Genetic studies of an acardiac monster: evidence of polar body twinning in man.

Two maternally derived chromosome sets and both maternal histocompatibility antigen haplotypes were identified in the tissues of a malformed triploid acardiac twin that developed within the same chorion as its normal twin. These findings indicate that the twins arose as a result of independent fertilizations, by two different spermatozoa, of a normal haploid ovum and its diploid first-meiotic-division polar body.

Stimulation of human hematopoietic colony formation by recombinant gibbon multi-colony-stimulating factor or interleukin 3.

Recently, the gene for a novel mammalian hematopoietic growth factor homologous to murine interleukin 3 was isolated from a gibbon T cell line and expressed in monkey COS cells. The factor, termed multi-colony stimulating factor (multi-CSF) or interleukin 3, is stimulatory to human target cells. We investigated the range of enriched human bone marrow and fetal liver hematopoietic progenitors responsive to multi-CSF; compared the colony types observed with those obtained in the presence of recombinant granulocyte-macrophage CSF (GM-CSF); and analyzed the effects on colony formation of combining multi-CSF with GM-CSF or granulocyte-CSF (G-CSF). The results show that multi-CSF acts as a multipoietin. Alone it stimulates the formation of colonies derived from granulocyte, macrophage, eosinophil, and megakaryocyte progenitors. In combination with erythropoietin it supports the development of both erythroid and mixed colonies. Furthermore, the data show that multi-CSF is a more potent stimulus of erythroid progenitors than GM-CSF. In combination with G-CSF multi-CSF substantially increases granulocyte colony number over the number obtained with each factor alone. We conclude that multi-CSF may prove to have important therapeutic potential in vivo as a stimulus for hematopoiesis.

Pathologic findings in fetal GM1 gangliosidosis.

A 24-week fetus with GM1 gangliosidosis (type 1) was studied using biochemical and histopathologic methods. Foam cells in viscera and placenta demonstrated widespread accumulation of a lipidlike material. By microscopy, central nervous system storage appeared confined to the retina and dorsal root ganglia, but the brain ganglioside content was measurably elevated compared with that of age-matched controls. These data, along with those of others, imply that, if the observed pathologic findings are irreversible, any attempts at intrauterine therapy must commence prior to the middle of the second trimester.

Diagnosis and management of infantile marfan syndrome.

Marfan syndrome is infrequently diagnosed early in infancy. The experience of the authors with 22 severely affected infants diagnosed as having Marfan syndrome in the first 3 months of life is described and the literature on 32 additional infants with Marfan syndrome is reviewed. It was found that serious cardiac pathology (82% of the patients described in the article, 94% of those described in the literature) may be present at birth, and that congenital contractures (64% of our cases, 47% of literature cases) are often an associated finding. Other useful clinical findings included arachnodactyly, dolichocephaly, a characteristic facies, a high-arched palate, micrognathia, hyperextensible joints, pes planus, anterior chest deformity, iridodenesis, megalocornea, and dislocated lenses. Echocardiography was useful as a noninvasive method for defining the extent of cardiovascular involvement and following its course. Characteristic cardiac findings in early life included mitral valve prolapse, valvular regurgitation, and aortic root dilation. Cardiac function ranged from normal to poor, with a tendency to worsen. Of the 22 cases 3 infants died during the first year of life. Morbidity and mortality may be high when Marfan syndrome is diagnosed during infancy, and prompt recognition of this phenotype can facilitate management and counseling. Most such severe cases appear to be due to a sporadic mutation in a single germ cell of one parent. Many familial cases may have milder manifestations, be more difficult to detect during infancy, and have a better prognosis.

Etiologic complexities of diaphragmatic defects: right diaphragmatic hernia, pulmonary hypoplasia/agenesis, and hydrocephalus in sibs.

Here we review the complexities of diaphragmatic defects and describe sibs with small, right diaphragmatic defects with pulmonary hypoplasia/agenesis and hydrocephalus. Despite a poor initial prognosis, the propositus has progressed remarkably well. Antenatal sonographic study detected hydrocephalus but not the diaphragmatic defect in the sib of the propositus. Because diaphragmatic defects are most commonly found in association with other anomalies and may occur in association with chromosome anomalies careful workup of all affected infants is crucial for accurate genetic counseling.

Transient cysts of the fetal choroid plexus: morphology and histogenesis.

In this report, we correlate the clinical and morphologic features of bilateral choroid plexus cysts in three fetuses. These cysts were detected as incidental findings during sonography at 18 to 20 weeks gestation before elective abortion. Two fetuses were normal; the third had trisomy 18. All cysts were present bilaterally in the posterior horns of the lateral ventricles and ranged from 0.5 cm to 1.0 cm in diameter. The walls were translucent, and the cavities were filled with clear serous fluid, except for the left cyst in the third fetus, which was hemorrhagic. The cysts were surrounded by the loose stroma of the choroid plexus. We believe that the formation of these cysts is related to the histogenesis of the choroid plexus. Although such cysts have now been described by sonographers in several fetuses with chromosomal anomalies, this association may reflect ascertainment bias. At this time, we therefore advise caution in interpreting sonographic evidence of isolated choroid plexus cysts as anomalous.

Epidemiology of osteochondrodysplasias: changing trends due to advances in prenatal diagnosis.

The osteochondrodysplasias (skeletal dysplasias) are a heterogeneous group of disorders characterized by abnormalities in cartilage and bone growth and development. Some of these disorders are detectable during the second trimester by sonographic techniques. We ascertained cases of osteochondrodysplasias in elective pregnancy terminations, stillborn infants older than 20 gestational weeks, and liveborn infants diagnosed by the fifth day of life as part of an ongoing active malformation surveillance program. Forty-nine cases of osteochondrodysplasias were identified among approximately 126,000 deliveries at Brigham and Women's Hospital (BWH) during a 15-year period (Feb. 16, 1972-Feb. 15, 1975; Jan. 1, 1979-Dec. 31, 1990). When cases delivered to women who had planned to deliver at another hospital but were transferred for high-risk care (transfers) were excluded, the prevalence rate was 2.14 cases per 10,000 deliveries. During the early period (1972-1975) no cases were suspected prenatally, while during the 1988-1990 period, 80% of all cases and 57% of cases delivered to women who had always planned to deliver at BWH (non-transfers) were suspected by ultrasonography. Birth status changed through our period of surveillance. In the final 3-year period (1988-1990), 40% of all cases and 29% of non-transfers with osteochondrodysplasias were pregnancy terminations, compared to none during the 1972-1975 period. The increasing frequency of pregnancy terminations complicated the diagnosis of these conditions. Despite extensive evaluation, a definitive diagnosis was not possible in 8 of 49 cases (16%). Biochemical and molecular genetic methods of diagnosis will continue to become more important if the current trend of wide utilization of prenatal sonography and termination of affected pregnancies continues.

Fetoplacental histology as a predictor of karyotype: a controlled study of spontaneous first trimester abortions.

It has been suggested that inferences about fetal karyotype can be made from examination of placental and decidual histology in early, spontaneous abortions (SABs). We assessed the reproducibility and predictive value of histologic features in 75 karyotyped, first trimester SABs; 32% (24 of 75) had normal male karyotypes (46,XY) and 68% (51 of 75) were cytogenetically abnormal (29 trisomy, 12 triploidy, eight monosomy X, and two tetraploidy). Three pathologists independently assessed 17 fetal, placental, and decidual histological findings and made predictions about the karyotype (normal, abnormal, or uncertain). Good to excellent interobserver and intraobserver reproducibility (kappa > 0.58) was achieved for the identification of five histological features: villous cavitation, anucleate fetal erythrocytes, amnion, umbilical cord, and fetal tissue. When histology and karyotype were compared using Fisher's exact test, no histological feature was associated with "any abnormal karyotype," two features (anucleate, fetal erythrocytes and umbilical cord) were associated with a normal karyotype, two features (villous dysmorphism and cisterns) were associated with triploidy, and four features (villous hydrops, no umbilical cord, no fetal tissue, and no anucleate erythrocytes) were associated with trisomy. Despite these significant histological-cytogenetic associations, the positive predictive values of each of these histological features with their corresponding karyotypes were low, ranging from 0.41 to 0.73 (mean, 0.53). Our data suggest that certain histological features in first trimester SABs are associated with the SAB's karyotype and are reproducible; however, such histological features did not perform as well as diagnostic tests for predicting the likelihood of normal versus abnormal karyotype.

The biology of tetraploid hydatidiform moles: histopathology, cytogenetics, and flow cytometry.

We identified three cases of tetraploid hydatidiform moles (HM). A complete hydatidiform mole (CM) had a 92,XXXX karyotype. The two partial hydatidiform moles (PM) had karyotypes of 69,XXY/90,XXXY,-11,-13 and 92,XXYY, respectively. Study of chromosomal heteromorphisms in the 92,XXYY PM revealed two maternal and two paternal haploid sets. Flow cytometric analysis of nuclear DNA content from fresh placental tissue from the 69,XXY/90,XXXY,-11,-13 PM demonstrated distinct peaks in the triploid and tetraploid regions and an octaploid G2/M peak. Flow cytometric analysis of paraffin-embedded, fixed tissue was diagnostic of tetraploidy in the 92,XXXX CM and consistent with tetraploidy in the 92,XXYY PM. All three patients achieved spontaneous remission of elevated gonadotropin levels. These three cases of tetraploid HM do not fit into the usual patterns of diploid CM and triploid PM. We conclude that flow cytometric analysis of nuclear DNA may be used to identify polyploidy in fresh and paraffin-embedded, fixed placental tissues. Categorization of all molar placentas on the basis of ploidy presents rare opportunities to study the biology and natural history of gestational trophoblastic disease in tetraploid HM.

Twins, placentas, and genetics: acardiac twinning in a dichorionic, diamniotic, monozygotic twin gestation.

We describe a human acardiac twin with associated vascular anastomoses in a dichorionic diamniotic fused twin placenta. A 22-year-old woman delivered a healthy 3,554 g male infant and a fused diamniotic dichorionic twin placenta with a 230 g umbilical cord-attached, skin-covered, ovoid mass, consistent with acardiac amorphus. By gross and histological examination, the placental dividing membranes comprised four leaves, one amnion from each placenta, and two centrally fused chorions, diagnostic of dichorionicity. Placental barium injection of the normal twin's umbilical vein showed an anastomosis with the acardiac twin which traversed the dividing membranes, then supplied major vessels of the acardiac mass via its 5.5 cm umbilical cord. DNA-typing studies of the normal twin's placenta and of the acardiac twin's tissues revealed identical alleles at 11 distinct genetic polymorphic loci, consistent with monozygosity. Our findings demonstrate that vascular anastomoses can occur in dichorionic twin placentas, and that human acardiac twinning is not, as heretofore believed, restricted to monochorionic placentas.

Massive chronic intervillositis associated with recurrent abortions.

Massive chronic intervillositis (MCI) is an unusual placental lesion associated with poor fetal growth and adverse pregnancy outcome; it has not previously been associated with spontaneous abortion or recurrent pregnancy loss. This article reports a patient who had 10 spontaneous abortions with repetitious massive chronic intervillositis documented in four of five gestations spanning all three trimesters. Characteristic placental histology induced massive infiltration of the maternal intervillous space by chronic inflammatory cells and fibrin, without associated chronic villitis; the cellular infiltrate was composed predominantly of LCA and CD68 immunoreactive cells with scattered CD45RO positivity, consistent with a monocyte/macrophage population with occasional T lymphocytes. Elevated maternal serum alpha-fetoprotein was documented in two pregnancies. These findings support the concept that this unusual placental lesion may have an immunologic basis, and suggest that MCI may be a histopathologically recognizable cause of recurrent spontaneous abortion.

Heterotopic cervical salivary gland tissue in a family with probable branchio-otorenal syndrome.

Heterotopic cervical salivary gland tissue was found in a 4-yr-old girl with branchial and otologic abnormalities. Her mother and sister also had heterotopic cervical salivary tissue in association with anomalies that suggest the branchio-otorenal (BOR) syndrome. Heterotopic cervical salivary gland tissue may result from abnormal branchial development.

Ocular findings in a new heritable syndrome of brain, eye, and urogenital abnormalities.

We studied the clinical and histopathologic ocular findings in four related males with a newly recognized syndrome consisting of microphthalmos, microencephaly, mental retardation, agenesis of the corpus callosum, hypospadius, and cryptorchidism with X-linked recessive inheritance. The ocular abnormalities include microphthalmos, corneal pannus and hypoplasia, cataracts, uveal hypoplasia, retinal dysplasia, optic nerve hypoplasia, and congenital blepharoptosis. In case 4, a female twin who died in utero (at 15 weeks' gestation) showed none of the ocular abnormalities.

GNAZ in human fetal cochlea: expression, localization, and potential role in inner ear function.

Dissociation of an activated alpha-subunit from the beta-gamma complex directly regulates secondary messenger proteins. To address the potential role of G proteins expressed in human fetal cochlea, degenerate oligonucleotide primers corresponding to the 3'-end of the conserved region of alpha-subunits were used for polymerase chain reaction amplification of reverse-transcribed total human fetal cochlear mRNAs; GNAZ and GNAQ were isolated. These two G proteins are unique among the G-protein family because they lack a typical pertussis modification site. GNAZ is expressed in high levels in neural tissue while GNAQ is ubiquitously expressed. We characterized GNAZ expression using Northern blots, tissue in-situ hybridization and immunohistochemistry techniques to elucidate the potential role of this protein in inner ear function. Our data suggest that GNAZ may play a role in maintaining the ionic balance of perilymphatic and endolymphatic cochlear fluids.

Duchenne and Becker muscular dystrophies: genetics, prenatal diagnosis, and future prospects.

DMD and BMD are now understood at the genetic, biochemical, and molecular levels. At the genetic level, both disorders result from mutations of the X-linked gene encoding dystrophin. At the biochemical level, DMD results from the deficiency of a large protein called dystrophin, whereas BMD results when dystrophin is present, though abnormal in either amount or molecular structure. To date, thousands of patients have been analyzed for mutations of the dystrophin gene in peripheral blood DNA or alterations of the dystrophin protein in muscle tissue. The severity of the clinical phenotype of these patients has been compared with their dystrophin gene mutations and corresponding dystrophin protein alterations, revealing an unexpectedly high degree of correlation. Thus, information derived from the molecular analysis (DNA or protein) of a particular patient provides a "molecular diagnosis," which is highly predictive of the clinical course that patient can be expected to follow. Because molecular diagnoses are independent of the patient's age, they provide a prognosis for the large majority of muscular dystrophy patients even before clinical symptoms of their disease become apparent. Such prognostic molecular diagnoses have proven particularly valuable when the patient is an isolated case, with no family history for the disorder. Prenatal genetic diagnosis of DMD or BMD may involve use of Southern blot or PCR techniques to search for a deletion in the DNA of at-risk fetuses or more complicated family linkage studies using intragenic and flanking RFLPs. More recently, assay of dystrophin content in fetal skeletal or cardiac muscle from at-risk abortuses has been accomplished, allowing definitive discrimination of affected and normal fetuses in cases in which deletion analyses and family DNA studies were equivocal. In utero fetal skeletal muscle biopsy for dystrophin protein assay has actually been accomplished in at least one at-risk pregnancy in which family DNA studies were uninformative. Dystrophin was present in skeletal muscle from this 20-week-old male fetus, and the pregnancy continued, resulting in the term birth of a healthy male infant. The future holds exciting opportunities for neonatal screening and treatment of these devastating neuromuscular diseases.

Questionable role of amniocentesis in the etiology of amniotic band formation. A case report.

A preterm infant had an amniotic band sequence. Anomalies included left leg amputation and digital anomalies of the hands. The umbilical cord was short, and histologic sections of the placenta demonstrated partial avulsion of the amnion and fibrosis of the underlying chorion. Ultrasound at 21 weeks was normal, there was no history of trauma during the pregnancy, and no amniocentesis had been performed. Despite isolated case reports of amniotic band sequence associated with amniocentesis, we doubt that amniotic band formation is a significant risk after second-trimester amniocentesis.

Overview of human identity testing and forensic genetics.

This unit discusses the development of the field of forensic genetics, touching on the quality control and legal issues that are central to this area. It closes with a discussion of some caveats for interpreting forensic DNA results.

Collecting and handling samples for parentage and forensics DNA-based genetic testing.

The unit covers Variable Numbers of Tandem Repeats (VNTR) based paternity analysis as well as the newer methods relying on PCR to analyze sequence specific polymorphisms and microsatellite regions. The discussion of data analysis and probability calculations has been expanded to address a number of special circumstances, such as the lack of sample from an alleged father, motherless cases, and more.

RFLP analysis of forensic DNA samples with single-locus VNTR genetic markers.

This unit covers the many and varied methods for extracting DNA from such diverse specimens as blood, tissue, stamps and envelopes, and cigarette butts, among others. Modifications to the methods that allow the DNA to be used for either PCR or Southern blotbased analyses are also included.