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.

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.

Novel germline mutation in the transmembrane region of RET gene close to Cys634Ser mutation associated with MEN 2A syndrome.

Two mutations on the same allele of RET gene were revealed in a family with predisposition to multiple endocrine neoplasia (MEN) type 2A. The first mutation changes codon 634 from cysteine to serine. The second, a novel mutation in codon 641, changes alanine to serine in the transmembrane domain of the RET protein. Two mutations were present in close proximity in both the patients' germline and tumor DNA and were absent in DNA isolated from healthy family members and control blood donors. All MEN 2A affected family members suffered from medullary thyroid carcinoma and two of ten patients for pheochromocytoma. No parathyroid gland alterations were observed in patients with two RET gene mutations. Analysis of four genetic polymorphisms in the RET gene showed higher incidence of polymorphisms of exons 11 and 15. The observed allelic imbalance in favor of mutated allele in pheochromocytoma corresponded to higher expression of the RET gene. These observations confirm the multifactorial process leading to development of MEN 2A syndrome.

Thyroid hormone metabolism in pediatric cardiac patients treated by continuous povidone-iodine irrigation for deep sternal wound infection.

OBJECTIVE: The purpose of this study was to assess the influence of povidone-iodine mediastinal irrigation used for the treatment of deep sternal wound infection (DSWI) on thyroid function. METHODS: Thyroid function was studied in 18 pediatric cardiac patients treated with continuous povidone-iodine irrigation for DSWI. The median age of patients was 8 months (18 days-5.3 years). Serum concentrations of total triiodothyronine (TT3), total thyroxine (TT4), free triiodothyronine (FT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), reverse triiodothyronine (rT3) and thyroxine-binding globulin (TBG) were measured at three time points: (a) prior to mediastinal reexploration (before povidone-iodine exposure); (b) immediately after discontinuation of povidone-iodine irrigation; (c) 2 weeks after discontinuation of mediastinal irrigation. Urinary iodine excretion was examined on the last day of povidone-iodine exposure. RESULTS: Prior to the mediastinal reexploration, the median TT3 and TT4 levels were below the normal range, then increased significantly to concentrations within the normal range. The median serum FT3 levels were within the normal range throughout the observation period, though a significant increase of FT3 levels was observed after discontinuation of irrigation. The median serum FT4 concentrations were within the normal range prior to irrigation and did not change significantly. The median rT3 levels were within the normal range, close to upper normal limit. The median TBG levels were within the normal range throughout the observation period, though a significant increase of TBG levels was observed during the period of mediastinal irrigation. The median TSH level was within the normal range prior to mediastinal irrigation and did not change significantly. Urinary iodine concentrations in infants with povidone-iodine irrigation were significantly higher 6700 microg/l (range, 1600-15000 microg/l) than in the group of 53 healthy infants 200 microg/l (range, 20-780 microg/l, P<0,001). CONCLUSIONS: Our data showed that the use of povidone-iodine irrigation in the patients with DSWI has not lead to any significant alteration in thyroid function within the study period.

[Growth and puberty in children after treatment of acute lymphoblastic leukemia]. / Rast a puberta u detí po liecbe akútnej lymfoblastickej leukémie.

BACKGROUND: Growth retardation and other endocrine abnormalities were recognized as sequelae of therapy of acute lymphoblastic leukemia (ALL), especially when chemotherapy was combined with cranial irradiation. The aim of our study was to establish growth and pubertal development in the group of children who had been previously successfully treated for ALL. METHODS AND RESULTS: 58 children (30 F, 28 M, age 8-18 y.) in complete initial remission lasting 4-15 y. (m 8 y.) after standard antileukemic therapy (including cranial irradiation) completed 2-9 y. ago (m 3 including y.) were studied. Standard deviation score (SDS) of standing height (SH) to chronological age (CA) and to genetic target height (GTH), index of body proportionality and timing of puberty were followed up. The final height attained 21 girls and 3 boys. The height of the boys differed neither from the average for our men, nor from their GTH. Girls: SH 148 cm-169 cm, SH of 7 girls > or = -1.5 SDS, 8 girls > or = -1.5 SDS to their GTH. The final height didn't reach yet 23 boys and 9 girls. Their SH to CA as well as SH to GTH didn't substantially differ from average. Index of body proportionality > or = 1.5 SDS in 12/30 girls and 6/28 boys. Menarche was already reached in 25 girls in age ranging from 10-15 y. (mean 11.3 y.), what was less than average for our population (13.3 y.). CONCLUSION: Even the height of prepubertal children under study didn't differ from average, the final height of girls (boys could not be evaluated because of small numbers) was significantly lower as could be expected. We suppose the early ending of puberty as a contributing factor of short stature in girls. Clear tendency to obesity especially among older girls was observed. Children who underwent antileukemic therapy deserve careful endocrinological follow-up.

Early diagnosis of medullary thyroid carcinoma in a 13 years old girl.

Early stage of medullary thyroid carcinoma was diagnosed in a 13 years old girl from the family with incidence of MEN IIa. High level of calcitonin after pentagastrin stimulation was crucial for the diagnosis. Pentagastrin test as a regular screening for medullary thyroid carcinoma for all children over 3 years of families with MEN IIa is recommended.

Our experience with childhood histiocytosis X.

A retrospective analysis of the course of histiocytosis X in 16 children treated at our hospital over the past 15 years is presented. Nearly all of the patients were at generalized stages of the disease. In this study the staging according to Greenberg was used. The disease had a favorable course at Stages I and II, 1 patient at Stage III and 2 at Stage IV died. All the children were treated by chemotherapy, in some of them combined with radiotherapy. Individual patients differed from one another with respect to chemotherapeutic regimens. The actuarial survival rate was 78% for the whole group. Better results were obtained after a less intense but long-term treatment than after an intense but interrupted chemotherapy.