Double mutant fibrillin-1 (FBN1) allele in a patient with neonatal Marfan syndrome

It is now well established that defects in fibrillin-1 (FBN1) cause the variable and pleiotropic features of Marfan syndrome (MFS) and, at the most severe end of its clinical spectrum, neonatal Marfan syndrome (nMFS). Patients with nMFS have mitral and tricuspid valve involvement and aortic root dilatation, and die of congestive heart failure, often in the first year of life. Although mutations in classical MFS have been observed along the entire length of the FBN1 mRNA, mutations in nMFS appear to cluster in a relatively small region of FBN1, approximately between exons 24 and 34. Here we describe the appearance of two FBN1 mutations in a single allele of an infant with nMFS. The changes were within six bases of each other in exon 26. One was a T3212G transversion resulting in an I1071S amino acid substitution and the second was an A3219T transversion resulting in an E1073D amino acid substitution. This is the first reported double mutant allele in FBN1.     

Prenatal detection of chromosome aneuploidies in uncultured chorionic villus samples by FISH

We developed a 1-d FISH assay for detection of numerical chromosome abnormalities in uncultured chorionic villus samples (CVS). Probes specific for chromosomes 13, 18, 21, X, and Y were used to determine ploidy by analysis of signal number in hybridized nuclei. Aneuploidy detection using this assay was directly compared with the results obtained by conventional cytogenetic analysis in a consecutive, clinical study of 2,709 CVS and placental samples. The FISH assay yielded discrete differences in the signal profiles between cytogenetically normal and abnormal samples. On the basis of these results, we generated FISH-assay cutoff values that discriminated between karyotypically normal and aneuploid samples. Samples with mosaicism and a single sample with possible heritable small chromosome X probe target were exceptions and showed poor agreement between FISH results and conventional cytogenetics. We conclude that the FISH assay may act as a more accurate and less labor-demanding alternative to "direct" CVS analysis.     

Preimplantation genetic diagnosis in Marfan syndrome

Melanoma has a better prognosis in women than in men, may be exacerbated by pregnancy, and has been to reported to respond to hormonal manipulations. Laboratory investigations have demonstrated that both animal and human melanomas may respond to changes in the hormonal milieu. Steroid hormone binding activity has been demonstrated in some human melanomas, but only a small percentage of melanomas respond to hormonal manipulation. Randomized trials suggest a possible role for tamoxifen in combination with chemotherapy for metastatic melanoma and for megestrol acetate as an adjuvant. Nevertheless, it appears that the use of steroid hormones in the management of melanoma is limited.     

Marfan syndrome: diagnosis of cardiovascular manifestations]

BACKGROUND: Despite the availability of several different markers for Epstein--Barr virus (EBV) serology, the EBV status of some patients cannot be resolved from a single serum sample with routine testing. To avoid the requirement of follow-up samples, supplementary tests have to be used in these cases. OBJECTIVE: To evaluate the usefulness of avidity and immunoblot assays as supplementary tests for the diagnosis of acute EBV infections. STUDY DESIGN: Three groups of samples for which a definite diagnosis on the EBV status could not be obtained with the routine serological tests were further examined by an EBV IgG avidity assay, by an immunoblot based on a lysate of EBV infected cells, and by a second immunoblot based on recombinant EBV antigens. The three groups consisted of 38 samples with negative/borderline EB nuclear antigen 1 (EBNA-1) antibodies, negative/borderline EBV IgM and positive EBV IgG; 10 samples with indeterminate EBNA-1 and/or EBV IgM assays because of control antigen reactions; and 4 samples with positive EBV IgM results that were not plausible. RESULTS: The avidity assay differentiated between acute and past infections for all samples. In contrast, some cases remained unresolved with both the recombinant and the lysate immunoblot. Two samples were incorrectly classified with the lysate immunoblot. Interpretation of the lysate immunoblot banding patterns was complicated when anticellular antibodies were present. CONCLUSION: Avidity testing appears to be the confirmatory method of choice to differentiate between acute and past EBV infections.     

Prenatal diagnosis of Apert syndrome

Apert syndrome (AS) is clinically characterized by typical facial features and symmetrical syndactyly of the digits. AS is inherited as an autosomal dominant trait. Recently, a fibroblast growth factor receptors 2 (FGFR2) mutation, either C934G or C937G, was identified in exon IIIa. Our report documents an affected mother and son in whom one of the two mutations in AS had occurred sporadically in the mother. The diagnosed of AS was based on associated abnormal physical features and on molecular genetic analysis. A C-to-G transversion at position 937 of the cDNA resulting in a proline-to-arginine substitution at codon 259 was found in the mother. In her second pregnancy, prenatal diagnosis by both restriction analysis and direct sequencing was undertaken and this showed that the female fetus had not inherited the mutation.     

Prenatal diagnosis of the fragile X syndrome: loss of mutation owing to a double recombinant or gene conversion event at the FMR1 locus

The fragile X syndrome, an X linked mental retardation syndrome, is caused by an expanded CGG repeat in the first exon of the FMR1 gene. In patients with an expanded repeat the FMR1 promoter is methylated and, consequently, the gene is silenced and no FMR1 protein (FMRP) is produced, thus leading to the clinical phenotype. Here we describe a prenatal diagnosis performed in a female from a fragile X family carrying a large premutation. In chorionic villus DNA of the male fetus the normal maternal CGG allele and a normal pattern on Southern blot analysis were found in combination with the FRAXAC2 and DXS297 allele of the maternal at risk haplotype. A second chorionic villus sampling was performed giving identical results on DNA analysis and, in addition, expression of FMRP was shown by immunohistochemistry. We concluded that the male fetus was not affected with the fragile X syndrome. Subsequent detailed haplotype analysis showed a complex recombination pattern resembling either gene conversion or a double crossover within a 20 kb genomic region.     

Prenatal diagnosis of beta-thalassemia. Detection of a single nucleotide mutation in DNA

We investigated a method employing synthetic oligonucleotides for the prenatal diagnosis of beta-thalassemia due to a single nucleotide mutation. The beta 0 thalassemia we tested is produced by a nonsense mutation and is commonly found in Sardinia and other parts of the Mediterranean. In this DNA lesion, the glutamine codon CAG at the beta 39 position is mutated to TAG, which results in a stop codon and premature termination of the beta-globin chain. We synthesized two oligonucleotides: one homologous to the normal beta A gene and the other to the beta 0 thalassemia gene at the beta 39 location. The oligonucleotides were labeled with 32P and used as hybridization probes for normal and thalassemic DNA. The beta A probe hybridized only to the normal DNA, and the beta-thalassemia probe only to thalassemic DNA, thus providing a technique for direct demonstration of the mutation. The method is sensitive enough to be applied directly to DNA that is isolated from uncultured cells obtained from only 20 ml of amniotic fluid as early as the 16th gestational week.     

Prenatal diagnosis of pseudothalidomide syndrome in consecutive pregnancies of a consanguineous couple

Sacrococcygeal teratomas can be diagnosed prenatally with a detailed ultrasound examination of the fetal anatomy. The majority of these teratomas are solid or mixed cystic and solid external caudal masses. A conclusion drawn from the literature is that only a small percentage are entirely cystic and few are completely internal or presacral without external component (Type IV). This report describes an unusual case of a large completely internal cystic sacrococcygeal teratoma identified prenatally by ultrasonography at 32 weeks' gestation. The differential diagnosis for this unique presentation of sacrococcygeal teratoma is different from that considered for predominantly external complex tumors.     

Prenatal diagnosis of a pancreatic cyst due to Ivemark II syndrome

We present a case of pancreatic cyst associated with other malformations which was diagnosed at antenatal ultrasound. Renal, hepatic, and pancreatic dysplasia as described by Ivemark in 1959 was confirmed by the pathology examination. This uncommon and lethal syndrome demonstrates autosomic recessive transmission. Ultrasound evidence of renal, hepatic and pancreatic dysplasia, associated with femoral abnormalities is suggestive of Meckel's syndrome. Other differential diagnoses are more easily distinguished (chondrodysplasia, chromosomal or metabolic abnormalities).     

Prenatal ultrasonographic and molecular diagnosis of Apert syndrome

Apert syndrome is a rare craniosynostosis syndrome with significant bilateral syndactyly of the hands and feet. Usually it is detected by ultrasonography during the third trimester unless there is a family history. We present an interesting sporadic case with features consistent with Apert syndrome detected as early as the first trimester. A first-trimester ultrasound evaluation prior to chorionic villus sampling (CVS) for maternal age 41 was within normal limits except for the suggestion of a 'mitten-like' hand and proximally placed thumb. Mid-trimester ultrasound was not diagnostic; however, following the development of polyhydramnios in the third trimester, the evaluation of the digits and facial features were strongly suggestive of Apert syndrome. Amniocentesis was performed and a molecular diagnosis of Apert syndrome was made and confirmed on cord blood.     

Prenatal sonographic diagnosis of Treacher Collins syndrome: a case and review of the literature

We report the prenatal ultrasonographic diagnosis of a fetus with mandibulofacial dysostosis (Treacher Collins syndrome). Sonographic findings included: polyhydramnios, microcephaly, abnormal fetal facial features (slanting forehead, microphthalmos, micrognathia), and abnormal fetal swallowing. A review of the current literature pertaining to prenatal diagnosis of this condition is presented.     

Culture of first-trimester and full-term human chorionic villus explants: role of human chorionic gonadotropin and human placental lactogen as a viability index

In long-term cultures of human chorionic villus explants, the viability of the tissue must be controlled to ensure the reliability of functional studies. Ionic levels (pH), gas concentrations (pO2, pCO2) and metabolic markers (glucose, lactate) in the culture medium are often utilized. Analyses of hormone, enzyme and protein levels are also frequently used to estimate viability. The purpose of this study was to evaluate whether in vitro release and immunoreactivity of human chorionic gonadotropin (hCG) and human placental lactogen (hPL) were correlated with the viability of first-trimester and full-term chorionic villus explants as determined by histopathology. Villus explants of first-trimester and full-term pregnancies were incubated in 6-well plates of RPMI medium which was supplemented with 10% fetal calf serum. Incubations were performed for 10 days, and the plates were kept at 37 degrees C under a water-saturated atmosphere containing 5% CO2 and 95% O2. The medium was replaced every day and samples of supernatant were frozen for later testing of hCG (first trimester) or hPL (full term), glucose consumption and lactate production. The tissue was also fixed and embedded for light-microscopic examination and immunocytochemistry. The hCG release remained stable during 6-7 days at a high level before decreasing, whereas hPL release decreased during the first 5-6 days then stabilized at a relatively low level. Only hCG kinetics were significantly different between tissue incubated with and without cycloheximide or iodoacetic acid. Both hCG and hPL immunoreactivity were not significantly different between tissue cultures with, and without, addition of cycloheximide or iodoacetic acid and even with morphological evidence of trophoblast and endothelial necrosis. The immunoreactivity for both hormones remains highly positive when the significant release has stopped, and does not reflect the tissue viability.     

Prenatal diagnosis of cardiac osteoma: a case report

Primary benign intracardiac tumours in the infant period are rare. We report a case of a cardiac osteoma detected at 17 weeks of gestation. Ultrasonographically, it appeared as a calcified mass with a sharp margin and was associated with hypoplastic right ventricle. The gross and histological findings are presented.     

Defective calcium binding to fibrillin-1: consequence of an N2144S change for fibrillin-1 structure and function

Fibrillin-1 is a major structural component of 10-12 nm connective tissue microfibrils and has a modular organisation that includes 43 calcium binding epidermal growth factor-like (cbEGF) domains and seven transforming growth factor beta-binding protein-like (TB) domains. Mutations in the fibrillin-1 (FBN1) gene cause the Marfan syndrome (MFS) and related connective tissue disorders. We have previously investigated an N2144S change, identified in a MFS patient, which removes one of the key calcium binding ligands within cbEGF domain 32. In this study the structural consequences of the N2144S amino acid change for the folding and calcium binding properties of mutant and wild-type TB6-cbEGF32 and cbEGF32-33 domain pairs have been analysed by nuclear magnetic resonance. The presence of an N2144S substitution does not alter the native fold of either the TB6 domain, or cbEGF domains 32 and 33. Comparison of calcium dissociation constants measured for the wild-type and mutant pairs shows that: (i) the affinity of cbEGF32 is weakly enhanced by N-terminal linkage of TB6 relative to cbEGF32 in isolation; (ii) the affinity of cbEGF32 is approximately ninefold decreased by the N2144S substitution in the TB-cbEGF pair; and (iii) reduced affinity of cbEGF32 does not result in lower affinity of cbEGF33 for calcium. Together, these data suggest that the TB6-cbEGF32 linkage is flexible and the structural effect of the mutation is localised to the interdomain linkage. We have also investigated the effect of defective calcium binding to cbEGF32 on fibrillin-1 produced by N2144S MFS fibroblasts. 35S-pulse-chase analysis shows that the N2144S substitution does not detectably affect fibrillin-1 biosynthesis, rate of secretion or processing. Deposition of reducible fibrillin-1 into the extracellular matrix was also unaffected. The implications of these results for the assembly and properties of the microfibril are discussed.     

Prenatal molecular diagnosis of RET proto-oncogene mutation in multiple endocrine neoplasia type 2A

We report a case of multiple endocrine neoplasia type 2A (MEN 2A) diagnosed prenatally at 16 weeks gestation. The 35-year-old mother is a MEN 2A patient. She had had three prior pregnancies: one resulted in a stillbirth; one produced a genetically unaffected boy; and the third was terminated in the first trimester owing to a diagnosis of blighted ovum. Autopsy did not reveal the cause of death of the stillborn infant, who was also found to be affected with MEN 2A by molecular study of paraffin-embedded tissue. Because of poor obstetric history and the patient's age, amniocentesis for cytogenetic and molecular studies was performed at 16 weeks' gestation during the pregnancy under discussion. As with other affected members in the mother's family, the missense mutation of TGC to TTC at codon 634 of the RET proto-oncogene was found in amniotic fluid cells. Analysis of DNA extracted from the lymphocytes of the infant's blood at birth confirmed the diagnosis. To our knowledge, this is the first report of prenatal diagnosis of MEN 2A.     

Management of a short femur discovered via ultrasound in utero. Prenatal diagnosis of Stuve-Wiedemann syndrome

BACKGROUND: Malignant mesothelioma reportedly shows different epidemiology and pathology in females, and a proportion are believed to arise spontaneously. METHODS: One hundred and seventy seven cases of malignant mesothelioma in females were reviewed, examined by histochemistry and immunohistochemistry, assessed for asbestosis and lung fibre burden by transmission electron microscopy with energy dispersive x ray analysis, and compared with 31 female controls. RESULTS: Two of one hundred and three cases tested for carcinoembryonic antigen were positive and were excluded from further analysis. Tumour cases showed increased amphibole burdens; in those in whom exposure information was known, 74 (80%) of 93 patients had a history of exposure to asbestos. Seventy two (47%) of 152 patients had lung fibrosis. Tumour site and histological type were little different from those reported in adult males. Mixed type histological pattern, lung fibrosis, and peritoneal site were associated with heavier lung asbestos burdens, but not exclusively. Thirty five (30%) of 117 patients had amphibole burdens of less than 2 x 10(6) fibres/g; the sites affected and the histological pattern of tumours in this group were similar to those in cases with amphibole fibre counts of > or = 2 x 10(6)/g lung. A higher lung amphibole burden than the mean burden in control females was found in 115 (98%) of 117 patients tested. CONCLUSIONS: The pathology of malignant mesothelioma appears to be similar in women and in men, and in cases associated and unassociated with asbestos.     

Marfan syndrome with coronary artery lesions in a North American Indian

From a preliminary evaluation, many of the disadvantages of the conventional arch bars appear to be overcome with this new technique. Of particular importance is that no anesthetic is required during placement of the arch bars except when needed for aligning displaced segments or open reductions. The laboratory work can be delegated to a technician, and operating time rarely exceeds an hour. Further evaluation is being done.     

Prenatal diagnosis of a fetal mediastinal teratoma

BACKGROUND: Adequate excision of invasive penile carcinoma often results in a penile stump of inadequate length to control the urinary stream. A simple technique to lengthen the stump and avoid urethrostomy is described here. METHODS: Additional corporal length is gained by dividing the dorsal suspensory ligaments through a transverse lower abdominal skin incision. Skin length is gained by vertical closure of this incision. RESULTS: This technique has been successful in two cases where the stump length after partial penectomy was borderline. Each patient has a functional stump with satisfactory cosmesis. CONCLUSIONS: In selected cases this technique may avert the need for perineal urethrostomy after adequate excision of a penile cancer.