Linda M. Ernst

Mutations in FAM20C Are Associated with Lethal Osteosclerotic Bone Dysplasia (Raine Syndrome), Highlighting a Crucial Molecule in Bone Development

The generation and homeostasis of bone tissue throughout development and maturity is controlled by the carefully balanced processes of bone formation and resorption. Disruption of this balance can give rise to a broad range of skeletal pathologies. Lethal osteosclerotic bone dysplasia (or, Raine syndrome) is an autosomal recessive disorder characterized by generalized osteosclerosis with periosteal bone formation and a distinctive facial phenotype. Affected individuals survive only days or weeks. We have identified and defined a chromosome 7 uniparental isodisomy and a 7p telomeric microdeletion in an affected subject. The extent of the deleted region at the 7p telomere was established by genotyping microsatellite markers across the telomeric region. The region is delimited by marker D7S2563 and contains five transcriptional units. Sequence analysis of FAM20C, located within the deleted region, in six additional affected subjects revealed four homozygous mutations and two compound heterozygotes. The identified mutations include four nonsynonymous base changes, all affecting evolutionarily conserved residues, and four splice-site changes that are predicted to have a detrimental effect on splicing. FAM20C is a member of the FAM20 family of secreted proteins, and its mouse orthologue (DMP4) has demonstrated calcium-binding properties; we also show by in situ hybridization its expression profile in mineralizing tissues during development. This study defines the causative role of FAM20C in this lethal osteosclerotic disorder and its crucial role in normal bone development.

Five cases of caudal regression with an aberrant abdominal umbilical artery: Further support for a caudal regression-sirenomelia spectrum.

Sirenomelia and caudal regression have sparked centuries of interest and recent debate regarding their classification and pathogenetic relationship. Specific anomalies are common to both conditions, but aside from fusion of the lower extremities, an aberrant abdominal umbilical artery (“persistent vitelline artery”) has been invoked as the chief anatomic finding that distinguishes sirenomelia from caudal regression. This observation is important from a pathogenetic viewpoint, in that diversion of blood away from the caudal portion of the embryo through the abdominal umbilical artery (“vascular steal”) has been proposed as the primary mechanism leading to sirenomelia. In contrast, caudal regression is hypothesized to arise from primary deficiency of caudal mesoderm. We present five cases of caudal regression that exhibit an aberrant abdominal umbilical artery similar to that typically associated with sirenomelia. Review of the literature identified four similar cases. Collectively, the series lends support for a caudal regression–sirenomelia spectrum with a common pathogenetic basis and suggests that abnormal umbilical arterial anatomy may be the consequence, rather than the cause, of deficient caudal mesoderm.

ALK Expression in Rhabdomyosarcomas: Correlation with Histologic Subtype and Fusion Status

Immunohistochemical staining for anaplastic lymphoma kinase (ALK) has been described in rhabdomyosarcomas (RMS), especially the alveolar subtype. Previous studies have yielded conflicting results regarding the pattern of staining (nuclear versus cytoplasmic), and there has been no correlation with PAX3–7/FKHR fusion status. This study was undertaken to evaluate ALK receptor protein expression in a large series of RMS; to correlate these results with fusion status; and to investigate the possibility of 2p23 amplification or translocation using fluorescence in situ hybridization (FISH). Sixty-nine cases of RMS were examined and classified as alveolar RMS (ARMS), embryonal RMS (ERMS), or unclassifiable RMS (URMS) subtypes. Anaplastic lymphoma kinase immunohistochemistry was performed using anti-human CD246 antibody; cases were considered positive when more than 50% of cells had moderate or intense cytoplasmic and/or nuclear staining. There were 30 ARMS, 37 ERMS, and 2 URMS subtypes. Reverse transcription–polymerase chain reaction for PAX3/PAX7-FKHR fusion analysis had been done in all cases of ARMS, in 27 of 37 cases of ERMS, and in both URMS cases. Anaplastic lymphoma kinase staining was positive in 16 of 30 ARMS (53%) and 9 of 39 nonalveolar RMS (23%) cases (P < 0.05). Of the 21 ARMS cases with PAX3-FKHR fusion, 10 of 21 (48%) were positive for ALK staining; of the 6 ARMS cases with PAX7-FKHR fusion, 3 of 6 (50%) were positive for ALK staining; and 3 of 3 (100%) of the fusion-negative ARMS were positive with ALK staining. When comparing each of the ARMS subtypes, statistical significance was not reached. All positive cases showed dot-like cytoplasmic staining; nuclear staining was not seen. Of a subset of 6 ALK-positive ARMS submitted for break-apart FISH for the ALK locus, there was no evidence of a translocation; 1 case had ALK amplification and 2 had low-level gains of the ALK gene. We conclude that there is ALK overexpression in RMS, more commonly in ARMS than in ERMS, most likely independent of fusion status. Amplification or upregulation of ALK may underlie ALK protein overexpression.

Hamartomatous tongue lesions in children

The incidence and spectrum of tongue lesions in children, in particular tongue hamartomas, is relatively unknown. We report a retrospective review of all tongue lesions seen at a major tertiary care childrens hospital over an 18-year period with an emphasis on describing tongue hamartomas. A total of 135 tongue lesions were identified. Vascular/lymphatic lesions (36/135) were the most common followed by mucus extravasation phenomenon (22/135). Interestingly, hamartomatous lesions (18/135) were the third most common lesion category identified. Lingual hamartomas were predominantly submucosal in location and were classified histologically by tissue composition as follows: neurovascular (2/18), smooth muscle predominant (5/18), fat predominant (1/18), and smooth muscle and fat containing (10/18). All 5 smooth muscle predominant hamartomas also contained vasculature, and 1 case additionally contained salivary gland tissue. The single fat predominant hamartoma additionally contained vessels and salivary gland. The final 10 hamartomas contained varying amounts of both smooth muscle and fat, and also admixed combinations of vessels, nerves, and salivary glands. Two of these 10 cases additionally contained foci of choristomatous elements, including cutaneous adnexal structures and cartilage. Most patients with hamartomatous lesions were young, 2 years or less. Eight cases were congenital in origin. Females outnumbered males by 2:1. The majority of lesions (16/18) were dorsal in location, and 4 patients had a syndromic association, all oral-facial-digital syndrome.

Causes of Death and Autopsy Findings in a Large Study Cohort of Individuals with Cornelia de Lange Syndrome and Review of the Literature

To identify causes of death (COD) in propositi with Cornelia de Lange syndrome (CdLS) at various ages, and to develop guidelines to improve management and avoid morbidity and mortality, we retrospectively reviewed a total of 426 propositi with confirmed clinical diagnoses of CdLS in our database who died in a 41‐year period between 1966 and 2007. Of these, 295 had an identifiable COD reported to us. Clinical, laboratory, and complete autopsy data were completed on 41, of which 38 were obtainable, an additional 19 had autopsies that only documented the COD, and 45 propositi had surgical, imaging, or terminal event clinical documentation of their COD. Proband ages ranged from fetuses (21–40 weeks gestation) to 61 years. A literature review was undertaken to identify all reported causes of death in CdLS individuals. In our cohort of 295 propositi with a known COD, respiratory causes including aspiration/reflux and pneumonias were the most common primary causes (31%), followed by gastrointestinal disease, including obstruction/volvulus (19%). Congenital anomalies accounted for 15% of deaths and included congenital diaphragmatic hernia and congenital heart defects. Acquired cardiac disease accounted for 3% of deaths. Neurological causes and accidents each accounted for 8%, sepsis for 4%, cancer for 2%, renal disease for 1.7%, and other causes, 9% of deaths. We also present 21 representative clinical cases for illustration. This comprehensive review has identified important etiologies contributing to the morbidity and mortality in this population that will provide for an improved understanding of clinical complications, and management for children and adults with CdLS.

A Potential Screening Tool for IPEX Syndrome

IPEX syndrome is a rare, inherited condition characterized by immune dysfunction, polyendocrinopathy, enteropathy, and X-linked recessive inheritance. Patients typically present in infancy with severe diarrhea and failure to thrive. Most children die by 1 year of age without therapy. The diagnosis is established by genetic analysis, which often takes several weeks to complete and can sometimes delay crucial immunosuppressive treatment. We attempted to develop a screening tool that allows rapid identification of patients with IPEX syndrome using immunocytochemical staining of FOXP3+ cells in bowel biopsies. We found that 2 patients with classic IPEX syndrome due to protein-truncating mutations in FOXP3 had markedly decreased staining of FOXP3+ T cells in the lamina propria and lymphoid aggregates. One patient with a mild, late-onset presentation and a missense mutation in FOXP3 had intact staining of FOXP3+ cells. This screening test provides a valuable tool for diagnosing IPEX syndrome in extremely ill patients who may not tolerate a delay in therapeutic intervention.

Can placental pathology explain second-trimester pregnancy loss and subsequent pregnancy outcomes?

OBJECTIVE This study sought to determine whether specific placental pathology may provide further insight into the mechanisms of second-trimester pregnancy loss, particularly in cases without inflammation. STUDY DESIGN A blinded pathologist examined placentas from 90 patients with spontaneous second-trimester pregnancy loss and 17 controls who presented for induction of labor for fetal indications. Inflammation was staged and evidence of other vascular pathology recorded. Significant associations were determined by chi(2) analysis and Fishers exact test. A secondary analysis examined losses without inflammation. Twelve patients with a subsequent pregnancy were also evaluated. RESULTS Acute inflammation was more prevalent in cases than controls (P < .001). Sixty-seven percent of all cases and none of the controls showed a stage 2-3 inflammatory response. Histologic abruption was also more prevalent in cases than controls (P = .05). CONCLUSION Second-trimester pregnancy loss is strongly associated with placental inflammation. Histologic abruption is likely another etiology. Future research should focus on subsequent pregnancy outcomes in these women based on initial placental pathology to help determine etiology and recurrence risk.

Interlobular Bile Duct Loss in Pediatric Cholestatic Disease is Associated with Aberrant Cytokeratin 7 Expression by Hepatocytes

The objective of this study was to determine whether aberrant hepatic expression of cytokeratin 7 (CK7) and/or other putative stem cell markers is seen in pediatric cholestatic diseases. Eighteen liver biopsies and 14 liver explants from pediatric patients with extrahepatic biliary atresia (EHBA), Alagille syndrome (AGS), primary sclerosing cholangitis (PSC), inborn errors of bile acid synthesis, and progressive familial intrahepatic cholestasis (PFIC) were examined along with 5 histologically normal control liver biopsies. Immumohistochemical stains (CK7, CD56, and OV6) were performed on paraffin-embedded tissue. Staining of interlobular bile ducts (ILBD), proliferating bile ductules, and hepatocytes was scored using a semiquantitative scale. There were significant differences in CK7 staining of hepatocytes among the cholestatic diseases (P < 0.006). All cases with AGS showed CK7 hepatocyte staining, while EHBA and PSC had variable hepatocyte staining. Patients with PFIC had prominent CK7 hepatocyte staining, while those with inborn errors of bile acid synthesis had little. Control biopsies showed rare hepatocyte staining. Analysis based on the presence or absence of ILBD revealed significantly more CK7 hepatocyte staining in cases with loss of ILBD (P < 0.001). CD56 staining of hepatocytes was also present more frequently in cases with absent or reduced ILBD. Regardless of underlying disease, loss of ILBD is a major determinant of aberrant expression of CK7 by hepatocytes. Aberrant CK7 expression may reflect a metaplastic change to a “stem cell” phenotype induced by loss of contact with the more distal biliary tree.

Intraplacental smooth muscle tumor : A case report

We present the second reported case of a smooth muscle neoplasm involving the placental parenchyma. On gross examination, the tumor easily separated from the uterus and had a whorled cut surface with finger-like extensions into the villous parenchyma, very similar to the previously described case. The differential diagnosis included a primary smooth muscle tumor of the placenta (placental leiomyoma), a primary uterine neoplasm incorporated into the placenta, and a metastatic sarcoma. In this case, the infant was male, and the polymerase chain reaction technique demonstrated the presence of Y chromosome gene in the placental parenchyma and its absence in the placental neoplasm. Thus, this neoplasm, despite its gross appearance of a primary placental tumor, actually represented an incorporated benign uterine leiomyoma.

A second leiomyosarcoma in the urinary bladder of a child with a history of retinoblastoma 12 years following partial cystectomy

This case describes a twin with bilateral retinoblastoma who developed leiomyosarcoma of the bladder at age 17 and again at 39. At 17‐years of age she was diagnosed with a leiomyosarcoma of the bladder after presenting with recurrent urinary tract infections, hematuria, and dysuria. She was treated with partial cystectomy. After a 12‐year disease‐free interval, she was diagnosed with a second leiomyosarcoma of the bladder. This case supports the relationship between the genetic form of retinoblastoma and leiomyosarcoma and illustrates the necessity for extensive follow‐up and well‐defined treatment of secondary neoplasms.