Multiple cutaneous and uterine leiomyomata resulting from missense mutations in the fumarate hydratase gene

Inherited skin tumour syndromes

This article provides an overview of selected genetic skin conditions where multiple inherited cutaneous tumours are a central feature. Skin tumours that arise from skin structures such as hair, sweat glands and sebaceous glands are called skin appendage tumours. These tumours are uncommon, but can have important implications for patient care. Certain appendageal tumours, particularly when multiple lesions are seen, may indicate an underlying genetic condition. These tumours may not display clinical features that allow a secure diagnosis to be made, necessitating biopsy and dermatopathological assessment. Coupled with robust clinical assessment, biopsy findings can guide genetic testing as, increasingly, the causative genes are known for these conditions. Here we review illustrative examples of appendageal tumours and relevant advances made in genetic discovery, and suggest when referral to a geneticist may need to be considered.

Novel splice site mutation in the fumarate hydratase (FH) gene is associated with multiple cutaneous leiomyomas in a Japanese patient

Cutaneous leiomyoma is a benign skin tumor that originates from the smooth muscle, such as the arrector pili muscle of the hair follicles. Familial cases with multiple cutaneous leiomyomas exist, which typically show an autosomal dominant inheritance trait. Most patients with the disease are known to carry heterozygous germ line mutations in the fumarate hydratase (FH) gene and can be complicated by tumors in internal organs, especially uterine leiomyoma and renal cell cancer in high frequency. In this study, we identified a Japanese male patient with multiple cutaneous leiomyomas and found a novel heterozygous splice site mutation, c.738 + 2T>A, in the FH gene of the patient, which was unexpectedly inherited from his unaffected father. Further analysis demonstrated loss of heterozygosity in the tumor tissue, which resulted in a hemizygote state of the mutant allele. Expression studies with the tumor tissue showed that the mutation led to skipping of exon 5 at mRNA levels, which was predicted to cause an in-frame deletion of FH protein (p.Ser186_Gln246del). The protein structure analysis strongly suggested that the deletion would severely disrupt the conformation of the FH protein including the substrate-binding domain, and thus would severely affect the expression and the function. Our findings further disclose the molecular basis of multiple cutaneous leiomyomas and also provide precious information to the mutation carriers in the family for an early diagnosis of renal cell cancer in the future.

Hereditary leiomyomatosis and renal cell cancer (HLRCC): renal cancer risk, surveillance and treatment

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal dominant condition in which susceptible individuals are at risk for the development of cutaneous leiomyomas, early onset multiple uterine leiomyomas and an aggressive form of type 2 papillary renal cell cancer. HLRCC is caused by germline mutations in the fumarate hydratase (FH) gene which inactivate the enzyme and alters the function of the tricarboxylic acid (Krebs) cycle. Issues surrounding surveillance and treatment for HLRCC-associated renal cell cancer were considered as part of a recent international symposium on HLRCC. The management protocol proposed in this article is based on a literature review and a consensus meeting. The lifetime renal cancer risk for FH mutation carriers is estimated to be 15 %. In view of the potential for early onset of RCC in HLRCC, periodic renal imaging and, when available, predictive testing for a FH mutation is recommended from 8 to 10 years of age. However, the small risk of renal cell cancer in the 10-20 years age range and the potential drawbacks of screening should be carefully discussed on an individual basis. Surveillance preferably consists of annual abdominal MRI. Treatment of renal tumours should be prompt and generally consist of wide-margin surgical excision and consideration of retroperitoneal lymph node dissection. The choice for systemic treatment in metastatic disease should, if possible, be part of a clinical trial. Screening procedures in HLRCC families should preferably be evaluated in large cohorts of families.

Uterine smooth muscle tumors with features suggesting fumarate hydratase aberration: detailed morphologic analysis and correlation with S-(2-succino)-cysteine immunohistochemistry

Rare, sporadic uterine leiomyomas arise in the setting of severe metabolic aberration due to a somatic fumarate hydratase mutation. Germline mutations account for the hereditary leiomyomatosis and renal cell carcinoma syndrome, which predisposes for cutaneous and uterine leiomyomas and aggressive renal cell carcinomas. Altered fumarate hydratase leads to fumarate accumulation in affected cells with formation of S-(2-succino)-cysteine, which can be detected with the polyclonal antibody. High levels of these modified cysteine residues are found characteristically in fumarate hydratase-deficient cells but not in normal tissues or tumors unassociated with hereditary leiomyomatosis and renal cell carcinoma syndrome. We hypothesized that S-(2-succino)-cysteine-positive leiomyomas, indicating fumarate hydratase aberration, have morphologic features that differ from those without S-(2-succino)-cysteine positivity. Hematoxylin and eosin-stained slides of uterine smooth-muscle tumors were prospectively analyzed for features suggesting hereditary leiomyomatosis and renal cell carcinoma syndrome, such as prominent eosinophilic macronucleoli with perinucleolar halos, yielding nine cases. Germline genetic testing for fumarate hydratase mutations was performed in three cases. A detailed morphological analysis was undertaken, and S-(2-succino)-cysteine immunohistochemical analysis was performed with controls from a tissue microarray (leiomyomas (19), leiomyosarcomas (29), and endometrial stromal tumors (15)). Of the nine study cases, four had multiple uterine smooth muscle tumors. All cases had increased cellularity, staghorn vasculature, and fibrillary cytoplasm with pink globules. All cases had inclusion-like nucleoli with perinuclear halos (7 diffuse, 1 focal). All showed diffuse granular cytoplasmic labeling with the S-(2-succino)-cysteine antibody. Two of three tested patients had germline fumarate hydratase mutations. Only one leiomyoma from the tissue microarray controls was immunohistochemically positive, and it showed features similar to other immunohistochemically positive cases. Smooth-muscle tumors with fumarate hydratase aberration demonstrate morphological reproducibility across cases and S-(2-succino)-cysteine immuno-positivity. Although the features described are not specific for the germline fumarate hydratase mutation or the hereditary leiomyomatosis and renal cell carcinoma syndrome, their presence should suggest fumarate hydratase aberration. Identifying these cases is an important step in the diagnostic workup of patients with possible hereditary leiomyomatosis and renal cell carcinoma.

Hereditary leiomyomatosis and renal cell cancer presenting as metastatic kidney cancer at 18 years of age: implications for surveillance

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an autosomal dominant syndrome characterized by skin piloleiomyomas, uterine leiomyomas and papillary type 2 renal cancer caused by germline mutations in the fumarate hydratase (FH) gene. Previously, we proposed renal imaging for FH mutation carriers starting at the age of 20 years. However, recently an 18-year-old woman from a Dutch family with HLRCC presented with metastatic renal cancer. We describe the patient and family data, evaluate current evidence on renal cancer risk and surveillance in HLRCC and consider the advantages and disadvantages of starting surveillance for renal cancer in childhood. We also discuss the targeted therapies administered to our patient.

Familial renal cancer as an indicator of hereditary leiomyomatosis and renal cell cancer syndrome

Hereditary Leiomyomatosis and Renal Cell Carcinoma (HLRCC) is a hereditary condition which typically presents with cutaneous and uterine leiomyomata. Papillary type II renal cell carcinoma and other less common histologic subtypes of renal cancer have been reported in HLRCC. We describe the case of a 31-year-old man in which the pathology review of his renal carcinoma and a positive family history of renal carcinoma allowed for the identification of a pathogenic mutation in the FH gene (c.698G>A;p.R233H) confirming the diagnosis of HLRCC. Recognition of this syndrome allowed for appropriate surveillance as well as identification of at-risk family members. Pathology review is essential for accurate diagnosis of a hereditary cancer syndrome in the setting of familial renal cancer.

Hereditary leiomyomatosis and renal cell cancer in families referred for fumarate hydratase germline mutation analysis

Heterozygous fumarate hydratase (FH) germline mutations cause hereditary leiomyomatosis and renal cell cancer (HLRCC), an autosomal dominant syndrome characterized by multiple cutaneous piloleiomyomas, uterine leiomyomas and papillary type 2 renal cancer. The main objective of our study was to evaluate clinical and genetic data from families suspected of HLRCC on a nationwide level. All families referred for FH mutation analysis in the Netherlands were assessed. We performed FH sequence analysis and multiplex ligation-dependent probe amplification. Families with similar FH mutations were examined for haplotype sharing. In 14 out of 33 families, we identified 11 different pathogenic FH germline mutations, including 4 novel mutations and 1 whole-gene deletion. Clinical data were available for 35 FH mutation carriers. Cutaneous leiomyomas were present in all FH mutation carriers older than 40 years of age. Eleven out of 21 female FH mutation carriers underwent surgical treatment for symptomatic uterine leiomyomas at an average of 35 years. Two FH mutation carriers had papillary type 2 renal cancer and Wilms' tumour, respectively. We evaluated the relevance of our findings for clinical practice and have proposed clinical diagnostic criteria, indications for FH mutation analysis and recommendations for management.

Mutation screening of fumarate hydratase by multiplex ligation-dependent probe amplification: detection of exonic deletion in a patient with leiomyomatosis and renal cell cancer

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is a syndrome predisposing to cutaneous and uterine leiomyomatosis as well as renal cell cancer and uterine leiomyosarcoma. Heterozygous germline mutations in the fumarate hydratase (FH, fumarase) gene are known to cause HLRCC. On occasion, no FH mutation is detected by direct sequencing, despite the evident HLRCC phenotype in a family. In the present study, to investigate whole gene or exonic deletions and amplifications in FH mutation-negative patients, we used multiplex ligation-dependent probe amplification technology. The study material comprised 7 FH mutation-negative HLRCC patients and 12 patients affected with HLRCC-associated phenotypes, including papillary RCC, early-onset RCC, uterine leiomyomas, or uterine leiomyosarcoma. A novel FH mutation, a deletion of FH exon 1 that encodes the mitochondrial signal peptide, was detected in one of the HLRCC patients (1/7). The patient with the FH mutation displayed numerous painful cutaneous leiomyomas and papillary type renal cell cancer. Our finding, together with the two patients with whole FH gene deletion who had been detected previously, suggests that exonic or whole-gene FH deletions are not a frequent cause of HLRCC syndrome.

Diffuse and segmental variants of cutaneous leiomyomatosis: novel mutations in the fumarate hydratase gene and review of the literature

Multiple cutaneous and uterine leiomyomatosis (MCUL; OMIM 150800) is an autosomal dominantly inherited disease characterized by leiomyomas of the skin and uterine leiomyomas. Recently, association of MCUL with different forms of renal cancer has been described. This syndrome is referred to as hereditary leiomyomatosis and renal cell cancer (OMIM 605839). Both disorders result from heterozygous germline mutations in the fumarate hydratase (FH) gene that may function as a tumor suppressor. Interestingly, cutaneous leiomyomas do not only manifest in a diffuse and symmetric fashion. Rather frequently, a segmental or band-like manifestation pattern can be observed, usually following the lines of Blaschko. Here, we sought to elucidate the molecular basis of diffuse and segmental cutaneous leiomyomatosis in six unrelated Dutch and Spanish patients and their families. We identified six novel FH mutations, including one missense and one nonsense mutation, two deletions and two splice-site mutations. The segmental phenotype that was observed in various patients with FH mutations most likely reflects a type 2 segmental manifestation of cutaneous leiomyomatosis as previously also described for other autosomal dominantly inherited skin diseases. The results presented here extend the current data on the molecular basis of familial cutaneous leiomyomatosis and comprise, to the best of our knowledge, the first genetic study in Dutch and Spanish patients with this disorder. In addition, we review the clinical and molecular aspects of the disease.

Expression of transforming K-Ras oncogene affects mitochondrial function and morphology in mouse fibroblasts

K-ras transformed fibroblasts have been shown to have a stronger dependence from glycolysis, reduced oxidative phosphorylation ability and a fragility towards glucose depletion compared to their immortalized, normal counterparts. In this paper, using RNA profiling assays and metabolic perturbations, we report changes in expression of genes encoding mitochondrial proteins and alterations in mitochondrial morphology that correlate with mitochondrial functionality. In fact, unlike normal cells, transformed cells show reduced ATP content and inability to modify mitochondria morphology upon glucose depletion. Being reverted by GEF-DN expression, such morphological and functional changes are directly connected to Ras activation. Taken together with reported partial mitochondrial uncoupling and more sustained apoptosis of transformed cells, our results indicate that activation of the Ras pathway strikingly impacts on energy and signaling-related aspects of mitochondria functionality, that in turn may affect the terminal phenotype of transformed cells.

Germline fumarate hydratase mutations in patients with ovarian mucinous cystadenoma

Germline mutations in the fumarate hydratase (FH) gene were recently shown to predispose to the dominantly inherited syndrome, hereditary leiomyomatosis and renal cell cancer (HLRCC). HLRCC is characterized by benign leiomyomas of the skin and the uterus, renal cell carcinoma, and uterine leiomyosarcoma. The aim of this study was to identify new families with FH mutations, and to further examine the tumor spectrum associated with FH mutations. FH germline mutations were screened from 89 patients with RCC, skin leiomyomas or ovarian tumors. Subsequently, 13 ovarian and 48 bladder carcinomas were analyzed for somatic FH mutations. Two patients diagnosed with ovarian mucinous cystadenoma (two out of 33, 6%) were found to be FH germline mutation carriers. One of the changes was a novel mutation (Ala231Thr) and the other one (435insAAA) was previously described in FH deficiency families. These results suggest that benign ovarian tumors may be associated with HLRCC.