calcium channel (LTCC) has a variety of physiological roles that are critical for the proper function of many cell types and organs. Recently, a member of the zinc-regulating family of proteins, ZnT-1, was recognized as an endogenous inhibitor of the LTCC, but its mechanism of action has not been elucidated. In the present study, using two-electrode voltage clamp recordings in Xenopus oocytes, we demonstrate that ZnT-1-mediated inhibition of the LTCC critically depends on the presence of the LTCC regulatory beta-subunit. Moreover, the ZnT-1-induced inhibition of the LTCC current is also abolished by excess levels of the beta-subunit. An interaction between ZnT-1 and the beta-subunit, as demonstrated by co-immunoprecipitation and by fluorescence resonance energy transfer, is consistent with this result. Using surface biotinylation and total internal reflection fluorescence microscopy in HEK293 cells, we show a ZnT-1-dependent decrease in the surface expression of the pore-forming alpha(1)-subunit of the LTCC. Similarly, a decrease in the surface expression of the alpha(1)-subunit is observed following up-regulation of the expression of endogenous ZnT-1 in rapidly paced cultured cardiomyocytes. We conclude that ZnT-1-mediated inhibition of the LTCC is mediated through a functional interaction of ZnT-1 with the LTCC beta-subunit and that it involves a decrease in the trafficking of the LTCC alpha(1)-subunit to the surface membrane.

SMC1Aexpression and mechanism of pathogenicity in probands with X-Linked Cornelia de Lange syndrome

Cornelia de Lange Syndrome (CdLS) is a dominantly inherited heterogeneous genetic disorder with multisystem abnormalities. Sixty percent of probands with CdLS have heterozygous mutations in the Nipped-B-like (NIPBL) gene, 5% have mutations in the SMC1A gene, and one proband was found to have a mutation in the SMC3 gene. Cohesin is a multisubunit complex consisting of a SMC1A and SMC3 heterodimer and two non-SMC subunits. SMC1A is located on the human X chromosome and is reported to escape X inactivation. Twenty-nine unrelated CdLS probands with 21 unique SMC1A mutations have been identified including seven males. All mutations identified to date are either missense or small deletions, with all presumably preserving the protein open reading frame. Both wild-type and mutant alleles are expressed. Females quantitatively express twice the amount of SMC1A mRNA compared to males. The transcriptional profiling of 23 selected genes is different in SMC1A mutant probands, controls, and NIPBL mutant probands. These results suggest that mechanistically SMC1A-related CdLS is not due to altered levels of the SMC1A transcript, but rather that the mutant proteins maintain a residual function in males and enact a dominant negative effect in females.

Dosage effects of cohesin regulatory factor PDS5 on mammalian development: implications for cohesinopathies.

Cornelia de Lange syndrome (CdLS), a disorder caused by mutations in cohesion proteins, is characterized by multisystem developmental abnormalities. PDS5, a cohesion protein, is important for proper chromosome segregation in lower organisms and has two homologues in vertebrates (PDS5A and PDS5B). Pds5B mutant mice have developmental abnormalities resembling CdLS; however the role of Pds5A in mammals and the association of PDS5 proteins with CdLS are unknown. To delineate genetic interactions between Pds5A and Pds5B and explore mechanisms underlying phenotypic variability, we generated Pds5A-deficient mice. Curiously, these mice exhibit multiple abnormalities that were previously observed in Pds5B-deficient mice, including cleft palate, skeletal patterning defects, growth retardation, congenital heart defects and delayed migration of enteric neuron precursors. They also frequently display renal agenesis, an abnormality not observed in Pds5B−/− mice. While Pds5A−/− and Pds5B−/− mice die at birth, embryos harboring 3 mutant Pds5 alleles die between E11.5 and E12.5 most likely of heart failure, indicating that total Pds5 gene dosage is critical for normal development. In addition, characterization of these compound homozygous-heterozygous mice revealed a severe abnormality in lens formation that does not occur in either Pds5A−/− or Pds5B−/− mice. We further identified a functional missense mutation (R1292Q) in the PDS5B DNA-binding domain in a familial case of CdLS, in which affected individuals also develop megacolon. This study shows that PDS5A and PDS5B functions other than those involving chromosomal dynamics are important for normal development, highlights the sensitivity of key developmental processes on PDS5 signaling, and provides mechanistic insights into how PDS5 mutations may lead to CdLS.

Ciliary Abnormalities Due to Defects in the Retrograde Transport Protein DYNC2H1 in Short-Rib Polydactyly Syndrome

The short-rib polydactyly (SRP) syndromes are a heterogeneous group of perinatal lethal skeletal disorders with polydactyly and multisystem organ abnormalities. Homozygosity by descent mapping in a consanguineous SRP family identified a genomic region that contained DYNC2H1, a cytoplasmic dynein involved in retrograde transport in the cilium. Affected individuals in the family were homozygous for an exon 12 missense mutation that predicted the amino acid substitution R587C. Compound heterozygosity for one missense and one null mutation was identified in two additional nonconsanguineous SRP families. Cultured chondrocytes from affected individuals showed morphologically abnormal, shortened cilia. In addition, the chondrocytes showed abnormal cytoskeletal microtubule architecture, implicating an altered microtubule network as part of the disease process. These findings establish SRP as a cilia disorder and demonstrate that DYNC2H1 is essential for skeletogenesis and growth.

Clinical and genetic heterogeneity in keratosis follicularis spinulosa decalvans

Keratosis follicularis spinulosa decalvans (KFSD) is an uncommon genodermatosis mainly characterized by follicular hyperkeratosis, progressive cicatricial alopecia and photophobia. Although an excess of affected males and linkage studies strongly suggest an X-linked pattern of inheritance, an apparently rarer autosomal dominant form with prominent follicular inflammation has also been postulated. We report on a three-generation family with five affected individuals and male-to-male transmission. In addition to widespread keratosis pilaris, cicatricial alopecia and eye involvement, our patients show diffuse facial erythema, recurrent folliculitis, enamel hypoplasia, and thickened nails. A literature review of the last 50 years identified 43 additional KFSD cases. X-linked inheritance is demonstrated in two pedigrees by linkage studies and suspected in five. An autosomal dominant pattern is confirmed in three families, including ours, by male-to-male transmission and considered likely in four. Marked facial erythema, extensive folliculitis, onychodystrophy and multiple caries are frequently reported in the autosomal dominant variant, while palmo-plantar keratoderma and early onset seem more typical of the X-linked form. Moreover, three sporadic male patients showing additional multisystemic abnormalities might be explained by an X-linked contiguous-gene syndrome.

Trichothiodystrophy: a systematic review of 112 published cases characterises a wide spectrum of clinical manifestations

Trichothiodystrophy (TTD) is a rare, autosomal recessive disease, characterised by brittle, sulfur deficient hair and multisystem abnormalities. A systematic literature review identified 112 patients ranging from 12 weeks to 47...

Gene Identification for the cblD Defect of Vitamin B12Metabolism

Vitamin B12 (cobalamin) is an essential cofactor in several metabolic pathways. Intracellular conversion of cobalamin to its two coenzymes, adenosylcobalamin in mitochondria and methylcobalamin in the cytoplasm, is necessary for the homeostasis of methylmalonic acid and homocysteine. Nine defects of intracellular cobalamin metabolism have been defined by means of somatic complementation analysis. One of these defects, the cblD defect, can cause isolated methylmalonic aciduria, isolated homocystinuria, or both. Affected persons present with multisystem clinical abnormalities, including developmental, hematologic, neurologic, and metabolic findings. The gene responsible for the cblD defect has not been identified. We studied seven patients with the cblD defect, and skin fibroblasts from each were investigated in cell culture. Microcell-mediated chromosome transfer and refined genetic mapping were used to localize the responsible gene. This gene was transfected into cblD fibroblasts to test for the rescue of adenosylcobalamin and methylcobalamin synthesis. The cblD gene was localized to human chromosome 2q23.2, and a candidate gene, designated MMADHC (methylmalonic aciduria, cblD type, and homocystinuria), was identified in this region. Transfection of wild-type MMADHC rescued the cellular phenotype, and the functional importance of mutant alleles was shown by means of transfection with mutant constructs. The predicted MMADHC protein has sequence homology with a bacterial ATP-binding cassette transporter and contains a putative cobalamin binding motif and a putative mitochondrial targeting sequence. Mutations in a gene we designated MMADHC are responsible for the cblD defect in vitamin B12 metabolism. Various mutations are associated with each of the three biochemical phenotypes of the disorder.

Dyskeratosis congenita: Advances in the understanding of the telomerase defect and the role of stem cell transplantation

DC is a multisystem bone marrow failure syndrome exhibiting marked clinical and genetic heterogeneity. X-linked, autosomal dominant and autosomal recessive subtypes are recognized. The gene mutated in X-linked DC (DKC1) encodes a highly conserved nucleolar protein called dyskerin. Dyskerin associates with the H/ACA motif class of small nucleolar RNAs in small nucleolar ribonucleoprotein particles that are important in guiding the conversion of uracil to pseudouracil during the maturation of ribosomal RNA. Dyskerin also associates with the TERC, which is important in the maintenance of telomeres. Mutations in TERC have been identified in patients with autosomal dominant DC and in a subset of patients with aplastic anemia and myelodysplasia. Recently, heterozygous mutations in TERT have been found in some patients with autosomal dominant DC and aplastic anemia. Additionally, patients with the severe multisystem disorder, Hoyeraal-Hreidarsson syndrome, have been found to have DKC1 mutations. Collectively, these observations have demonstrated that classical DC, Hoyeraal-Hreidarsson syndrome and a subset of aplastic anemia are due to a primary defect in telomerase. The critical role of telomeres and telomerase in humans is seen in the multisystem abnormalities found in these patients, including the increased incidence of malignancy. As bone marrow failure is the principal cause of death, conventional allografts have been attempted with limited success due to the high rate of pulmonary and endothelial complications. However, outcomes have improved with the use of non-myeloablative protocols, although the follow up is too short to evaluate long term toxicity and the natural course of the disease and it may be that correction of the telomerase defect is essential for the treatment of these patients.

Chorea associated with antiphospholipid antibodies in a patient with Kabuki syndrome

Kabuki syndrome, OMIM 147920 (KS) is a disorder characterized by multi-system abnormalities. These include physical, neurological, endocrine, and autoimmune abnormalities. Multiple autoimmune abnormalities are described in KS such as immune thrombocytopenic purpura (ITP), vitiligo, thyroiditis, hemolytic anemia, and hypogammaglobulinemia. In this report, we describe a patient with KS with sudden onset chorea associated with the presence of anti-phospholipid antibodies (aPLs) in the serum. Chorea in the presence of aPLs has been well described in the literature both in the presence and absence of antiphospholipid syndrome (APS) and systemic lupus erythematosus (SLE). This report of APL in a patient with KS adds to the list of autoimmune disorders seen in patients with KS and also strengthens the hypothesis that patients with this syndrome have an increased incidence of immune dysregulation.

A review of neurocognitive and behavioral profiles associated with 22q11 deletion syndrome: Implications for clinical evaluation and treatment

22q11 deletion syndrome (22q11DS) is a chromosomal disorder that results in variable multisystem abnormalities, including conotruncal cardiac malformations, aplasia or hypoplasia of the thymus and/or parathyroid glands, immunodeficiency, dysmorphic facial features, and cleft palate and other nasopharyngeal and dental anomalies. Individuals with 22q11DS also exhibit cognitive and behavioral difficulties, including delayed motor and speech-language development, mental retardation, low academic achievement, impaired spatial reasoning, poor attentional and executive functioning, attention-deficit hyperactivity disorder, autism spectrum disorders, mood disorders, and/or schizophrenia spectrum disorders. Interventions should be designed based on the results of periodic developmental and neuropsychological assessments and psychiatric screening. Future research should focus on understanding deletion-related gene-environment interactions and their effects on developmental and behavioral outcomes, identifying neurodegenerative processes in 22q11DS, and developing preventive models of behavioral and psychopharmacologic treatment.

Barrier Dysfunction and Pathogenesis of Neutral Lipid Storage Disease with Ichthyosis (Chanarin–Dorfman Syndrome)

Neutral lipid storage disease with ichthyosis (NLSDI; Chanarin-Dorfman syndrome) is an ichthyosiform syndrome, often associated with mutations in a lipid hydrolase, CGI-58. The presence of oil red O-positive, neutral lipid droplets in tissue biopsies, and/or in leukocytes on blood smears, coupled with a constellation of multisystem abnormalities and a pruritic ichthyosiform erythroderma, are together diagnostic of NLSDI. We investigated the pathogenesis of the ichthyosiform erythroderma in patients from three unrelated kindreds with a clinical diagnosis of NLSDI. Basal permeability barrier function and stratum corneum (SC) integrity were abnormal, but barrier recovery rates were faster than normal, as in atopic dermatitis. The basal barrier abnormality was linked to the secretion of lipid micro-inclusions, first segregated within lamellar bodies (LB), which then form a non-lamellar phase within the SC interstices, shown by combined ruthenium tetroxide post-fixation and lipid-retaining resin-white embedding. With colloidal lanthanum nitrate perfusion, excess water/solute movement was restricted to the SC interstices, and further localized to non-lamellar domains. Phase separation of excess stored lipid provides a unifying pathogenic mechanism not only for NLSDI, but also in several other inherited ichthyosiform disorders of lipid metabolism, such as recessive X-linked ichthyosis and type 2 Gaucher's disease.

Acute Myelomonocytic Leukemia in a Boy With LEOPARD Syndrome (PTPN11 Gene Mutation Positive)

The LEOPARD syndrome is a complex of multisystemic congenital abnormalities characterized by lentiginosis, electrocardiographic conduction abnormalities, ocular hypertelorism, pulmonary stenosis, abnormalities of genitalia, retardation of growth, and deafness (sensorineural). Mutations in PTPN11, a gene encoding the protein tyrosine phosphatase SHP-2 located on chromosome 12q24.1, have been identified in 88% of patients with LEOPARD syndrome. A missense mutation (836-->G; Tyr279Cys) in exon 7 of PTPN11 gene was identified in this patient and his mother with LEOPARD syndrome. This mutation is one of the two recurrent mutations most often associated with the syndrome. Leukemia has not previously been reported in patients with LEOPARD syndrome. The authors describe a 13-year-old boy diagnosed with both LEOPARD syndrome and acute myelomonocytic leukemia (AML-M4).

Estimation of the Genetic Risks of Exposure to Ionizing Radiation in Humans: Current Status and Emerging Perspectives

The 2001 report of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) on ;Hereditary effects of radiation' incorporates two important concepts that have emerged from advances in radiation genetics and molecular biology: (a) most radiation-induced mutations are DNA deletions, often encompassing multiple genes; however, because of structural and functional constraints, only a proportion of induced deletions may be compatible with viability and hence recoverable in the progeny and (b) viability-compatible DNA deletions induced in human germ cells are more likely to cause multi-system developmental abnormalities rather than single-gene diseases. The work reported in this paper pursues these concepts further: it examines how mechanistic insights gained from studies of repair of radiation-induced DNA double-strand breaks (DSBs) in mammalian somatic cells and from those on the origin of deletions in human genomic disorders can be extended to germ cells the aim being the development of a framework to predict regions of the human genome that may be susceptible to radiation-induced deletions. A critical analysis of the available information permits the hypothesis that in stem cell spermatogonia, most induced deletions may arise via the non-homologous end joining (NHEJ) mechanism of DSB repair whereas in irradiated oocytes, the main mechanism is likely to be non-allelic homologous recombination (NAHR) between misaligned region-specific segmental duplications that are present in the genome (NAHR is an error-prone form of homologous recombination repair). Should this hypothesis turn out to be valid, then it is possible to build on the structural and functional aspects of genomic knowledge to devise strategies to predict where in the genome deletions may be induced by radiation, their extent and their potential phenotypes.

Hemolytic Uraemic Syndrome Associated with Pregnancy

Hemolytic uraemic syndrome (HUS) and thrombotic thrombocytopenic purpura (TTP) are described as acute syndromes with multisystem abnormalities and pentad of thrombocytopenia, microangiopathic hemolysis, neurological symptoms, renal impairment and fever. Both diseases were believed to form a continuum of the same disease, but recently it was found, that they were having a different pathophysiology, as TTP patients have a deficiency in von wilbrand factor (vWF) cleavage protease. When renal involvement is severe with little or no neurological manifestation, this microangiopathy is termed as haemolytic-uraemic syndrome. If the hemolytic uraemic syndrome is not associated with diarrhoea, it is called Dnegative or atypical HUS. This subdivision is of etiological and prognostic importance. TTP-HUS is associated with high maternal and fetal morbidity and mortality. Treatment of these syndromes differs from syndrome of hemolysis with elevated liver enzymes (HE LLP syndrome) and acute fatty liver of pregnancy hence accurate diagnosis is important for optimal therapy. Plasma transfusion and plasmapheresis have revolutionized management of TTP and HUS by increasing survival 80% to 90%. Here we are reporting a case of D-negative hemolytic uraemic syndrome associated with pregnancy causing intrauterine fetal death. Diagnosis made on clinical and hematological findings, successfully treated by plasmapheresis with residual maternal renal impairment. We are presenting this case, as it is rare disorder associated with high mortality and morbidity, to increase awareness about disease, its diagnosis and management.

Foetal alcohol syndrome: a dental and skeletal age analysis of patients and controls

Foetal alcohol syndrome (FAS) consists of multisystem abnormalities and is caused by the excessive intake of alcohol during pregnancy. The teratogenic effect of alcohol on the human foetus has now been established beyond reasonable doubt and FAS is one of the most important human teratogenic conditions known today. The purpose of this study was to assess the dental age (DA) and skeletal age (SA) of children with FAS and compare them with matched controls. The samples of 90 children diagnosed with FAS and 90 controls were matched for age, gender, and social class. The mean chronological age (CA) of the FAS subjects was 8.95 years, with the controls slightly older at 9.04 years. This difference was not significant. Dental maturity was determined by assessing the stage of tooth formation and SA assessment was made from hand-wrist radiographs for the patients and controls by assigning a SA and comparing it with standard plates. The means and standard deviations of CA and DA for the stages of calcification were calculated and the Pearson ranked order correlation coefficient was applied to measure the associations between skeletal maturity indicators and DA. t-tests were used to test for group differences between independent groups, and paired t-tests to determine paired group differences. This study provided evidence of a positive association between DA and SA in both the FAS children and the controls. The data suggest that both DA and SA may be a reflection of general somatic growth. It must be acknowledged that growth of individuals is often irregular, when any norms of development based on central tendencies and variabilities of healthy children are applied. Some aspects of growth and development for healthy children may show a variable pattern of growth. Therefore, correlation of these aspects of growth and development will often not show the degree of correlation that theoretically exists between different areas of growth and development. A more complete appraisal of the entire skeleton and an evaluation of the entire dentition, rather than just the mandibular teeth, might improve the correlation between the variables.

Foetal alcohol syndrome: a cephalometric analysis of patients and controls

Foetal alcohol syndrome (FAS) consists of multi-system abnormalities and is caused by the excessive intake of alcohol during pregnancy. The teratogenic effect of alcohol on the human foetus has now been established beyond reasonable doubt and FAS is the most important human teratogenic condition known today. The purpose of this study was to analyse the craniofacial parameters of children with FAS and compare them with matched controls. Ninety children diagnosed with FAS (45 males, 45 females) and 90 controls were matched for age, gender, and social class. The mean age of the FAS children was 8.9 years with the controls slightly older at 9.1 years. This age difference was not significant (P = 0.34). A standard lateral cephalometric radiograph of each subject was taken. The radiographs were digitized for 20 linear and 17 angular measurements. These 37 variables were formulated to assess the size, shape, and relative position of three craniofacial complexes: (1) the cranial base, (2) midface, and (3) mandible. In addition, nine variables were computed to compare the soft tissue profiles. The study showed that measurements related to face height and mandibular size appear to be the most important features when distinguishing FAS children. Overall, the FAS children in the present study presented with vertically and horizontally underdeveloped maxillae, together with features of long face syndrome with large gonial angles and a short ramus in relation to total face height. There was also a tendency for the development of an anterior open bite, which appears to be compensated for by an increase in the vertical dimension of the anterior alveolar process to bring the incisor teeth into occlusion. The latter adaptation occurred mainly in the mandible.

67 Human Bauplan Anomalies

The german term Bauplan means body-plan, but captures also the idea of the architectural constraints existing in such a functional design. There are only a few animal Bauplane, and each phylum is characterized by one of them. Major Bauplan's modifications within a taxon are not tolerated. The concept is common between the zoologists, but usually is not employed in human pathology. Our hypothesis is that an approach to the birth defects in terms of basic body-plan results in a better understanding of the human ontogenetic and phylogenetic development. We observed 30 interrupted pregnancies owing to severe structural fetal malformations. A pathological study was performed in all the fetuses. We found the following syndromes and anomalies: Meckel-Gruber syndrome 1; Cantrell's pentalogy 1; Ivemark syndrome 1; Omphalocele-radial hypoplasia complex 1; Triploid syndrome 1; Malformative associations including encephalic anomalies 3; SNC isolated abnormalities (comprehensive of 10 neural tube defects) 16; Gastroschisis 1; Complex cardiac anomalies 3; Kidney defects, including bilateral renal agenesis 2; According to our study, three major Bauplan defects are detectable in the aborted fetuses. They are concerning with: (1) cephalization, (2) laterality, (3) closure of the fetal body surface, and all of them are related to a midline pathology. These results are in agreement with the belonging of our species to the chordates deuterostomata and suggest that the human Bauplan begins to appear in the early blastogenesis, when the nothocord appears and neurulation occurs. In this period the embryo seems to act as a single morphogenetic unit, so that blastogenetic defects are frequently multisystem abnormalities. 1/3 of the fetuses presented complex malformative disorders. Besides being a source for studies of evolutionary developmental biology (Evo-Devo), the investigation on human blastogenesis and organogenesis through an oriented evaluation of the birth defects could have in the future unexpected therapeutic relevance.