Jessica M. Comstock

A Family-Based Paradigm to Identify Candidate Chromosomal Regions for Isolated Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a developmental defect of the diaphragm that causes high newborn mortality. Isolated or non‐syndromic CDH is considered a multifactorial disease, with strong evidence implicating genetic factors. As low heritability has been reported in isolated CDH, family‐based genetic methods have yet to identify the genetic factors associated with the defect. Using the Utah Population Database, we identified distantly related patients from several extended families with a high incidence of isolated CDH. Using high‐density genotyping, seven patients were analyzed by homozygosity exclusion rare allele mapping (HERAM) and phased haplotype sharing (HapShare), two methods we developed to map shared chromosome regions. Our patient cohort shared three regions not previously associated with CDH, that is, 2q11.2–q12.1, 4p13 and 7q11.2, and two regions previously involved in CDH, that is, 8p23.1 and 15q26.2. The latter regions contain GATA4 and NR2F2, two genes implicated in diaphragm formation in mice. Interestingly, three patients shared the 8p23.1 locus and one of them also harbored the 15q26.2 segment. No coding variants were identified in GATA4 or NR2F2, but a rare shared variant was found in intron 1 of GATA4. This work shows the role of heritability in isolated CDH. Our family‐based strategy uncovers new chromosomal regions possibly associated with disease, and suggests that non‐coding variants of GATA4 and NR2F2 may contribute to the development of isolated CDH. This approach could speed up the discovery of the genes and regulatory elements causing multifactorial diseases, such as isolated CDH.

Composite pheochromocytoma: a clinicopathologic and molecular comparison with ordinary pheochromocytoma and neuroblastoma.

Composite pheochromocytoma is a rare adrenal tumor composed of ordinary pheochromocytoma and other components, most frequently neuroblastic elements. Little is known about its biologic potential, therefore creating a clinical dilemma on diagnosis. This study investigates the clinical characteristics and N-myc amplification status of 4 cases of composite pheochromocytoma and compares them with selected cases of ordinary pheochromocytoma and neuroblastoma. The age range of the patients with composite pheochromocytoma was 15 to 40 years with an equal M/F ratio, including 2 patients with syndromes. None of these composite pheochromocytomas demonstrated N-myc amplification, none recurred, and there were no deaths. Of the classic pheochromocytomas, none demonstrated N-myc amplification, 2 recurred, and there were no deaths. Of the neuroblastomas, 5 (50%) of 10 showed significant N-myc amplification, and there were 4 known recurrences and 5 known deaths. These findings suggest that composite pheochromocytoma may be regarded as a histologic variant of classic pheochromocytoma.

MORTALITY AND PATHOLOGICAL FINDINGS IN C (OPITZ TRIGONOCEPHALY) SYNDROME

Even as a rare multiple congenital anomalies/mental retardation syndrome, the C-syndrome (CS, or Opitz C-trigonoecephaly syndrome) is, at long last, beginning to attract attention because of its developmental and causal complexity. Also, the possibility that the apparently balanced translocation recently described in an affected Japanese boy may soon provide a molecular/causal insight into this disorder. The manifestations recorded in the previously published patients, those autopsied within recent years, and the unpublished instances in our files suggest that the CS is a heterogeneous genetic disorder, predominantly sporadic but with sufficient familial cases (at times with consanguinity) to allow postulation of an entity due to autosomal dominant mutations with a high rate of germinal mosaicism, or due to both autosomal dominant mutations and an autosomal recessive genocopy. In any event, elucidation of cause and pathogenesis of CS will, in due time, shed light on its developmental pleiotropy, rarity in liveborn infants, prevalence in stillborn fetuses, recurrence risk in humans, and occurrence in other animals (e.g., mice) to further understanding of pathogenesis.

Activated NOTCH2 is Overexpressed in Hepatoblastomas: An Immunohistochemical Study

Hepatoblastoma is a pediatric malignancy characterized by the uncontrolled proliferation of immature hepatocytes (hepatoblasts). This disease is diagnosed primarily in children younger than 5 years and is disproportionately observed in former premature infants. Cytogenetically, hepatoblastoma is characterized by numerical aberrations, as well as unbalanced translocations involving the proximal region of chromosome 1q. The NOTCH2 gene has been mapped to this locus, and it is well established that the NOTCH gene family is an important regulator of several developmental pathways. Specifically, the NOTCH2 protein is known to delay hepatoblast maturation during early hepatic organogenesis, and the reduction of NOTCH2 expression correlates with the differentiation of hepatoblasts into hepatocytes and biliary cells in the developing liver. We hypothesized that NOTCH2 is involved in the pathogenesis of hepatoblastoma by maintaining a population of undifferentiated hepatoblasts. We studied the immunohistochemical expression of NOTCH2 and its isoforms NOTCH1, NOTCH3, and NOTCH4 and the NOTCH2 primary ligand JAGGED1 in hepatoblastomas. Compared with the normal liver, an increasedlevelofNOTCH2expressionwasseenin22of 24 (92%) hepatoblastomas. There was no significant staining for other NOTCH isoforms and JAGGED1 in hepatoblastomas. Therefore, we suggest that NOTCH2 expression and activation, independent of JAGGED1 expression, may contribute to the pathogenesis of hepatoblastoma. In the hepatoblastoma sinusoidal vasculature, we saw NOTCH3 and NOTCH1 expression. These observations have potential implications with regard to therapeutic targeting of the NOTCH signaling pathway in hepatoblastomas.

Recurrence of Achondrogenesis Type 2 in Sibs: Additional Evidence for Germline Mosaicism

Achondrogenesis Type II (ACG2) is a lethal skeletal disorder caused by a dominant mutation in the type II collagen gene (COL2A1). Familial cases have been reported, suggesting both germline and somatic mosaicism. We report on two pregnancies from the same couple with gross, radiologic, and microscopic findings of ACG2. Molecular analysis of the second infant demonstrated heterozygosity for a c.2303G > A transition (p.Gly768Asp) in exon 33 of the COL2A1 gene. Although this mutation could not be proven by molecular studies in the first infant, identical findings in two affected pregnancies support germline mosaicism as the cause of ACG2 in this family.

Prenatal death in Fraser syndrome.

Cryptophthalmos may be partial or complete, unilateral or bilateral, apparently nonsyndromal or syndromal. A recent study of 2 stillborn infants at the University of Utah prompted an analysis of the developmental aspects of the syndromal form (Fraser syndrome). We conclude that, per se, cryptophthalmos is a developmental field defect on the basis of heterogeneity (autosomal dominant and recessive forms) and phylogeneity (occurrence also in the pheasant, rabbit, pigeon, dog, and mouse). In humans this autosomal recessive disorder maps to 4q21, is homologous to the bleb (bl/bl) mouse, and is due to mutations in the FRAS1 gene that codes for a 4007 amino acid protein 85% identical to the Fras1 gene of the bleb mouse. Commonest anomalies in humans are cryptophthalmos, cutaneous syndactyly of digits, abnormal ears and genitalia, renal agenesis, and congenital heart defects. Almost half of affected infants are stillborn or die in infancy, and mental retardation is common. The pathogenesis evidently involves abnormal epithelial integrity during prenatal life. Older (mostly German) publications, some dating to the 19th century, provide a fascinating historical insight into the process of syndrome delineation.

Denys-Drash syndrome with neonatal renal failure in monozygotic twins due to c.1097G>A mutation in the WT1 gene.

Denys-Drash syndrome, characterized by nephrosis, dysgenetic gonads and a predisposition to Wilms tumor, is due to germline mutations in the WT1 gene. We report the pathologic findings on monozygotic twins, both of whom presented with male pseudohermaphroditism, nephrotic syndrome, and progressed to renal failure and death within the first month of life. Sequence analysis of WT1 demonstrated a G-to-A substitution in exon 8 of the gene (c.1097G > A), resulting in an arginine-to-histidine (R366H) substitution in the second zinc finger domain. To the best of our knowledge, this is only the second set of monozygotic twins with Denys-Drash syndrome reported to date.

Pediatric pathology fellowship graduates of ACGME-accredited programs: survey findings.

There are several ways of measuring outcomes of subspecialty training in pathology. A couple of the more easily identified or measured methods include whether a graduate continues to practice the subspecialty she trained in or if she has passed the American Board of Pathology (ABP) examination in her subspecialty. Training programs routinely collect this information on their graduates. Here we report the findings of a survey that the Fellowship Committee of the Society for Pediatric Pathology (SPP) undertook to understand the paths taken by the fellows graduating from pediatric pathology fellowship programs. In September 2013, the Fellowship Committee of the SPP sent a survey to pediatric pathology fellowship directors to gather information about prior fellows. We received responses back from 22 out of 24 programs. The results of the survey showed that for the 5-year academic period from 2007 through 2012, approximately 77 fellows enrolled in pediatric pathology fellowships, of which 5 withdrew. Of the 72 graduates, at least 57 (79%) have taken the ABP certification exam for pediatric pathology. The data indicate that 21% of otherwise-eligible graduates chose not to appear for the ABP examination! Furthermore, of the 57 test-takers, 54 received the ABP certification in pediatric pathology. The survey indicated a board certification rate of approximately 95%, which likely includes repeaters of the examination and does not necessarily suggest a board pass rate of 1st-time test-takers. Approximately 50% of fellows completed another fellowship in addition to pediatric pathology. Most pediatric pathology graduates (86%) are practicing pediatric pathology at least part time. The graduates most often work at children’s hospitals (71%), but a significant percentage are working as both adult and pediatric pathologists (at least 48%). The graduates have not taken any professional positions with the National Institutes of Health, the Centers for Disease Control and Prevention, the Veterans Administration, or other federal governmental agencies. Data obtained from the public records of the American Council of Graduate Medical Education (ACGME) revealed the enrolled trainee number to be 121 during the study period (2007 to 2012). Thus, our survey did not capture information on approximately one third of the enrolled fellows from the studied period [1]. Our survey showed a trend among trainees to undertake 2 fellowships following pathology residency. The ABP’s pediatric pathology board pass rate for the 1st-time testtakers has shown significant fluctuations over the last 5 years. The pass rate of 1st-time test-takers varied from 76% in 2009 [2] to 69% in 2012 [3] and, most recently, to 100% in 2014 [4]. Our survey revealed that 21% of graduating fellows are not appearing for the pediatric pathology board examination. The graduating fellows who sat for the board examination did a commendable job of eventually obtaining the certification. However, the finding that 21% of graduates were not interested in obtaining board certification could be a source of concern. Being boardcertified positively affects a graduate’s employment prospects, and for the fellowship program, it provides an objective measure of its quality to the ACGME. In summary, the survey indicates that the outcomes of pediatric pathology fellowship programs suggest a successful endeavor, with the vast majority (86%) of the graduating fellows practicing pediatric pathology and 95% of the test-takers obtaining board certifications with the ABP.

Fetal Thrombotic Vasculopathy

Abstract Fetal thrombotic vasculopathy (FTV) is the term used to encompass the histologic findings identified in placentas with fetal thrombotic lesions: occlusive and nonocclusive chorionic vessel thrombi, avascular villi in the distribution of a single villous tree, intramural vascular fibrin, and hemorrhagic endovasculitis. The underlying etiology of FTV is largely unknown though hypercoagulability and circulatory stasis have been the main focuses in the literature to explain the hemostatic abnormalities. This article reviews the literature in both defining and discussing, potential etiologies of FTV, as well as neonatal outcomes.

Gestational Psittacosis Resulting in Neonatal Death Identified by Next-Generation RNA Sequencing of Postmortem, Formalin-Fixed Lung Tissue

Abstract Psittacosis is a rare zoonosis that can cause severe disease and adverse outcomes during pregnancy. We identified a previously elusive case of psittacosis causing premature delivery and infant death by next-generation RNA sequencing of postmortem tissues. Hypothesis-free pathogen detection in postmortem specimens can increase the yield of epidemiologic and cause-of-death studies.