Cancer spectrum and frequency among children with Noonan, Costello, and cardio-facio-cutaneous syndromes.

BACKGROUND: Somatic mutations affecting components of the Ras-MAPK pathway are a common feature of cancer, whereas germline Ras pathway mutations cause developmental disorders including Noonan, Costello, and cardio-facio-cutaneous syndromes. These 'RASopathies' also represent cancer-prone syndromes, but the quantitative cancer risks remain unknown. METHODS: We investigated the occurrence of childhood cancer including benign and malignant tumours of the central nervous system in a group of 735 individuals with germline mutations in Ras signalling pathway genes by matching their information with the German Childhood Cancer Registry. RESULTS: We observed 12 cases of cancer in the entire RASopathy cohort vs 1.12 expected (based on German population-based incidence rates). This corresponds to a 10.5-fold increased risk of all childhood cancers combined (standardised incidence ratio (SIR)=10.5, 95% confidence interval=5.4-18.3). The specific cancers included juvenile myelomonocytic leukaemia=4; brain tumour=3; acute lymphoblastic leukaemia=2; rhabdomyosarcoma=2; and neuroblastoma=1. The childhood cancer SIR in Noonan syndrome patients was 8.1, whereas that for Costello syndrome patients was 42.4. CONCLUSIONS: These data comprise the first quantitative evidence documenting that the germline mutations in Ras signalling pathway genes are associated with increased risks of both childhood leukaemia and solid tumours.

[Middle ear salivary gland choristoma related to branchio-oto-renal syndrome diagnosed by array-CGH]. / Speicheldrüsenchoristom im Mittelohr bei mittels Array-CGH diagnostiziertem branchiootorenalem Syndrom.

Branchio-oto-renal (BOR) syndrome is characterized by ear malformations associated with sensorineural or mixed hearing loss. In addition, preauricular tags, preauricular pits, branchial cleft fistulas and cysts, as well as renal dysplasia are seen. A genetic mutation on chromosome 8, either autosomal dominantly inherited or occuring as a spontaneous mutation, is the cause in the majority of cases. Using array-based comparative genomic hybridization (CGH), it is possible to detect even the smallest genetic changes. Salivary gland choristoma in the middle ear is very rare. Surgical removal and histological clarification are required.

Phenotypic spectrum of epidermolysis bullosa associated with α6ß4 integrin mutations.

BACKGROUND: Integrin α6ß4 is a transmembrane receptor and a key component of the hemidesmosome anchoring complex. It is involved in cell-matrix adhesion and signalling in various tissues. Mutations in the ITGA6 and ITGB4 genes coding for α6ß4 integrin compromise dermal-epidermal adhesion and are associated with skin blistering and pyloric atresia (PA), a disorder known as epidermolysis bullosa with PA (EB-PA). OBJECTIVES: To elucidate the molecular pathology of skin fragility in eight cases, disclose the underlying ITGA6 and ITGB4 mutations and study genotype-phenotype correlations. METHODS: DNA was isolated from ethylenediaminetetraacetic acid-blood samples, and the coding exons and exon-intron boundaries of ITGA6 and ITGB4 were amplified by polymerase chain reaction (PCR), and directly sequenced. Skin samples were submitted to immunofluorescence mapping with antibodies to adhesion proteins of the dermal-epidermal junction. Primary keratinocytes were isolated, and used for RNA and protein extraction, reverse transcription PCR and immunoblotting. Ultrastructural analysis of the skin was performed in one patient. RESULTS: We disclose 10 novel mutations, one in ITGA6 and nine in ITGB4. Skin cleavage was either intraepidermal or junctional. Lethal outcome and PA correlated with loss-of-function mutations in two cases. Solely mild skin involvement was associated with deletion of the C-terminus of ß4 integrin. Combinations of missense, nonsense or frameshift mutations caused severe urinary tract involvement in addition to skin fragility in five cases. CONCLUSIONS: The present study reveals novel ITGA6 and ITGB4 gene mutations and supports previous reports showing that the phenotype may lack PA and be limited to skin and nail involvement. In four out of six cases of EB-PA, life expectancy was not impaired. A high frequency of urinary tract involvement was found in this study, and represented the main cause of morbidity. Low levels of ß4 integrin expression were compatible with hemidesmosomal integrity and a mild skin phenotype.

CHD7 mutations causing CHARGE syndrome are predominantly of paternal origin.

CHARGE (coloboma, heart defects, atresia of the choanae, retarded growth and development, genital hypoplasia, ear anomalies and deafness) syndrome is a congenital malformation syndrome caused by mutations in the CHD7 gene in approximately 2/3 of cases. In the vast majority of cases, CHARGE syndrome is sporadic. There are only a few reports of parent-to-child transmission and somatic or gonadal mosaicism. To determine the parental origin of CHD7 mutations in sporadic CHARGE syndrome, we screened 30 families for informative exonic or intronic polymorphisms located near the detected CHD7 mutation. An informative polymorphism could be identified in 13 out of 30 families. Linkage analysis was performed between the CHD7 mutation and the polymorphism in the child. In 12 out of 13 families, the mutation affected the paternal allele (92.3%). In our cohort, the mean paternal age at birth was 32.92 years. Comparing the age of fathers of an affected CHARGE patient with the paternal age of the German population in general, we could not observe any paternal age effect. Taken together, we show in this study that de novo CHD7 mutations occur predominantly in the male germ line.

Lethal junctional epidermolysis bullosa with pyloric atresia due to compound heterozygosity for two novel mutations in the integrin ß4 gene.

BACKGROUND: Junctional epidermolysis bullosa with pyloric atresia (JEB-PA) is a rare autosomal recessive disease with blister formation within the lamina lucida due to mutations in the integrin ß4 (ITGB4) and α6 (ITGA6) genes. CASE REPORT: A female preterm infant, first child of healthy non-consanguineous parents, was born at 26 + 4 weeks of gestation by caesarean section, following polyhydramnion and abruption of placenta. She presented with extensive areas of denuded skin on both lateral sides of the head, neck and extremities. Auricles were hypoplastic. Abdominal ultrasound and X-ray were suggestive of pyloric atresia which was revised surgically on the 4th day of life. Further course was complicated by progressive skin detachment, sepsis, and renal insufficiency with fatal outcome at 18 days of age. Immunofluorescence mapping of cryopreserved skin showed junctional cleft formation with negative staining for integrin α6 and integrin ß4. Mutational analysis disclosed compound heterozygosity for two novel nonsense mutations in the ITGB4 gene: c.600dupC/p.F201fsX14 and c.2533C>T/p.Q845X. 2 subsequent pregnancies were terminated following prenatal diagnosis disclosing the same ITGB4 mutations, a 4th pregnancy was unaffected. CONCLUSION: We describe a case of lethal JEB-PA with negative immunoreactivity to integrin α6 and integrin ß4 predicting a poor outcome. Identification of compound heterozygosity for two novel ITGB4 mutations in the affected preterm infant permitted prenatal diagnosis and finally birth of a healthy sibling.

Late-onset inversa recessive dystrophic epidermolysis bullosa caused by glycine substitutions in collagen type VII.

Dystrophic epidermolysis bullosa (DEB) is a rare hereditary skin disorder caused by mutations in COL7A1, encoding collagen type VII.1 Clinical manifestations of COL7A1 mutations range from generalized skin blistering to mild localized blistering or nail dystrophy.2 The investigation of the molecular basis of DEB has revealed more than 540 different mutations that cannot entirely explain phenotypic variations (HGMD Professional 2010.3, https://portal.biobase-international. com/hgmd/). Inversa recessive DEB (RDEB-I) is a subtype characterized by generalized blistering in the neonatal period. The condition improves with age, and in adults blistering is restricted to intertriginous areas, and severe lesions of the oral and genital mucosa and nail changes occur in the majority of described patients.2 Recent data suggested that amino-acid substitutions affecting arginines or glycines at borders of collagenic subdomains might cause this phenotype.3 We report a German patient with an unusually mild RDEB-I harbouring compound heterozygous mutations in COL7A1.

Mild clinical phenotype of Kindler syndrome associated with late diagnosis and skin cancer.

Kindler syndrome (KS) is a heritable skin disorder with a complex phenotype consisting of congenital skin blistering, photosensitivity, progressive generalized poikiloderma and extensive skin atrophy. Here we describe 2 siblings with KS, who are, to the best of our knowledge, the oldest patients reported so far in the literature. The diagnosis was established in their seventh and eighth decades of life, and confirmed by mutation analysis. Both patients were homozygous for the recurrent FERMT1 mutation, c.328C→T, p.R110X. Because of a relatively mild course of the disease, mucosal membranes in the eyes and oesophagus being predominantly affected in recent years, they had been treated under other diagnoses, such as scleroderma. Cutaneous precancerous lesions and epithelial skin cancer arose in both siblings after the age of 50 years and were treated in an early stage. Taken together, we describe the natural course of KS, the morphological abnormalities occurring in the skin of older KS patients, we discuss the differential diagnosis and the association between KS and squamous cell carcinoma.

Poikiloderma with neutropenia: a novel C16orf57 mutation and clinical diagnostic criteria.

A new syndrome with poikiloderma was described by Clericuzio et al. in 1991.(1) They reported 14 Navajo native Americans, including eight siblings, developing in the first year of life an erythematous rash, which started on the limbs and spread over the trunk and the face. This rash evolved into poikiloderma. All patients had recurrent bacterial infections. First published as Navajo poikiloderma this syndrome is now known as poikiloderma with neutropenia (PN, OMIM 604173). The inheritance is autosomal recessive, and mutations in a new gene, C16orf57, were recently described in two kindreds.(2) Because of the phenotypic overlap between Rothmund-Thomson syndrome (RTS) and PN, a few patients have been reclassified as mutations in the RECQL4 gene for RTS were absent.(2-5) Until now 27 patients have been described with clinical PN.(1-3,5-8) Here, we report the sixth family with PN outside the Navajo population. We found the previously unreported mutation c.243G>A, p.W81X in the C16orf57 gene, thus confirming the relation of this gene to the disease.(2,6) Because the molecular genetic diagnosis is not always available, we propose clinical and laboratory diagnostic criteria for PN.

[Glycogenosis type IV (Andersen disease). Clinical data, pathology, and genetics in a fatal perinatal case]. / Glykogenose Typ IV (Andersen). Klinik, Pathologie und Genetik eines letalen perinatalen Falles.

Here we report the case of a newborn with glycogenosis type IV (Andersen disease), who died shortly after birth. The diagnosis was established in the first instance by light microscopy and histochemistry, and subsequently ultrastructurally. DNA could be extracted from a fibroblast cell culture by sequencing the causative GBE1 gene (glycogen branching enzyme 1). Two compound heterozygous mutations in the gene were identified. The differential diagnosis should include Lafora disease as well as polyglucosan body disease. Since there is no effective therapy for glycogenosis type IV to date, prenatal diagnosis is mandatory.

Multiple malignant diseases in a patient with Rothmund-Thomson syndrome with RECQL4 mutations: Case report and literature review.

RECQL4 mutations cause genetic instability and increase the risk of malignant disease. We report on a patient with compound heterozygosity for two novel RECQL4 mutations: mutation c.1919_1924delTCACAG, p.L640_A642delinsP in exon 12 of the RECQL4 gene and mutation c.1704+1G>A in intron 10 of the RECQL4 gene. He subsequently developed large cell anaplastic T cell lymphoma at the age of 9 years, diffuse large cell B lymphoma and osteosarcoma when he was 14 years old, and finally acute lymphatic leukemia when he was 21 years old. The most remarkable clinical features are young age, spontaneous remission of diffuse large cell lymphoma, and severe CNS and skin toxicity of cytotoxic treatment.

Identification of novel and known KRT5 and KRT14 mutations in 53 patients with epidermolysis bullosa simplex: correlation between genotype and phenotype.

BACKGROUND: Basal epidermolysis bullosa simplex (EBS) is a hereditary skin blistering disorder resulting in most cases from missense mutations in the keratin 5 (KRT5) or keratin 14 (KRT14) genes. OBJECTIVES: To identify the underlying mutations in different EBS subtypes and correlate genotype and phenotype. METHODS: Mutation analysis was performed in 53 patients with EBS and their families by direct sequencing of the KRT5 and KRT14 genes. RESULTS: We identified 39 different mutations, of which 15 have not been published previously. Three novel deletion/insertion mutations, among them one in-frame duplication, were associated with the rare phenotype of EBS with mottled pigmentation. We identified for the first time a patient with compound heterozygosity for KRT5 mutations causing Dowling-Degos disease and EBS. CONCLUSIONS: Identification of novel mutations and genotype-phenotype correlations in EBS allow improved understanding of disease pathogenesis as well as better patient management.

Severe phenotype in a girl with partial tetrasomy 7, karyotype 46,XX,trp(7)(q35q36).

On prenatal ultrasonography, polyhydramnion, internal hydrocephalus, hypoplasia of the corpus callosum, and dysmorphic features were detected in a fetus of a 22-year-old mother. Subsequent karyotyping of amniocytes revealed supernumerary material in distal 7q. The baby was delivered after 38+4 weeks of gestation, and postnatal array CGH analysis showed a triplication of 7q35-->q36, resulting in partial tetrasomy. The triplication was not distinguishable from a duplication by conventional and molecular cytogenetic methods, but was clearly identified by array CGH analysis. The phenotype was rather severe with limited cardiac contractility and subsequent respiratory problems, as well as progressive neurologic deterioration and several dysmorphic features. Triplications in general are rare, and this case is the first report of a microscopically visible triplication in 7q. Duplication patients of the same chromosomal segment also showed a severe phenotype, however, in our opinion there are no common features suggesting a clinically recognizable distal 7q duplication/triplication syndrome.

Forty-two novel COL7A1 mutations and the role of a frequent single nucleotide polymorphism in the MMP1 promoter in modulation of disease severity in a large European dystrophic epidermolysis bullosa cohort.

BACKGROUND: Dystrophic epidermolysis bullosa (DEB) is a severe genetic skin blistering disorder caused by mutations in the gene COL7A1, encoding collagen VII. Recently, the MMP1 promoter single nucleotide polymorphism (SNP) rs1799750, designated as 1G 2G, was shown to be involved in modulation of disease severity in patients with recessive DEB (RDEB), and was proposed as a genetic modifier. OBJECTIVES: To identify the molecular basis of DEB in 103 individuals and to replicate the results of the MMP1 promoter SNP analysis in an independent patient group, as verification is necessary in such a rare and heterogeneous disorder. METHODS: To determine the molecular basis of the disease, we performed COL7A1 mutation screening, reverse transcription-polymerase chain reaction (PCR) and real-time quantitative PCR. The status of the MMP1 SNP was analysed by PCR and restriction enzyme digestion and verified by sequencing. RESULTS: We disclosed 42 novel COL7A1 mutations, including the first large genomic deletion of 4 kb affecting only the COL7A1 gene, and three apparently silent mutations affecting splicing. Even though the frequency of the high-risk allele was increased in patients with RDEB, no statistically significant correlation between disease severity and genotype could be made. Also, no correlation was observed with development of squamous cell carcinoma, a severe complication of DEB. CONCLUSIONS: Taken together, the results suggest that the MMP1 SNP is not the sole disease modifier in different forms of DEB, and other genetic and environmental factors contribute to the clinical phenotype.

[Hereditary Alzheimer's disease with amyloid angiopathy caused by amyloid precursor protein locus]. / Familiäre Alzheimer-Variante mit Amyloidangiopathie als Ausdruck einer APP-Gen-Duplikation.

We report a patient with early-onset autosomal dominant dementia. The CSF showed increased levels of tau protein and decreased amyloid beta (ratio 42:40) typical for Alzheimer's disease. Cerebral MRI revealed vascular lesions and white-matter changes around the posterior horns of the ventricles with only moderate atrophy of the brain. Susceptibility-weighted imaging detected multiple small hemorrhagic changes. Gene analysis revealed amyloid precursor protein (APP) locus duplication as the cause of hereditary Alzheimer's dementia. The co-occurrence of CSF changes typical for Alzheimer's disease and MRI findings of cerebral amyloid angiopathy is remarkable, as it is also described for APP locus duplication. In conjunction with a family history suggestive of hereditary dementia, such a constellation should lead to enhanced gene analysis.

Biallelic loss of function of the promyelocytic leukaemia zinc finger (PLZF) gene causes severe skeletal defects and genital hypoplasia.

BACKGROUND: Deletions of 11q23 are associated with mental retardation, craniofacial dysmorphism, microcephaly and short stature. We present a patient with similar clinical findings, in addition to absence of the thumbs, hypoplasia of the radii and ulnae, additional vertebrae and ribs, retarded bone age and genital hypoplasia. METHODS: Genomic DNA from the patient was screened for chromosomal imbalances by array-based comparative genomic hybridisation. DNA sequence analyses and reporter gene assays were performed in order to identify candidate gene mutations. RESULTS: The patient has an approximately 8 Mbp de novo deletion on the paternal chromosome 11, which includes the promyelocytic leukaemia zinc-finger gene (PLZF, ZBTB16; OMIM 176797). The maternal PLZF allele harbours a recessive missense mutation (c.1849A-->G), which leads to the substitution of a highly conserved methionine by valine (p.Met617Val) within a zinc-finger motif. Taking into account specific alpha-helical propensities of Val and Met, this mutation is likely to destabilise the alpha helix of the zinc finger that forms the contact with the DNA duplex, thus affecting the biological function as shown by reporter-gene assays. DISCUSSION: The PLZF gene is one of five partners fused to the retinoic acid receptor alpha in acute promyelocytic leukaemia. We describe the first patient, to our knowledge, with a germline mutation of PLZF. Our findings as well as observations in Plzf-deficient mice indicate that PLZF is a key regulator of skeletal and male germline development. Furthermore, this case highlights the importance of searching for a recessive mutation on the non-deleted chromosome in patients with a microdeletion and atypical clinical findings.

C-terminally truncated kindlin-1 leads to abnormal adhesion and migration of keratinocytes.

BACKGROUND: The Kindler syndrome (KS) protein kindlin-1 is a member of a protein complex that links cortical actin to integrins on the surface of basal keratinocytes. Loss of kindlin-1 leads to abnormalities of cell adhesion and motility, and to skin blistering and progressive poikiloderma as clinical symptoms. OBJECTIVES: Here we investigated a severely affected patient, disclosed the mutation that caused the disease and delineated its biological consequences. METHODS: Mutation screening of the kindlin-1 gene, KIND1 (now called FERMT1), was performed with polymerase chain reaction (PCR) amplification of all exons and sequencing. Mutated kindlin-1 was characterized by reverse transcriptase (RT)-PCR and immunoblotting, and genotype-phenotype correlations were analysed using immunohistochemical staining of skin biopsies and keratinocytes from the patient's skin. Cell adhesion and motility were assessed with functional tests. RESULTS: We disclosed a splice site mutation in the first position of intron 13 of the FERMT1 gene, which caused skipping of exon 13. The short transcript partially escaped nonsense-mediated mRNA decay and was translated into a truncated protein. CONCLUSION: A C-terminally truncated kindlin-1 in keratinocytes could not function correctly even if it were expressed.

Dystrophic epidermolysis bullosa pruriginosa is not associated with frequent FLG gene mutations.

BACKGROUND: Dystrophic epidermolysis bullosa pruriginosa (DEB-Pr; OMIM 604129) is a rare manifestation of dystrophic epidermolysis bullosa (DEB), characterized by pruritus, nodular prurigo-like lesions and fragility of the skin mainly in the extremities. Fewer than 40 patients with autosomal dominant or recessive inheritance, or sporadic DEB-Pr, have been described in the literature. OBJECTIVES: To disclose mutations in DEB-Pr and to elucidate the role of other pathogenic factors which may influence the pruriginous phenotype. METHODS: Seven patients with typical clinical features of DEB-Pr were studied. RESULTS: In all patients, mutations in the gene encoding collagen VII (COL7A1) were disclosed, two of them novel (p.G2623V, p.E2736K). Three mutations were dominant, three recessive and one de novo. In the families with dominant DEB there were one or more members with DEB-Pr, but also at least one affected sibling who did not develop DEB-Pr. In six of seven patients, the clinical history revealed factors that initially induced pruritus, such as atopy, pregnancy, thyroid hormone imbalance, diabetes, infections and contact sensitization. Common filaggrin mutations were ruled out in all patients and normal filaggrin staining was found in the skin samples. CONCLUSIONS: DEB-Pr develops as a result of COL7A1 gene mutations and acquired phenotype-modifying factors. Filaggrin mutations did not contribute to the pruriginous phenotype in the present patient cohort.