Subtotal amelia in a child with autosomal recessive hypohidrotic ectodermal dysplasia.
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We report an inbred Tunisian family, in which the proband manifested signs of hypohidrotic ectodermal dysplasia, subtotal amelia, scoliosis and left renal agenesis. Two other family members had the full clinical criteria of hypohidrotic ectodermal dysplasia, characterized by deficient sweat glands, hypodontia, hypoplasia of the mucous glands, and fine hair. Nine family subjects had variable clinical expression of the disorder. (+info)
Inactivating mutations in ESCO2 cause SC phocomelia and Roberts syndrome: no phenotype-genotype correlation.
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The rare, autosomal recessive Roberts syndrome (RBS) is characterized by tetraphocomelia, profound growth deficiency of prenatal onset, craniofacial anomalies, microcephaly, and mental deficiency. SC phocomelia (SC) has a milder phenotype, with a lesser degree of limb reduction and with survival to adulthood. Since heterochromatin repulsion (HR) is characteristic for both disorders and is not complemented in somatic-cell hybrids, it has been hypothesized that the disorders are allelic. Recently, mutations in ESCO2 (establishment of cohesion 1 homolog 2) on 8p21.1 have been reported in RBS. To determine whether ESCO2 mutations are also responsible for SC, we studied three families with SC and two families in which variable degrees of limb and craniofacial abnormalities, detected by fetal ultrasound, led to pregnancy terminations. All cases were positive for HR. We identified seven novel mutations in exons 3-8 of ESCO2. In two families, affected individuals were homozygous--for a 5-nucleotide deletion in one family and a splice-site mutation in the other. In three nonconsanguineous families, probands were compound heterozygous for a single-nucleotide insertion or deletion, a nonsense mutation, or a splice-site mutation. Abnormal splice products were characterized at the RNA level. Since only protein-truncating mutations were identified, regardless of clinical severity, we conclude that genotype does not predict phenotype. Having established that RBS and SC are caused by mutations in the same gene, we delineated the clinical phenotype of the tetraphocomelia spectrum that is associated with HR and ESCO2 mutations and differentiated it from other types of phocomelia that are negative for HR. (+info)
Multidisciplinary surgical approach to a surviving infant with sirenomelia.
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Sirenomelia is an extremely complex and rare malformation with different degrees of lower-extremities fusion associated with gastrointestinal, musculoskeletal, vascular, cardiopulmonary, and central nervous system malformations. In the English literature, there are only 5 reports of infants surviving with this condition. In our case, a 2540-g female infant was born with normal vital signs, no facial dysmorphism, and a complete soft tissue fusion of the lower limbs, from perineum to ankles. Radiologic examinations revealed an intestinal atresia and a single pelvic kidney, with a unique ureter, 2 femurs, 2 tibias, 2 fibulas, and 2 feet (simpus dipus). At 7 months of age, a multidisciplinary surgical team achieved complete separation of the lower limbs, with independent vascular and nerve supplies. At the time of this writing, the infant was 28 months old and had a regular growth curve. Many future reconstructive surgeries have been planned to achieve an acceptable quality of life for this infant. (+info)
Roles of the sister chromatid cohesion apparatus in gene expression, development, and human syndromes.
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The sister chromatid cohesion apparatus mediates physical pairing of duplicated chromosomes. This pairing is essential for appropriate distribution of chromosomes into the daughter cells upon cell division. Recent evidence shows that the cohesion apparatus, which is a significant structural component of chromosomes during interphase, also affects gene expression and development. The Cornelia de Lange (CdLS) and Roberts/SC phocomelia (RBS/SC) genetic syndromes in humans are caused by mutations affecting components of the cohesion apparatus. Studies in Drosophila suggest that effects on gene expression are most likely responsible for developmental alterations in CdLS. Effects on chromatid cohesion are apparent in RBS/SC syndrome, but data from yeast and Drosophila point to the likelihood that changes in expression of genes located in heterochromatin could contribute to the developmental deficits. (+info)
Mutations in WNT7A cause a range of limb malformations, including Fuhrmann syndrome and Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome.
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Fuhrmann syndrome and the Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome are considered to be distinct limb-malformation disorders characterized by various degrees of limb aplasia/hypoplasia and joint dysplasia in humans. In families with these syndromes, we found homozygous missense mutations in the dorsoventral-patterning gene WNT7A and confirmed their functional significance in retroviral-mediated transfection of chicken mesenchyme cell cultures and developing limbs. The results suggest that a partial loss of WNT7A function causes Fuhrmann syndrome (and a phenotype similar to mouse Wnt7a knockout), whereas the more-severe limb truncation phenotypes observed in Al-Awadi/Raas-Rothschild/Schinzel phocomelia syndrome result from null mutations (and cause a phenotype similar to mouse Shh knockout). These findings illustrate the specific and conserved importance of WNT7A in multiple aspects of vertebrate limb development. (+info)
Progressive nodular histiocytoma associated with thrombocytopenia with absent radii (TAR syndrome) and angiofibromas.
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A 50-year-old woman was admitted due to a long-standing history of cutaneous lesions, which were gradually increasing in number and size, located on the trunk and extremities. Histological studies confirmed the initial clinical diagnosis of histiocytomas. Moreover, the patient had numerous smooth erythematous papules on her chin and around her nose, which were diagnosed histologically as angiofibromas. The patient had congenital phocomelia. Analytical and imaging studies revealed the presence of bilateral phocomelia due to absent radii and thrombocytopenia (TAR syndrome). Multiple histiocytomas in a normolipaemic patient bring up several differential diagnoses. Slow progressive evolution without spontaneous resolution and a scattered distribution on the trunk and extremities suggest the diagnosis of progressive nodular histiocytoma. To our knowledge progressive nodular histiocytoma has not been reported previously associated either with TAR syndrome or with angiofibromas. These entities are uncommon, thus their association may not be due to chance. (+info)
Chromosome instability in a calf with amelia of thoracic limbs.
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We report here on a case of a Holstein-Friesian male calf with the congenital total absence of thoracic limbs (amelia). Cytogenetic study showed a high rate of chromosome instability, represented by chromosome or chromatid breaks and gaps in 46% of the analyzed metaphase spreads. Moreover, 12% of the spreads appeared to be polypolid. The number of micronuclei also was significantly higher when compared to control animals. This paper discusses the association between chromosome instability and limb malformation. (+info)
A case with proximal femoral focal deficiency (PFFD) and fibular A/hypoplasia (FA/H) associated with urogenital anomalies.
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Malformations of the lower limbs are rare and heterogeneous anomalies. Some congenital anomalies involving face, gastrointestinal system, skeletal system, urogenital system, heart, lung and diaphragma associated with lower limb malformations have been described in the literature. Here, we report a case of left proximal femoral focal deficiency (PFFD) together with fibular aplasia associated with left undescended testis and hypospadias. The putative embryologic mechanisms of lower limb defects and their possible association with lower urogenital tract malformations are also discussed. (+info)