New Mutations Associated with Rasopathies in a Central European Population and Genotype-Phenotype Correlations.

We performed the genetic analysis of Rasopathy syndromes in patients from Central European by direct sequencing followed by next generation sequencing of genes associated with Rasopathies. All 51 patients harboured the typical features of Rasopathy syndromes. Thirty-five mutations were identified in the examined patients (22 in PTPN11, two in SOS1, one in RIT1, one in SHOC2, two in HRAS, three in BRAF, two in MAP2K1 and two in the NF1 gene). Two of them (p.Gly392Glu in the BRAF gene and p.Gln164Lys in the MAP2K1 gene) were novel with a potentially pathogenic effect on the structure of these proteins. Statistically significant differences in the presence of pulmonary stenosis (63.64% vs. 23.81%, P = 0.013897) and cryptorchidism (76.47% vs. 30%, P = 0.040224) were identified as the result of comparison of the prevalence of phenotypic features in patients with the phenotype of Noonan syndrome and mutation in the PTPN11 gene, with the prevalence of the same features in patients without PTPN11 mutation. Cryptorchidism as a statistically significant feature in our patients with PTPN11 mutation was not reported as significant in other European countries (Germany, Italy and Greece). The majority of mutations were clustered in exons 3 (45.45%), 8 (22.73%), and 13 (22.73%) of the PTPN11 gene.

Late onset of familial neurogenic diabetes insipidus in monozygotic twins.

OBJECTIVE: Autosomal dominant familial diabetes insipidus (FNDI) is a rare disease characterized by polydipsia and polyuria due to deficiency of the antidiuretic hormone, arginine vasopressin (AVP). We report the first Slovak family with the disease. Noteworthy is the concordantly belated debut of the disease symptoms in two monozygotic twin proband girls in the age of 17 years. Because of inconclusive results of water deprivation test consistent with partial diabetes insipidus (DI), missing "bright spot" of posterior pituitary gland in T1-weighted magnetic resonance imaging and family occurrence of polyuria and polydipsia on anamnestic evaluation. METHODS: Molecular genetic testing of the AVP gene was proceeded, because of the inconclusive results of water deprivation test consistent with partial diabetes insipidus, missing "bright spot" of posterior pituitary gland in T1-weighted magnetic resonance imaging and family occurrence of polyuria and polydipsia on anamnestic evaluation. RESULTS: Genetic analysis revealed a heterozygous g.279G>A substitution that predicts a p.Ala19Thr substitution in the signal peptide of the AVP prohormone. The wide intrafamiliar variations (3 to 17 years) in disease onset together with the concordantly delayed debut of polyuria in two monozygotic twin girls suggest that individual differences in genetic influences family environmental factors may modify the penetrance of the mutation of the AVP gene. CONCLUSIONS: The present paper supports the notion that molecular genetic evaluation should be performed in all patients with familial occurrence of DI regardless of the clinical results.

Rasopathies - dysmorphic syndromes with short stature and risk of malignancy.

OBJECTIVES: The term ´Rasopathies´ represents a group of five neurodevelopmental syndromes (Noonan, LEOPARD, Costello, Cardio-facio-cutaneous, and Neurofibromatose-Noonan syndrome) caused by germline mutation in genes encoding proteins involved in RAS/MAPK (rat sarcoma/mitogen-activated protein kinase) signaling pathway. The RAS/MAPK signaling pathway participates in regulation of cell determination, proliferation, differentiation, migration, and senescence and dysregulation of this pathway can lead to the risk of tumorigenesis. In this review, we aim to summarize the current clinical and molecular genetic knowledge on Rasopathies with special attention for the risk of cancer. We propose also clinical and therapeutic approach for patients with malignancy. METHODS: We are reviewing the clinical and molecular basis of Rasopathies based on recent studies, clinical examination, and molecular diagnostics (mutation analysis of causal genes for Rasopathies) in Slovak pediatric patients. RESULTS: Some clinical features, such as short stature, a specific facial dysmorphology and cardiac abnormalities are common to all of Rasopathy syndromes. However, there are unique signs by which the syndromes can differ from each other, especially multiple lentigo in LEOPARD syndrome, increased risk of malignancy in Costello syndrome, dry hyperkeratotic skin in patients with cardio-facio-cutaneous syndrome, and neurofibromas and cafe-au-lait spots in neurofibromatosis-Noonan syndrome. CONCLUSION: Despite the overlapping clinical features, Rasopathy syndromes exhibit unique fenotypical features and the precise molecular diagnostics may lead to confirmation of each syndrome. The molecular diagnostics may allow the detection of pathogenic mutation associated with tumorigenesis.

[Clinical dysmorphic syndromes with tumorigenesis]. / Klinické dysmorfické syndrómy s tumorigenézou.

Genetic alterations cause predisposition to malignancy by increased cancer risk related to constitutional mutations in growth-regulating or DNA repair genes. Some pediatric malignancies are associated with dysmorphic features in several body areas. Through physical examination, we recognise characteristic signs of genetic dysmorphic disorders, such as somatic overgrowth, undergrowth, macrocephaly, microcephaly and dysmorphic changes of the face, eyes, mouth and lips, heart, gastrointestinal tract, urinary tract, genitalia and skeleton. Recognition of a cancer-associated dysmorphic syndrome allows intensive cancer screening and genetic counseling. Therefore, it is recommended that every child with cancer should be examined by a clinical geneticist. Molecular diagnostics of germinal mutations may very effectively detect families at high risk of malignancy and help provide primary prevention. This work presents clinical syndromes with genetic background and cancer screening recommendations for 18 syndromes with increased cancer risk.