Mutations in a novel gene lead to kidney tumors, lung wall defects, and benign tumors of the hair follicle in patients with the Birt-Hogg-Dubé syndrome.

Birt-Hogg-Dubé (BHD) syndrome is a rare inherited genodermatosis characterized by hair follicle hamartomas, kidney tumors, and spontaneous pneumothorax. Recombination mapping in BHD families delineated the susceptibility locus to 700 kb on chromosome 17p11.2. Protein-truncating mutations were identified in a novel candidate gene in a panel of BHD families, with a 44% frequency of insertion/deletion mutations within a hypermutable C(8) tract. Tissue expression of the 3.8 kb transcript was widespread, including kidney, lung, and skin. The full-length BHD sequence predicted a novel protein, folliculin, that was highly conserved across species. Discovery of disease-causing mutations in BHD, a novel kidney cancer gene associated with renal oncocytoma or chromophobe renal cancer, will contribute to understanding the role of folliculin in pathways common to skin, lung, and kidney development.

School nurses and children with diabetes: a descriptive study.

BACKGROUND: Managing diabetes in children is complex. The aims of this descriptive study were to describe the care provided to children with diabetes by school nurses using case management, to identify differences in care on the basis of the workload of the nurse and the age of the child, to explore the role of the nurse in responding to emergencies, and to describe the relationship between case management and quality of life. METHODS: School nurses completed an expanded health assessment. Individualized goals were established and interventions were provided on the basis of a protocol. Quantitative and qualitative data for children enrolled during the 2009-2010 academic year were analyzed. RESULTS: Eighty-six children were enrolled. The most common goals were related to establishing a safe school environment. Interventions varied depending on the workload of the nurse and the age of the child. Nurses assigned to 1-2 schools provided more intervention days (mean, 40.3 days) than did nurses assigned to 3-4 schools (mean, 24.4 days) (P < .05), particularly in the area of direct care. A total of 25 students experienced an emergency at school that initiated a cascade of events involving the parent (in 100% of cases), the teacher (in 96%), management of hyperglycemia (in 100%), and/or management of hypoglycemia (in 96%). For teens, case management improved quality of life, particularly the ability to communicate with health professionals. LIMITATIONS: The sample was small, and there was no comparison group. CONCLUSIONS: School nurses are effective in using case management to enhance the health and well-being of children with diabetes. This study should be replicated with a larger sample, a comparison group, and the inclusion of clinical outcomes.

Defining, delivering, and documenting the outcomes of case management by school nurses.

Case management is a component of school nurse practice that provides an opportunity to demonstrate the contribution that school nurses make to the health and academic success of children, particularly children with chronic health conditions. However, case management programs vary in their mission and scope, leading to confusion about what it means to be a case manager. Many programs acknowledge the difficulty in tracking outcomes and sustaining results. Using a capacity-building approach, the Case Management Project (CMP) developed a definition of case management and a set of baseline and outcome measures to assist school nurses to become effective case managers and track their outcomes.

School nurse case management for children with chronic illness: health, academic, and quality of life outcomes.

More children with chronic illnesses are attending school, and some of them struggle academically because of issues related to their health. School-based case management has been suggested as one strategy to improve the academic success of these children. This study tracked the academic, health, and quality of life outcomes for 114 children with asthma, diabetes, severe allergies, seizures, or sickle-cell anemia in 5 different school districts who were provided case management by school nurses. The children ranged in age from 5 to 19 years. At the end of the school year, children experienced an improvement in quality of life and gained skills and knowledge to manage their illness more effectively. Classroom participation, grades, and participation in extracurricular activities also increased for many children. The study provides evidence of the positive impact school nurses have on children with chronic illness and suggests ways they can measure the outcomes of their interventions.

Kidney-targeted Birt-Hogg-Dube gene inactivation in a mouse model: Erk1/2 and Akt-mTOR activation, cell hyperproliferation, and polycystic kidneys.

BACKGROUND: Patients with Birt-Hogg-Dubé (BHD) syndrome harbor germline mutations in the BHD tumor suppressor gene that are associated with an increased risk for kidney cancer. BHD encodes folliculin, a protein that may interact with the energy- and nutrient-sensing 5'-AMP-activated protein kinase-mammalian target of rapamycin (AMPK-mTOR) signaling pathways. METHODS: We used recombineering methods to generate mice with a conditional BHD allele and introduced the cadherin 16 (KSP)-Cre transgene to target BHD inactivation to the kidney. Kidney cell proliferation was measured by BrdU incorporation and phospho-histone H3 staining. Kidney weight data were analyzed with Wilcoxon's rank-sum, Student's t, and Welch's t tests. Hematoxylin and eosin staining and immunoblot analysis and immunohistochemistry of cell cycle and signaling proteins were performed on mouse kidney cells and tissues. BHD knockout mice and kidney cells isolated from BHD knockout and control mice were treated with the mTOR inhibitor rapamycin. Mouse survival was evaluated by Kaplan-Meier analyses. All statistical tests were two-sided. RESULTS: BHD knockout mice developed enlarged polycystic kidneys and died from renal failure by 3 weeks of age. Targeted BHD knockout led to the activation of Raf-extracellular signal-regulated protein kinase (Erk)1/2 and Akt-mTOR pathways in the kidneys and increased expression of cell cycle proteins and cell proliferation. Rapamycin-treated BHD knockout mice had smaller kidneys than buffer-treated BHD knockout mice had (n = 4-6 mice per group, relative kidney/body weight ratios, mean = 4.64% vs 12.2%, difference = 7.6%, 95% confidence interval = 5.2% to 10.0%; P < .001) and longer median survival time (n = 4-5 mice per group, 41.5 vs 23 days; P = .0065 ). CONCLUSIONS: Homozygous loss of BHD may initiate renal tumorigenesis in the mouse. The conditional BHD knockout mouse may be a useful research model for dissecting multistep kidney carcinogenesis, and rapamycin may be considered as a potential treatment for Birt-Hogg-Dubé syndrome.

Folliculin encoded by the BHD gene interacts with a binding protein, FNIP1, and AMPK, and is involved in AMPK and mTOR signaling.

Birt-Hogg-Dubé syndrome, a hamartoma disorder characterized by benign tumors of the hair follicle, lung cysts, and renal neoplasia, is caused by germ-line mutations in the BHD(FLCN) gene, which encodes a tumor-suppressor protein, folliculin (FLCN), with unknown function. The tumor-suppressor proteins encoded by genes responsible for several other hamartoma syndromes, LKB1, TSC1/2, and PTEN, have been shown to be involved in the mammalian target of rapamycin (mTOR) signaling pathway. Here, we report the identification of the FLCN-interacting protein, FNIP1, and demonstrate its interaction with 5' AMP-activated protein kinase (AMPK), a key molecule for energy sensing that negatively regulates mTOR activity. FNIP1 was phosphorylated by AMPK, and its phosphorylation was reduced by AMPK inhibitors, which resulted in reduced FNIP1 expression. AMPK inhibitors also reduced FLCN phosphorylation. Moreover, FLCN phosphorylation was diminished by rapamycin and amino acid starvation and facilitated by FNIP1 overexpression, suggesting that FLCN may be regulated by mTOR and AMPK signaling. Our data suggest that FLCN, mutated in Birt-Hogg-Dubé syndrome, and its interacting partner FNIP1 may be involved in energy and/or nutrient sensing through the AMPK and mTOR signaling pathways.

Germline BHD-mutation spectrum and phenotype analysis of a large cohort of families with Birt-Hogg-Dubé syndrome.

Birt-Hogg-Dubé syndrome (BHD), a genodermatosis characterized by multiple hamartomas of the hair follicle (fibrofolliculoma), predisposes individuals to an increased risk of developing renal neoplasms and spontaneous pneumothorax. Previously, we localized the BHD locus (also known as FLCN) to chromosome 17p11.2 by linkage analysis and subsequently identified germline mutations in a novel gene in probands from eight of the nine families with BHD in our screening panel. Affected members of five of the families inherited an insertion/deletion of a cytosine in a C8 tract in exon 11. This mutation was also identified by exon 11 screening in probands from 22 of 52 additional families with BHD and therefore represents a hypermutable "hotspot" for mutation in BHD. Here, we screened the remaining 30 families from this large BHD cohort by direct sequence analysis and identified germline BHD mutations in 84% (51/61) of all families with BHD recruited to our study. Mutations were located along the entire length of the coding region, including 16 insertion/deletion, 3 nonsense, and 3 splice-site mutations. The majority of BHD mutations were predicted to truncate the BHD protein, folliculin. Among patients with a mutation in the exon 11 hotspot, significantly fewer renal tumors were observed in patients with the C-deletion than those with the C-insertion mutation. Coding-sequence mutations were not found, however, in probands from two large families with BHD whose affected members shared their family's BHD-affected haplotype. Of the 53 families with BHD whose members inherited either a germline mutation or the affected haplotype, 24 (45%) had at least one member with renal neoplasms. Three families classified with familial renal oncocytoma were identified with BHD mutations, which represents the first disease gene associated with this rare form of renal neoplasm. This study expands the BHD-mutation spectrum and evaluates genotype-phenotype correlations among families with BHD.

A germ-line insertion in the Birt-Hogg-Dubé (BHD) gene gives rise to the Nihon rat model of inherited renal cancer.

A rat model of hereditary renal carcinoma (RC) was found in a rat colony of the Sprague-Dawley strain in Japan and named the "Nihon" rat. In heterozygotes, RCs, predominantly the clear cell type, develop from early preneoplastic lesions, which began to appear as early as 3 weeks of age, to adenocarcinomas by the age of 6 months. The Nihon rat is an example of a Mendelian dominantly inherited predisposition for development of RCs like the Eker (Tsc2 gene mutant) rat. We have previously shown that the Nihon mutation was tightly linked to genes that are located on the distal part of rat chromosome 10. The order of the genes is the Eker (Tsc2 gene (human 16p13.3)-Il3 gene-Nihon gene-Llgl1 locus- Myhse gene. We now describe a germ-line mutation in the Birt-Hogg-Dubé gene (Bhd) (human 17p11.2) caused by the insertion of a single nucleotide in the Nihon rat, resulting in a frameshift and producing a stop codon 26 aa downstream. We found that the homozygous mutant condition was lethal at an early stage of fetal life in the rat. We detected a high frequency of loss of heterozygosity (LOH) in primary RCs (10/11) at the Bhd locus and found a point mutation (nonsense) in one LOH-negative case, fitting Knudson's "two-hit" model. The Nihon rat may therefore provide insights into a tumor-suppressor gene that is related to renal carcinogenesis and an animal model of human BHD syndrome.

Expression of Birt-Hogg-Dubé gene mRNA in normal and neoplastic human tissues.

Birt-Hogg-Dubé (BHD) syndrome is an inherited autosomal genodermatosis characterized by hamartomas of the hair follicle called fibrofolliculomas and an increased risk for developing spontaneous pneumothorax, lung cysts and renal neoplasia. BHD was localized to chromosome 17p11.2 by linkage analysis in BHD families, and germline insertion/deletion and nonsense mutations in a novel gene were identified which were predicted to prematurely truncate the BHD protein, folliculin. No homology to other human proteins was found although folliculin was conserved across species. As a first step toward understanding the function of BHD in the cell and how BHD mutations can lead to the BHD phenotype, we measured the expression of BHD mRNA in normal and neoplastic human tissues by fluorescent in situ hybridization. BHD mRNA was expressed in a variety of tissues, including the skin and its appendages, the distal nephron of the kidney, stromal cells and type 1 pneumocytes of the lung, acinar cells of the pancreas and parotid gland, and epithelial ducts of the breast and prostate. In the brain, BHD mRNA was expressed in neurons of the cerebrum, and Purkinje cells in the cerebellum. BHD mRNA was also expressed in macrophage and lymphocytes in the tonsils and spleen. Tissues with reduced expression of BHD mRNA included heart, muscle and liver. BHD mRNA was expressed strongly in the proliferating epithelial strands of fibrofolliculomas, the cutaneous lesions characteristic of BHD, but not in renal tumors from BHD patients. These results indicate a wide expression pattern for BHD mRNA in many tissues, including skin, lung and kidney, which are involved in the BHD phenotype, and support a tumor suppressor role for BHD in renal cancer.

Early onset hereditary papillary renal carcinoma: germline missense mutations in the tyrosine kinase domain of the met proto-oncogene.

PURPOSE: Hereditary papillary renal carcinoma (HPRC) is characterized by a predisposition to multiple, bilateral papillary type 1 renal tumors caused by inherited activating missense mutations in the tyrosine kinase domain of the MET proto-oncogene. In the current study we evaluated the clinical phenotype and germline MET mutation of 3 new HPRC families. We describe the early onset clinical features of HPRC. MATERIALS AND METHODS: We identified new HPRC families of Italian (family 177), Spanish (family 223) and Cuban (family 268) descent. We evaluated their clinical features, performed MET mutation analysis by denaturing high performance liquid chromatography and DNA sequencing, and estimated age dependent penetrance and survival using Kaplan-Meier analysis. We characterized renal tumors by histology and fluorescence in situ hybridization. RESULTS: Identical germline MET c.3522G --> A mutations (V1110I) were identified in families 177 and 268 but no evidence of a founder effect was found. Affected members of family 223 carried a germline c.3906G --> C.3522G --> A MET mutation (V1238I). Age dependent penetrance but not survival was significantly earlier for the c.3522G -->A mutation than for the c.3906G --> A mutation in these HPRC families. Trisomy of chromosome 7 and papillary renal carcinoma type 1 histology were detected in papillary renal tumors. CONCLUSIONS: HPRC can occur in an early onset form. The median age for renal tumor development in these 3 HPRC families was 46 to 63 years. HPRC associated papillary renal tumors may be aggressive and metastasize, leading to mortality. Median survival age was 60 to 70 years. Families with identical germline mutations in MET do not always share a common ancestor. HPRC is characterized by germline mutations in MET and papillary type 1 renal tumor histology.

Mutations in the fumarate hydratase gene cause hereditary leiomyomatosis and renal cell cancer in families in North America.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal dominant disorder characterized by smooth-muscle tumors of the skin and uterus and/or renal cancer. Although the identification of germline mutations in the fumarate hydratase (FH) gene in European families supports it as the susceptibility gene for HLRCC, its role in families in North America has not been studied. We screened for germline mutations in FH in 35 families with cutaneous leiomyomas. Sequence analysis revealed mutations in FH in 31 families (89%). Twenty different mutations in FH were identified, of which 18 were novel. Of these 20 mutations, 2 were insertions, 5 were small deletions that caused frameshifts leading to premature truncation of the protein, and 13 were missense mutations. Eleven unrelated families shared a common mutation: R190H. Eighty-one individuals (47 women and 34 men) had cutaneous leiomyomas. Ninety-eight percent (46/47) of women with cutaneous leiomyomas also had uterine leiomyomas. Eighty-nine percent (41/46) of women with cutaneous and uterine leiomyomas had a total hysterectomy, 44% at age < or =30 years. We identified 13 individuals in 5 families with unilateral and solitary renal tumors. Seven individuals from four families had papillary type II renal cell carcinoma, and another individual from one of these families had collecting duct carcinoma of the kidney. The present study shows that mutations in FH are associated with HLRCC in North America. HLRCC is associated with clinically significant uterine fibroids and aggressive renal tumors. The present study also expands the histologic spectrum of renal tumors and FH mutations associated with HLRCC.