Juan C. Llerena

Prenatal exposure to misoprostol and vascular disruption defects: A case-control study

Prenatal exposure to misoprostol has been associated with Moebius and limb defects. Vascular disruption has been proposed as the mechanism for these teratogenic effects. The present study is a multicenter, case-control study that was designed to compare the frequency of prenatal misoprostol use between mothers of Brazilian children diagnosed with vascular disruption defects and matched control mothers of children diagnosed with other types of defects. A total of 93 cases and 279 controls were recruited in eight participating centers. Prenatal exposure was identified in 32 infants diagnosed with vascular disruption defects (34.4%) compared with only 12 (4.3%) in the control group (P<0.0000001). Our data suggest that prenatal exposure to misoprostol is associated to the occurrence of vascular disruption defects in the newborns.

Mucopolysaccharidosis I, II, and VI: brief review and guidelines for treatment

Mucopolysaccharidoses (MPS) are rare genetic diseases caused by the deficiency of one of the lysosomal enzymes involved in the glycosaminoglycan (GAG) breakdown pathway. This metabolic block leads to the accumulation of GAG in various organs and tissues of the affected patients, resulting in a multisystemic clinical picture, sometimes including cognitive impairment. Until the beginning of the XXI century, treatment was mainly supportive. Bone marrow transplantation improved the natural course of the disease in some types of MPS, but the morbidity and mortality restricted its use to selected cases. The identification of the genes involved, the new molecular biology tools and the availability of animal models made it possible to develop specific enzyme replacement therapies (ERT) for these diseases. At present, a great number of Brazilian medical centers from all regions of the country have experience with ERT for MPS I, II, and VI, acquired not only through patient treatment but also in clinical trials. Taking the three types of MPS together, over 200 patients have been treated with ERT in our country. This document summarizes the experience of the professionals involved, along with the data available in the international literature, bringing together and harmonizing the information available on the management of these severe and progressive diseases, thus disclosing new prospects for Brazilian patients affected by these conditions.

Atenção aos defeitos congênitos no Brasil: panorama atual

Birth defects have increased progressively in Brazil, shifting from the fifth to the second cause of infant mortality from 1980 to 2000, thus highlighting the need for specific health policy strategies. Some governmental and nongovernmental actions related to birth defects in Brazil include information services on teratogenic agents and inborn errors of metabolism, monitoring of birth defects, neonatal screening and treatment of some genetic diseases, and rubella immunization. In addition, flour fortification with folic acid for prevention of certain birth defects has begun recently. Despite the importance of such initiatives, it is still difficult to view birth defects from a comprehensive perspective. A specific national policy on birth defects must be formulated. Active participation is needed by the Ministry of Health, using existing genetic services as the backbone, in order to develop a regionalized, hierarchical, and functional network related to birth defects in Brazil.

Microdeletion and Microduplication Syndromes

The widespread use of whole genome analysis based on array comparative genomic hybridization in diagnostics and research has led to a continuously growing number of microdeletion and microduplication syndromes (MMSs) connected to certain phenotypes. These MMSs also include increasing instances in which the critical region can be reciprocally deleted or duplicated. This review catalogues the currently known MMSs and the corresponding critical regions including phenotypic consequences. Besides the pathogenic pathways leading to such rearrangements, the different detection methods and their limitations are discussed. Finally, the databases available for distinguishing between reported benign or pathogenic copy number alterations are highlighted. Overall, a review of MMSs that previously were also denoted “genomic disorders” or “contiguous gene syndromes” is given.

Intrathecal administration of recombinant human N-acetylgalactosamine 4-sulfatase to a MPS VI patient with pachymeningitis cervicalis.

In mucopolysaccharidosis VI, or Maroteaux-Lamy syndrome, deficiency of N-acetylgalactosamine 4-sulfatase leads to storage of glycosaminoglycans (GAGs) and MPS VI patients often develop spinal cord compression during the course of the disease due to GAG storage within the cervical meninges, requiring neurosurgical intervention, as intravenous (IV) enzyme replacement therapy (ERT) is not expected to cross the blood-brain barrier. We report the use of intrathecal (IT) recombinant human N-acetylgalactosamine 4-sulfatase (arylsulfatase B, or ASB) in a MPS VI child with spinal cord compression whose parents initially refused the surgical treatment. Assessments were performed at baseline, with clinical, neurological and biochemical evaluations, urodynamic studies and MRI of the CNS. Changes on these parameters were evaluated after IT infusions of ASB administered monthly via lumbar puncture (LP) in a IV ERT naive patient. To our knowledge, this was the first MPS VI patient who received IT ERT. Despite significant urodynamic improvement and some neurological amelioration, the patient developed worsening of walking capacity. After IV ERT was started, the patient presented with a generalized hypotonia and a life-saving surgical fixation of the neck was then performed. The results observed on this MPS VI patient suggest that instability of the cervical vertebrae could be unmasked by IV ERT as joint storage is reduced, and the decrease in neck stiffness and stability could confound the expected improvement of SCC manifestations following IT ERT. The study of further patients, if possible in a clinical trial setting, is needed to evaluate the potential of a non-surgical IT ERT treatment of SCC for MPS VI.

Novel mutations and polymorphisms in the Fanconi anemia group C gene

Fanconi anemia (FA) is an autosomal recessive disorder associated with hypersensitivity to DNA cross‐linking agents and bone marrow failure. At least four complementation groups have been defined, and the FA group C gene (FAC) has been cloned. We have screened 76 unrelated FA patients of diverse ethnic and geographic origins and from unknown complementation groups for mutations in the FAC gene either by chemical cleavage mismatch analysis or by single‐strand conformational polymorphism (SSCP). Five mutations were detected in four patients (5.3%), including two novel mutations (W22X and L496R). Nine polymorphisms were detected, seven of which have not been described previously (663A → G, L190F, IVS6 + 30C → T, 1312V, V449M, Q465R, and 1974G → A). Six of the nine polymorphisms occurred in patients or controls from the Tswana or Sotho chiefdoms of South Africa and were not found in 50 unrelated European controls. Restriction site assays were established for all 8 pathogenic mutations identified in the FAC gene to date and used to screen a total of 94 unrelated FA patients. This identified only one other group C patient, who was homozygous for the mutation IVS4 + 4A → T. This study indicates that the proportion of FA patients from complementation group C is generally likely to be less than 10%. Guidelines for the selection of FA patients for FAC mutation screening are proposed.

Identification of novel mutations in SHH and ZIC2 in a South American (ECLAMC) population with holoprosencephaly

Abstract. Holoprosencephaly (HPE) is genetically heterogeneous with four genes, SIX3, SHH, TGIF, and ZIC2 that have been identified to date and that are altered in 12% of patients. To analyze this prevalence in a South American population-based sample (57 HPE cases in 244,511 live and still births or 1 in 4300), we performed a mutational study of these genes in 30 unrelated children (26 newborns and 4 non-newborns) with HPE being ascertained by ECLAMC (Latin American Collaborative Study of Congenital Malformations). We identified three novel mutations: two were missense mutations of the SHH gene (Cys183→Phe; His140→Pro); the third mutation was a 2-bp deletion in the zinc-finger region of the ZIC2 gene. These molecular results explained 8% (2/26 newborn samples) of the HPE cases in this South American population-based sample, a proportion similar to our previously published data from a collection of cases.

Atenção aos defeitos congênitos no Brasil: características do atendimento e propostas para formulação de políticas públicas em genética clínica

The impact of birth defects in Brazil has increased steadily, indicating the need for specific health policy strategies. Despite the close relationship between clinical genetics and management of birth defects, less than 30% of the total demand is currently met by existing genetic services. The main problems are: difficult access to genetic services, services highly concentrated in the South and Southeast regions of the country, and insufficient laboratory support. With the aim of improving management of birth defects, a specific national policy coordinated by the Ministry of Health needs to be developed. The main goal of such a policy should be the organization of a functional integrated genetics network, in addition to rational use of resources and enhanced coverage. In order to formalize a national laboratory network, sample shipping and billing mechanisms must be created. Birth defect prevention, education for the medical community and general population, and solid epidemiological data collection are strongly recommended as complementary measures. If such recommendations are implemented, it could be possible to organize a network for management of birth defects in Brazil that is regionalized, hierarchical, functional, and democratic as well.

Defeitos congênitos no Município do Rio de Janeiro, Brasil: uma avaliação através do SINASC (2000-2004)

To evaluate the occurrence of birth defects in the city of Rio de Janeiro, Brazil, using the Live Birth Information System (SINASC), we performed a cross-sectional study on all live newborns with birth defects from January 1, 2000, to December 31, 2004. The variables referred to birth defects (presence and system affected), type of health service, mothers, gestations, live births, and deliveries. Prevalence of birth defects was 83/10,000 live births. The most frequent birth defects involved the musculoskeletal system, central nervous system, cleft lip and palate, and chromosomal anomalies. The majority of cases were born in public (municipal) and private maternity hospitals, with the highest prevalence in the Fernandes Figueira Insitute, Oswaldo Cruz Foundation. Older women and those with less schooling had more live born infants with birth defects. The proportion of reports with missing information was high, reaching 21% in some institutions. Wider dissemination of SINASC data on birth defects should be encouraged. Reliability studies are recommended for better use of these reports.

Confiabilidade das informações das declarações de nascido vivo com registro de defeitos congênitos no Município do Rio de Janeiro, Brasil, 2004

This study assessed the reliability of birth certificate data related to birth defects in Brazils Live Birth Information System (SINASC). We selected 24 maternity hospitals in the Unified National Health System (SUS) and compared the reports of birth defects from birth certificates with medical records of mothers and live born infants in the city of Rio de Janeiro for the year 2004. After transposing the data to a specific form, the birth defects were coded by types and organ systems and compared to the SINASC data. The most commonly affected organs involved the central nervous and musculoskeletal systems. Agreement was more than 50% for the digestive, genitourinary, and musculoskeletal systems and chromosomal anomalies. Prevalence-adjusted kappa varied according to 2 or 3-digit ICD-10 analysis, with better results for the musculoskeletal, digestive, and genitourinary systems and congenital anomalies, and worse for the central nervous and cardio-circulatory systems, eye, neck, and ear malformations, and cleft lip and palate. The results were unsatisfactory, suggesting the need for more investments to train the persons responsible for completing birth certificates in maternity hospitals and develop a model for coding birth defects on these documents.