Isolation of DNA from forensic evidence

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.

Interpretation of complex forensic DNA mixtures

Forensic evidentiary samples routinely contain DNA from multiple contributors. The interpretation of these mixtures can be a challenging task for the DNA scientist. Several approaches are discussed (no calculation- qualitative statement; probability of exclusion; likelihood ratio estimates; presumptive genotype assignment based on peak heights), which have been employed to assess the significance of an inclusion/match when DNA mixtures have been detected in casework samples. These statistical approaches are discussed in light of technical challenges that can arise when evaluating evidentiary samples.

Manual methods for PCR-based forensic DNA analysis

This unit provides validated PCR-based methods to test for sequence polymorphisms and length polymorphisms. It includes a description of the reverse dot blot method for detecting sequence polymorphisms. The forensic PCR systems used to detect length polymorphisms are based on detection of different-sized PCR products following electrophoresis in either native or denaturing polyacrylamide gels. The unit offers a description of the amplification and detection of the variable number of tandem repeat (VNTR) length polymorphism at the D1S80 locus. It also describes the multiplex amplification of three separate autosomal short tandem repeats (STRs) and the X- and Y-linked amelogenin alleles. These PCR products are electrophoresed on a denaturing polyacrylamide gel. Support protocols for creating permanent records of silver-stained gels, checking the quality of reagents, and interpreting PCR-based tests are provided.

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.

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.

Fluorescence in situ hybridization (FISH) for rapid detection of aneuploidy: experience in 911 prenatal cases

Fluorescence in situ hybridization (FISH) was performed with probes specific for chromosomes 13, 18, 21, X and Y on 911 of 11123 (8.2%) amniotic fluid samples submitted to the present authors' laboratory for cytogenetic analysis over an 8-year period. Altogether 3516 hybridizations were performed with an interpretable FISH result on all chromosomes requested in 884/911 (97%) of cases. An uninformative FISH result occurred in 44 hybridizations among 27 cases (3%). Of a total of 89 karyotypically proven cases with aneuploidy that might have been detected by FISH, the overall detection rate was 84%. An inconclusive or incomplete FISH result occurred in 9/89 (10%) of these proven aneuploid cases. In the remaining 80 informative proven aneuploid cases, correct detection of aneuploidy was accomplished in 75/80 (94%) of samples. A false-negative result occurred in the remaining 5/80 (6%) of such informative cases. Eighteen cases had karyotypically proven abnormalities that could not have been detected by the targeted FISH. Aside from these 18 cases, FISH allowed correct detection of normal disomy in 785/804 (98%) of such cases. An incomplete FISH result occurred in 18 normal disomic cases. There was a single possible 'false-positive' FISH result for chromosome 21. Interphase FISH analysis of uncultured amniotic fluid cells has been shown to be a useful laboratory tool for rapid fetal aneuploidy screening during pregnancy. As with all clinical laboratory diagnostic tests, incomplete or inconclusive results (or even interpretive errors) occur in a small percentage of cases. Nevertheless, FISH results accompanied by other data and by appropriate counseling provide clinicians and patients with valuable information for clinical decision-making surrounding family planning and pregnancy management.

Detection of mosaicism in amniotic fluid cultures: a CYTO2000 collaborative study

PURPOSE

To evaluate the assumptions on which the American College of Medical Genetics (ACMG) Standards and Guidelines for detecting mosaicism in amniotic fluid cultures are based.

METHODS

Data from 653 cases of amniotic fluid mosaicism were collected from 26 laboratories. A chi-square goodness-of-fit test was used to compare the observed number of mosaic cases with the expected number based on binomial distribution theory.

RESULTS

Comparison of observed data from the in situ colony cases with the expected distribution of cases detected based on the binomial distribution did not reveal a significant difference (P = 0.525).

CONCLUSIONS

The empirical data fit the binomial distribution. Therefore, binomial theory can be used as an initial discussion point for determining whether ACMG Standards and Guidelines are adequate for detecting mosaicism.

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.

Mapping and characterization of a novel cochlear gene in human and in mouse: a positional candidate gene for a deafness disorder, DFNA9

Previously we identified a partial human cDNA for a novel cochlear transcript, hCoch-5B2 (HGMW-approved symbol D14S564E), using subtractive hybridization techniques. Herein we report isolation and characterization of both human and mouse (D12H14S564E) cDNAs for Coch-5B2. Full-length Coch5B2 deduced amino acid sequences reveal a very high degree of conservation in the coding region (89% nucleotide and 94% amino acid identity and a potential signal peptide and two regions of extensive homology to the collagen-binding type A domains of von Willebrand factor, also present in other secreted proteins, including extracellular matrix components. High levels of hCoch-5B2 expression are seen only in human fetal inner ear structures, cochlea, and vestibule, among a large panel of human fetal and adult tissues. Coch-5B2 expression in the mouse is more widespread than in the human, with message detected in mouse adult spleen, cerebrum, cerebellum/medulla, and thymus. In both species very low level expression is detected in total eye. More specifically, mouse retina shows a higher level of mCoch-5B2 message than sclera and choroid. We have mapped hCoch-5B2 to human 14q11.2-q13 by somatic cell hybrid analysis and FISH and, more precisely, using radiation hybrids to a region of markers linked to DFNA9, a nonsyndromic autosomal dominant sensorineural hearing loss with vestibular defects. Furthermore, we detect hCoch-5B2 on three overlapping YACs, two of which also contain one of the markers linked to DFNA9. mCoch-5B2 was genetically mapped in the mouse to chromosome 12, in a region of homologous synteny with human 14q11.2-q13, which contains the asp1 (audiogenic seizure prone) locus in the mouse.

An ancient conserved gene expressed in the human inner ear: identification, expression analysis, and chromosomal mapping of human and mouse antiquitin (ATQ1)

We constructed and screened a human fetal cochlear cDNA library to identify genes involved in hearing and deafness. From this library we isolated a cDNA corresponding to the highly conserved ancient gene antiquitin (ATQ1). The plant homolog of ATQ1 is thought to be involved in regulating turgor pressure, a function that also would be essential for cells of the mammalian cochlea. Northern blots of 13 human fetal tissues show antiquitin to be highly expressed in cochlea, ovary, eye, heart, and kidney. Using RT-PCR of rat cochlear hair cell-specific cDNA libraries, we detect antiquitin expression in outer hair cells, but not in inner or vestibular type 1 hair cells, suggesting that antiquitin is not expressed ubiquitously in the cochlea. Human ATQ1 was mapped to human chromosome region 5q31 using fluorescence in situ hybridization, and mouse ATQ1 was mapped to mouse chromosome 18 by single-strand conformation polymorphism mapping of interspecific backcross progeny DNAs. Four human antiquitin-like sequences, possibly pseudogenes, were also identified and mapped.

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.

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.

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.

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.

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.

Expression of the Kallmann syndrome gene in human fetal brain and in the manipulated chick embryo

Kallmann syndrome is an inherited disorder characterized by an abnormality in olfactory system development. The gene for the X-linked form of this disorder (KAL) maps to Xp22.3 and encodes a protein sharing homologies with molecules involved in neuronal migration and axonal pathfinding. Here we report the expression pattern of the KAL gene in various parts of the human fetal brain. We found KAL transcripts in granule cells of the olfactory bulb and the cerebellum, in the dorsomedial thalamus and in the developing cerebral cortex. To determine whether or not signals from the olfactory nerve are required for KAL expression in the olfactory bulb, we analyzed chick embryos in which the olfactory placode was surgically removed. Those embryos lacking an olfactory nerve had a histologically abnormal bulb which nevertheless expressed the KAL gene at high levels. These findings indicate that, while the development of the proper cytoarchitecture of the olfactory bulb requires the innervation by olfactory axons, the expression of KAL is independent of such developmental processes.

Isolation of novel and known genes from a human fetal cochlear cDNA library using subtractive hybridization and differential screening

We used a combination of subtractive hybridization and differential screening strategies to identify genes that may function normally in hearing and, when mutated, result in deafness. A human fetal cochlear (membranous labyrinth) cDNA library was subtracted against total human fetal brain RNAs by an avidin-biotin-based procedure to enrich for cochlear transcripts. Subtracted cochlear clones were differentially screened with 32P-labeled total cochlear and total brain cDNA probes. Sequence analysis of clones that hybridized more intensely with cochlear than with brain cDNA probes revealed some previously characterized genes, including mitochondrial sequences, collagen type I alpha-2 (COL1A2), collagen type II alpha-1 (COL2A1), collagen type III alpha-1 (COL3A1), spermidine/spermine N1-acetyltransferase (SAT), osteonectin (SPARC), and peripheral myelin protein 22 (PMP22). Also identified were clones that are potential novel cochlear genes. Northern blots of cochlear and brain RNAs probed with COL1A2, COL2A1, COL3A1, SAT, SPARC, PMP22, and a novel sequence, designated Coch-5B2, confirm results of the subtractive procedure by showing preferential cochlear expression. A number of these genes serve structural or regulatory functions in extracellular matrix or neural conduction; defects in some of these genes are associated with disorders involving hearing loss. Partial sequence analysis of Coch-5B2 reveals a von Willebrand factor type A-like domain in this cDNA. To assess the cochlear specificity of Coch-5B2, a Northern blot panel of 14 human fetal tissue RNAs was probed with Coch-5B2, showing differential expression of this novel gene in the cochlea.

Prenatal sonography in trisomy 9

Two cases of trisomy 9 are presented with the description of the prenatal sonographic findings prompting prenatal cytogenetics evaluation. The characteristic sonographic abnormalities included structural heart defects; limb, renal, and facial anomalies; and intrauterine growth retardation. The clinical course and cytogenetic and autopsy finding are described.

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.

Complexities of limb anomalies: the lower extremity in the "prune belly" phenotype

The so-called "prune belly" syndrome (PBS) consists of megalocystis, cryptorchidism, and marked abdominal distension; in addition to these findings, many other abnormalities are commonly present, rarely including severe anomalies of the leg. We report two such individuals, in whom PBS coexisted with abnormal development of the lower extremity. The first, a still-born male fetus, was delivered at 21 weeks gestation; generalized hypoplasia of both legs was present, more marked distally than proximally, and more severe on the left. The second case, a liveborn male infant, was the second of dichorionic twins, delivered at 33 weeks gestation; this infant died at two hours from respiratory insufficiency due to pulmonary hypoplasia. There was severe hypoplasia of the right leg, with gangrenous necrosis of all tissues distal to the knee. Additional findings included a single right umbilical artery, and a small congenital cystic adenomatoid malformation of the right lung. The findings in these cases are compared to other similar cases in the literature, and possible mechanisms for the etiology and pathogenesis of maldevelopment of the leg in PBS are discussed.

Homologous ribosomal protein genes on the human X and Y chromosomes: escape from X inactivation and possible implications for Turner syndrome

We have isolated two genes on the human sex chromosomes, one on the Y and one on the X, that appear to encode isoforms of ribosomal protein S4. These predicted RPS4Y and RPS4X proteins differ at 19 of 263 amino acids. Both genes are widely transcribed in human tissues, suggesting that the ribosomes of human males and females are structurally distinct. Transcription analysis revealed that, unlike most genes on the X chromosome, RPS4X is not dosage compensated. RPS4X maps to the long arm of the X chromosome (Xq), where no other genes are known to escape X inactivation. Curiously, RPS4X maps near the site from which the X-inactivating signal is thought to emanate. On the Y chromosome, RPS4Y maps to a 90 kb segment that has been implicated in Turner syndrome. We consider the possible role of RPS4 haploinsufficiency in the etiology of the Turner phenotype.

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.

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.

Dystrophin analysis in duchenne muscular dystrophy: use in fetal diagnosis and in genetic counseling

In this report we describe the use of dystrophin analysis both in the diagnosis of Duchenne muscular dystrophy (DMD) in an aborted fetus and in genetic counseling. Our consultand's initial carrier risk, as based on family history and creatine kinase determinations, was calculated as 0.6%. DNA analysis of her family (and fetus) modified this risk to 8.5%. Skeletal muscle of the 23-wk male abortus was found to be histologically indistinguishable from that of age-matched controls. However, immunoblot testing for dystrophin indicated that the fetus had indeed inherited dystrophin deficiency. The carrier risk of the consultand was thus elevated to 100%. Dystrophin assays should be employed whenever the diagnosis of fetal DMD is equivocal (e.g., cases in which a gene deletion cannot be identified). Assay results are crucial for genetic counseling for subsequent pregnancies and for studies of the early pathogenesis of muscular dystrophy.

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.

Incidence of spontaneous abortion among normal women and insulin-dependent diabetic women whose pregnancies were identified within 21 days of conception

Whether pregnant women with insulin-dependent diabetes mellitus have an increased risk of spontaneous abortion is controversial. To address this question, we enrolled 386 women with insulin-dependent diabetes and 432 women without diabetes before or within 21 days after conception and followed both groups prospectively. Sixty-two diabetic women (16.1 percent) and 70 control women (16.2 percent) had pregnancy losses (odds ratio, 0.99; 95 percent confidence interval, 0.67 to 1.46). After adjustment for known risk factors for spontaneous abortion, the rate was still not significantly higher in the diabetic group (odds ratio, 0.91; 95 percent confidence interval, 0.59 to 1.40). Nonetheless, among the diabetic women, most of whom had good metabolic control, those who had spontaneous abortions had higher fasting and postprandial glucose levels in the first trimester than those whose pregnancies continued to delivery (P = 0.01 for fasting glucose levels and P = 0.005 for postprandial levels). In the small subgroup of diabetic women with poor control, who had elevated values for glycosylated hemoglobin in the first trimester, each increase of 1 SD above the normal range was associated with an increase of 3.1 percent in the rate of pregnancy loss (95 percent confidence interval, 0.6 to 5.6). We conclude that diabetic women with good metabolic control are no more likely than nondiabetic women to lose a pregnancy, but that diabetic women with elevated blood glucose and glycosylated hemoglobin levels in the first trimester have a significantly increased risk of having a spontaneous abortion.

Lack of relation of increased malformation rates in infants of diabetic mothers to glycemic control during organogenesis

To determine how much insulin-dependent diabetes increases a woman's risk of giving birth to a malformed infant and how that risk is influenced by metabolic control, we followed 347 diabetic and 389 control women who enrolled in the study within 21 days of conception (the early-entry group) and 279 diabetic women who entered later (the late-entry group). We detected major malformations in the infants of 4.9 percent of the early-entry diabetic women, 2.1 percent of the controls, and 9.0 percent of the late-entry diabetic women. Malformation rates were significantly higher among offspring of early-entry diabetic women than among those of controls (odds ratio, 2.45; lower one-sided 95 percent confidence limit, 1.12; P = 0.027), and higher among late-entry than among early-entry diabetic women (odds ratio, 1.91; lower one-sided 95 percent confidence limit, 1.07; P = 0.032). Mean blood glucose and glycosylated hemoglobin levels during organogenesis were not significantly higher in women whose infants were malformed. Hypoglycemia (glucose, less than or equal to 50 mg per deciliter [2.8 mmol per liter]) was not significantly more common in the same group. Hyperglycemia and glycosylated hemoglobin were not correlated with malformation. The data suggest that more sensitive measures are needed to identify the teratogenic mechanisms, or that not all malformation can be prevented by good glycemic control. Despite the increased malformation rate among infants of the early-entry diabetic women, as compared with the controls, the more favorable outcome seen in the former group as compared with the late-entry group justifies the attempt to achieve good metabolic control around the time of conception.

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.

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.

Normal cellular counterparts of B cell chronic lymphocytic leukemia

In an attempt to compare B cell chronic lymphocytic leukemia (B-CLL) with its normal cellular counterpart, the cell surface phenotype of 100 cases of B-CLL was determined by using a panel of monoclonal antibodies (MoAbs) directed against B cell-restricted and -associated antigens. The majority of B-CLL cells expressed Ia, B4 (CD19), B1 (CD20), B2 (CD21), surface immunoglobulin (sIg), and T1 (CD5) but lacked C3b (CD35) receptors. In contrast, the overwhelming majority of small unstimulated B cells expressed Ia, B4, B1, B2, sIg, and C3b receptors but lacked detectable T1. Small numbers of weakly sIg+ cells could be identified in peripheral blood and tonsil that coexpressed the B1 and T1 antigens. Approximately 16% of fetal splenocytes coexpressed B1, T1, weak sIg, B2, and Ia but lacked C3b receptors and therefore closely resembled most B-CLL cells. With the phenotypic differences between the majority of small unstimulated B cells and B-CLL cells, we examined normal in vitro activated B cells and B-CLL cells for the expression of B cell-restricted and -associated activation antigens. Of 20 cases examined, virtually all expressed B5, and approximately 50% of the cases expressed interleukin-2 receptors (IL-2R) and Blast-1. Normal B cells were activated with either anti-Ig or 12-0-tetradecanoylphorbol-beta-acetate (TPA) and then were examined for coexpression of B1, T1, and the B cell activation antigens B5 and IL-2R. Only cells activated with TPA coexpressed B1 and T1 as well as B5 and IL-2R. B cells activated with either anti-Ig or TPA proliferated in the presence of IL-2, whereas B-CLL cells did not, although they all expressed the identical 60-kilodalton proteins by immunoprecipitation. These studies are consistent with the notion that B-CLL resembles several minor subpopulations of normal B cells including a population of B cells that are activated in vitro directly through the protein kinase C pathway.

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.

Transposition of the external genitalia associated with caudal regression

Complete transposition of the external genitalia is a rare abnormality that occasionally is associated with the caudal regression syndrome. We report the pathological findings of this abnormality in a male stillborn and a female newborn. The male stillborn had extensive urogenital anomalies as well as complete transposition of the external genitalia and agenesis of the lumbar spine. The female patient had renal tract anomalies and ambiguous external genitalia with a phallic structure in the gluteal cleft. In surviving infants with transposition of the external genitalia immediate evaluation of the urogenital system is necessary to identify the full extent of any associated internal defects.

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.

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.

The fetal face: ultrasound examination

Abnormalities of the fetal face were identified by ultrasound in five cases. Abnormalities such as cleft lip and palate, cyclopia, and forms of holoprosencephaly were diagnosed prenatally. Two of the fetuses had trisomy 13. When facial abnormalities are identified a careful search of the fetus for associated anomalies is indicated; amniocentesis for genetic study may be desirable. In addition, evaluation of the fetal face may be useful when other fetal abnormalities are present.

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.