High-Resolution Melting Analysis for Rapid Detection of Mutations in Patients with FGFR3-Related Skeletal Dysplasias.

Background: Mutations in the fibroblast growth factor receptor 3 (FGFR3) gene are related to skeletal dysplasias (SDs): acondroplasia (ACH), hypochodroplasia (HCH) and type I (TDI) and II (TDII) tanatophoric dysplasias. This study was designed to standardize and implement a high-resolution melting (HRM) technique to identify mutations in patients with these phenotypes. Methods: Initially, FGFR3 gene segments from 84 patients were PCR amplified and subjected to Sanger sequencing. Samples from 29 patients positive for mutations were analyzed by HRM. Results: Twelve of the patients FGFR3 mutations had ACH (six g.16081 G > A, three g.16081 G > C and three g.16081 G > A + g.16002 C > T); thirteen of patients with HCH had FGFR3 mutations (eight g.17333 C > A, five g.17333 C > G and five were negative); and four patients with DTI had FGFR3 mutations (three g.13526 C > T and one g.16051G > T and two patients with DTII (presented mutation g.17852 A > G). When analyzing the four SDs altogether, an overlap of the dissociation curves was observed, making genotyping difficult. When analyzed separately, however, the HRM analysis method proved to be efficient for discriminating among the mutations for each SD type, except for those patients carrying additional polymorphism concomitant to the recurrent mutation. Conclusion: We conclude that for recurrent mutations in the FGFR3 gene, that the HRM technique can be used as a faster, reliable and less expensive genotyping routine for the diagnosis of these pathologies than Sanger sequencing.

Novel and Recurrent Mutations in the FGFR3 Gene and Double Heterozygosity Cases in a Cohort of Brazilian Patients with Skeletal Dysplasia.

Mutations in the fibroblast growth factor receptor 3 gene (FGFR3) cause achondroplasia (ACH), hypochondroplasia (HCH), and thanatophoric dysplasia types I and II (TDI/TDII). In this study, we performed a genetic study of 123 Brazilian patients with these phenotypes. Mutation hotspots of the FGFR3 gene were PCR amplified and sequenced. All cases had recurrent mutations related to ACH, HCH, TDI or TDII, except for 2 patients. One of them had a classical TDI phenotype but a typical ACH mutation (c.1138G>A) in combination with a novel c.1130T>C mutation predicted as being pathogenic. The presence of the second c.1130T>C mutation likely explained the more severe phenotype. Another atypical patient presented with a compound phenotype that resulted from a combination of ACH and X-linked spondyloepiphyseal dysplasia tarda (OMIM 313400). Next-generation sequencing of this patient's DNA showed double heterozygosity for a typical de novo ACH c.1138G>A mutation and a maternally inherited TRAPPC2 c.6del mutation. All mutations were confirmed by Sanger sequencing. A pilot study using high-resolution melting (HRM) technique was also performed to confirm several mutations identified through sequencing. We concluded that for recurrent FGFR3 mutations, HRM can be used as a faster, reliable, and less expensive genotyping test than Sanger sequencing.

Early hematopoietic stem cell transplantation in a patient with severe mucopolysaccharidosis II: A 7 years follow-up.

Mucopolysaccharidosis type II (MPS II - Hunter syndrome) is an X-linked lysosomal storage disorder caused by a deficiency in the enzyme iduronate-2 sulfatase (I2S), leading to the accumulation of the glycosaminoglycans, affecting multiple organs and systems. Enzyme replacement therapy does not cross the blood brain barrier, limiting results in neurological forms of the disease. Another option of treatment for severe MPS, hematopoietic stem cell transplantation (HSCT) has become the treatment of choice for the severe form of MPS type I, since it can preserve neurocognition when performed early in the course of the disease. To date, only few studies have examined the long-term outcomes of HSCT in patients with MPS II. We describe the seven-year follow-up of a prenatally diagnosed MPS II boy with positive family history of severe MPS form, submitted to HSCT with umbilical cord blood cells at 70 days of age. Engraftment after 30 days revealed mixed chimerism with 79% donor cells; after 7 years engraftment remains at 80%. I2S activity 30 days post-transplant was low in plasma and normal in leukocytes and the same pattern is observed to date. At age 7 years growth charts are normal and he is very healthy, although mild signs of dysostosis multiplex are present, as well as hearing loss. The neuropsychological evaluation (Wechsler Intelligence Scale for Children - Fourth Edition - WISC-IV), disclosed an IQ of 47. Despite this low measured IQ, the patient continues to show improvements in cognitive, language and motor skills, being quite functional. We believe that HSCT is a therapeutic option for MPS II patients with the severe phenotype, as it could preserve neurocognition or even halt neurodegeneration, provided strict selection criteria are followed.

Identification of familial clustering for cancer through the family health strategy program in the municipality of Angra dos Reis, Rio de Janeiro, Brazil.

Identification of families with history of cancer in the municipality of Angra dos Reis, Rio de Janeiro (Brazil), through the Brazilian Unified Primary Health Care System was explored based in the Community Health Agents (CHA) program. This study was divided into two phases: a descriptive one with a cross-sectional epidemiological data of families with history of cancer based on CHA-collected data from home visits in four primary health care units. The second phase consisted in identifying familial clustering of three or more individuals with cancer through construction of a three-generation pedigree and revisited by an itinerant group of medical geneticists. Genetic counseling was carried out with the intent of selecting potential families at risk for hereditary familial cancers. In the first phase of the study, 1,581 families were interviewed by the CHA at their homes. A positive history for cancer was present in 42.3 % of families, comprising 22.3 % with only one case per family, 11.2 % with two cases, and 8.6 % with three or more cases in the family. The informant reported that 15 % of the cases were from the father lineage, 12 % from the mother lineage, and 12.1 % within siblings. In the remaining 60.9 % families, cancer was present in both sides of the family. The types of cancer reported were uterus 8.7 % (n = 137), stomach 7.7 % (n = 122), breast 6.9 % (n = 109), throat 6.8 % (n = 99), prostate 5.4 % (n = 85), lung 5.6 % (n = 88), bowel 3.7 % (n = 59), and unspecified sites in 6.8 % (n = 108) of families. No statistical differences were noted between the data collected on each primary care unit. In the second phase of the study, 136 families (2.9 %) from the total of families interviewed in phase 1 were selected due to the presence of three or more individuals with cancer in the family. Among those, only 73 families attended genetic counseling. Comparison between the data obtained by the CHA and the medical geneticists shows complete agreement in 36 cases (49.3 %), partial agreement in 25 cases (34.2 %) with more detailed information in the CHA sheets, discordance in 4 cases (5.5 %), and not possible to correlate in 8 cases due to identification inconsistency. Risk assessment for cancer was calculated based on the criteria adopted by Scheuner et al. (Genet Med 12(11):726-735, 2010) and revealed that 50.0 % of the families were classified as having a weak risk, 36.1 % a moderate risk, and 13.8 % were considered of high risk. Concerning known hereditary cancer syndromes, we found one family that met the criteria for breast and ovary hereditary cancer (1.4 %) and one family with non-polyposis hereditary colon cancer as revised by Bethesda protocol. Such preliminary results indicated that the Brazilian Primary Health Care system based on the CHA framework can be an effective entrance into the Unified Brazilian Health Care System (SUS-Brazil) for individuals with genetically determined diseases, such as familial cancer. Families with a history of three or more cases of cancer and considered of high risk for familial cancer could be referred to a tertiary health center for proper oncogenetic counseling.

A new multicolor fluorescence in situ hybridization probe set directed against human heterochromatin: HCM-FISH.

A new multicolor fluorescence in situ hybridization (mFISH) probe set is presented, and its possible applications are highlighted in 25 clinical cases. The so-called heterochromatin-M-FISH (HCM-FISH) probe set enables a one-step characterization of the large heterochromatic regions within the human genome. HCM-FISH closes a gap in the now available mFISH probe sets, as those do not normally cover the acrocentric short arms; the large pericentric regions of chromosomes 1, 9, and 16; as well as the band Yq12. Still, these regions can be involved in different kinds of chromosomal rearrangements such as translocations, insertions, inversions, amplifications, and marker chromosome formations. Here, examples are given for all these kinds of chromosomal aberrations, detected as constitutional rearrangements in clinical cases. Application perspectives of the probe set in tumors as well as in evolutionary cytogenetic studies are given.

Polymorphic markers suggest a gene flow of CFTR gene from Sub-Saharan/Arabian and Mediterranean to Brazilian Population.

The analysis of 2 diallelic loci (M470V and T854T) and a microsatellite IVS8(T)n of the cystic fibrosis transmembrane conductance regulator (CFTR) gene has shown different haplotype distribution in Brazilian cystic fibrosis (CF) chromosomes carrying different CF mutations. The DeltaF508 mutation was in absolute linkage disequilibrium with 1-1 haplotype (M470V-T854T). Most of DeltaF508 chromosomes (84%) were found to carry the IVS8-9T. The most frequent haplotypes IVS8-7T and 2-1 (M470V-T854T) were found associated with Non-DeltaF508 mutations. Although there is a remarkable linkage disequilibrium between these markers with CFTR locus, the mutations R334W (7T-1-2 and 7T-2-1) and the 3120 + 1G --> A (7T-1-2 and 9T-1-2) are associated with two different haplotypes probably introduced in the Brazilian population by migration. These findings suggest that recombination events from the original haplotype and gene flow among different ethnic groups (sub-Saharan and Mediterranean) might have resulted in CF mutations associated with different haplotypes by independent introductions.

Apoptosis and expression of anti- and pro-apoptotic proteins in peripheral blood mononuclear cells of Fanconi anaemia patients: a study of 73 cases.

Fanconi anaemia (FA) is a rare genetic disease whose patients have a high predisposition to haematological abnormalities and cancer. Fas expression levels in peripheral blood lymphocytes samples of 73 FA patients were measured to verify if alterations in Fas expression could lead to predisposition/resistance to spontaneous or PHA induced apoptosis, as well as, to reflect some haematological features of this disease. The anti- and pro-apoptotic proteins Bcl-2 and Bax were also evaluated. FA patients samples could be divided into three different groups based on Fas expression: 20 samples had low, 32 normal and 21 increased Fas levels when compared to 41 control samples. No correlation was found between Fas and Bcl-2 expression but a good association was obtained with Bax, in the subgroup with increased Fas expression. The best correlation was seen between Bax expression and apoptosis. Out of the 15 samples with high Bax expression, 11 underwent apoptosis whereas only one out of seven samples with low levels of Bax displayed increased induced apoptosis. Most patients with normal haematological features expressed Fas within normal levels. It is difficult to establish, however, if Fas-expression is involved in the cause or is a consequence of the effects observed.

Molecular analysis of 23 exons of the CFTR gene in Brazilian patients leads to the finding of rare cystic fibrosis mutations.

To define mutations present in 23 exons and flanking intronic sequences of the cystic fibrosis transmembrane conductance regulator (CFTR) gene in 95 patients from Rio de Janeiro, Brazil, we carried out single-strand conformation polymorphism analysis and automated direct sequencing. Mutation detection was achieved in 45% of the alleles presented, and complete genotyping (two mutated alleles) was accomplished in 34.7% of the patients. Twenty patients (21.1%) were found to carry only one mutation, whereas mutated alleles could not be observed in 42 patients (44.2%). Eleven mutations were found, of which four were characterized as rare mutations: P205S (1.05%), Y1092X (0.53%), S549R (0.53%), and S4X (0.53%). The DF508 mutation in this population sample showed a frequency of 28.42%. The low number of individuals (10 of 95; 10.5%) with compound heterozygous (DF508/non-DF508) genotypes could indicate the presence of another severe mutation leading to the premature death of these individuals. In 4 of the aforementioned 10 individuals with compound heterozygous genotypes, the D-7-2-1-2 (XV2c-KM19-IVS6a-TUB9-M470-T854) haplotype was defined.

Haplotype distribution of and linkage disequilibrium between four polymorphic markers near the CFTR locus in Brazilian cystic fibrosis patients.

To contribute to a better understanding of the origin and distribution of CFTR mutations in the Brazilian population, we have investigated the linkage between four polymorphic markers (XV2c, KM19, GATT, and TUB9) within or near the CFTR locus. The distribution of alleles for each polymorphism for both parental and cystic fibrosis (CF) chromosomes from Rio de Janeiro CF families were ascertained using a maximum-likelihood method. This same method was applied to study the distribution of the haplotypes defined by these markers. There was no significant association between the XV2c and KM19 loci on the parental and CF chromosomes. On the other hand, a strong association between GATT and TUB9 loci was observed on both CF and parental chromosomes, and striking linkage disequilibrium between the GATT-TUB9 pair and deltaF508 was observed (chi2 = 26.48, p < 0.0001). Remarkable linkage disequilibrium between the GATT-TUB9 marker pair and non-deltaF508 was also found (chi2 = 17.05, p < 0.0001). Our finding of a linkage disequilibrium between GATT-TUB9 and the CFTR locus could suggest that gene flow between different ethnic groups, mainly sub-Saharan and Mediterranean populations, with Brazilian populations could have resulted in some CF mutations originating on chromosomes that carried the GATT-TUB9 marker haplotype 7-2 (OR = 1.34 < 2.83 < 6.00; p = 0.0066).

Association of Turner's syndrome and hypopituitarism: a patient report.

Turner's syndrome (TS) is associated with a wide spectrum of clinical features, such as short stature and gonadal dysgenesis. While it is a common chromosomal abnormality, the association of Turner's syndrome and hypopituitarism is an uncommon finding. We describe here a girl with concomitant pituitary insufficiency and gonadal dysgenesis. When she was 7 years old, her mother reported that she suffered from frontal headache, asthenia and delayed growth. Basal laboratory thyroid evaluation suggested hypothyroidism, with no evidence of autoimmune disease association. She began taking L-thyroxine. At age 11 years, short stature and complaints of frontal headache still persisted. She was still prepubertal and her bone age was delayed by 2.2 years. Her karyotype was compatible with 45,X/46,XX (100 cells analyzed by FISH) and a CT scan showed empty sella. At 12 years of age, an anterior pituitary stimulation test with insulin, gonadotropin-releasing hormone (GnRH) and thyrotropin-releasing hormone (TRH) showed gonadotropin, thyrotropin (TSH) and growth hormone (GH) deficiency. Replacement therapy with GH was begun and she grew 12 cm during the first year of treatment. This report illustrates that, despite the high incidence of sinusitis, short stature and primary hypothyroidism in TS, we should consider the presence of hypopituitarism when the patient presents low levels of TSH with negative thyroid antibodies and inappropriately low levels of gonadotropins for patients with gonadal dysgenesis.