Luiz Alkimin de Lacerda

Penetrance of adrenocortical tumours associated with the germline TP53 R337H mutation

Background: An inherited germline P53 mutation has been identified in cases of childhood adrenocortical carcinoma (ACT), a neoplasm with a high incidence in southern Brazil. The penetrance of ACT in carriers of the point mutation, which encodes an arginine-to-histidine substitution at codon 337 of TP53 (R337H), has not been determined. Objective: To investigate the penetrance of childhood ACT in carriers of the R337H TP53 mutation. Methods: The family histories of 30 kindreds of 41 southern Brazilian children with ACT were obtained. A PCR based assay was used to detect this P53 mutation in a large number of relatives of children with ACT. In all, 927 individuals were tested for the mutation, 232 from the non-carrier and 695 (including the 40 probands) from the carrier parental lines. Results: 40 children with ACT carried the TP53 R337H mutation; the remaining child with ACT was not tested. There was no evidence of Li-Fraumeni syndrome in any of the kindreds; however, seven met the criteria for Li-Fraumeni-like syndrome. The carrier parental line was identified in each kindred. Of the 695 individuals tested in the carrier parental line, 240 (34.5%) were positive for the mutation, while none of the 232 individuals in the other parental line carried the mutation. The penetrance of ACT was 9.9% (95% confidence interval, 8.7% to 11.1%). Conclusions: The TP53 R337H mutation dramatically increases predisposition to childhood ACT but not to other cancers, and explains the increased frequency of ACT observed in this geographic region.

Clinical characteristics of small functioning adrenocortical tumors in children

Twenty of 67 children registered on the International Registry of Childhood Adrenocortical Tumors between May 1988 and December 1994 had small adrenocortical tumors (defined for this study as measuring < or = 200 cm3 and/or weighing < or = 100 g). We reviewed the records of these 20 patients to characterize the clinical and pathologic findings and outcomes of children with small adrenocortical tumors. Median patient age was 2 years (range, 4 months to 5 years). There was only one boy. All had clinical signs of virilization, and seven had signs or symptoms of Cushing syndrome. A median 5.5 months (range, 1-40 months) had elapsed between the first signs of endocrine dysfunction and diagnosis. All tumors were surgically resected. Tumor volume was 3.3-195 cm3 (median, -8.7 cm3), and weight was 3.7-100 g (median, 36 gm Tumor samples were histologically reviewed in 18 cases. Eight were adenomas, and 10 were carcinomas (6 low grade and 4 high grade). Pathology records described tumor with diagnostic features of adrenocortical carcinoma in two patients. One patient received mitotane for 8 months after surgery. Only one patient had recurrent disease, which was detected 6 months after diagnosis and proved rapidly fatal. Another has been lost to follow-up. The remaining 18 patients are alive with no evidence of disease at a median 2.3 years (range, 6 months to 6.1 years) after diagnosis. Our data suggest that children with small adrenocortical tumors have an excellent prognosis with surgery as the sole therapy, regardless of tumor histiotype.

In vitro and in vivo responses to short-term recombinant human insulin-like growth factor-1 (IGF-I) in a severely growth-retarded girl with ring chromosome 15 and deletion of a single allele for the type 1 IGF receptor gene

Patients with single allele defects in the gene encoding the type 1 IGF receptor have been reported to have growth failure, but fibroblasts from affected patients have not exhibited insensitivity to the effects of IGF‐I in vitro. The in vitro and in vivo responses to short‐term recombinant human IGF‐I (rhIGF‐I) in a severely growth‐retarded girl with ring chromosome 15 and deletion of a single allele for the type 1 IGF receptor gene have been investigated.

Clinical and Molecular Analysis of Thyroid Hypoplasia: A Population-Based Approach in Southern Brazil

BACKGROUND Congenital hypothyroidism (CH) is mainly due to developmental abnormalities leading to thyroid dysgenesis (TD). TD encompasses very distinct morphologic subtypes of disease. This study examined and compared the phenotype in TD variants and searched for genetic alterations in sporadic thyroid hypoplasia (TH), the most misdiagnosed form of CH. This was a longitudinal study over a 14-year period (1990-2004). METHODS A continuous series of 353 children with TD was identified using thyroid function tests [thyroxine (T4) and TSH], scintigraphy, and ultrasound as diagnostic tools. Individual phenotypes were analyzed in 253 children with TD. Mutations in the most likely candidate genes were studied in 35 cases of TH. RESULTS The overall birth prevalence of permanent CH was 1:4795. Ectopy represented 37% of all cases of permanent primary CH, dyshormonogenesis 28%, agenesis 24%, hypoplasia 10%, and hemiagenesis 1%. The lowest screening T4 level and the highest TSH level were in the agenetic group, followed by TH. The TH group had an improvement in the thyroid function showing less-severe phenotype with aging. In the molecular analysis, one patient was identified with a mutation in the PAX8 gene (155G>C; R52P); four patients had a heterozygous G>C substitution in position -569; two patients showed a (234C>A; P52T) or (2181C>G; D727E) polymorphic variants of the TSH-R gene; and one patient presented a novel heterozygous nonsynonymous substitution, 293G>A; S98N, in the NKX2.5 gene. CONCLUSIONS The prevalence of CH was within the previously reported range of 1:3000-4000. Ectopy was the most common etiology. Clinical analysis revealed distinct hormonal patterns in TH subgroup when compared with other variants of TD, with genetic abnormalities identified only in few cases in the TSH-R, PAX8, and NKX2.5 genes.

Molecular analyses of the vasopressin type 2 receptor and aquaporin‐2 genes in Brazilian kindreds with nephrogenic diabetes insipidus

Nephrogenic diabetes insipidus (NDI) is associated with germline mutations in two genes: vasopressin receptor type 2 (V2(R)) in X‐linked NDI, and the water channel aquaporin‐2, in autosomal‐recessive disease. Genetic heterogeneity is further emphasized by reports of phenotypically abnormal individuals with normal structural genes. We analyzed both genes in five Brazilian families and the aquaporin‐2 gene in two Swedish families with clinical and laboratory diagnosis of NDI, by a combination of denaturing gradient gel electrophoresis (DGGE) and direct DNA sequencing. A novel polymorphism in the aquaporin‐2 gene (S167S), but no disease‐associated mutations in any tested individual from all seven families, was detected. In two Brazilian families, frameshift mutations were detected in the V2(R) gene: one leading to a premature stop after codon 36 and the other to a longer peptide (462 aa instead of the 373 aa wild‐type protein). In two other Brazilian families, probable disease‐associated missense mutations were detected: an alanine to proline at codon 163 (A163P) and an asparagine to aspartic acid at codon 85 (D85N). In one Brazilian family, both genes were structurally normal and the aquaporin‐2 gene was also normal in the two Swedish kindreds. This report further extends the mutational spectrum of NDI and suggests that there are other mutational or epigenetic events inactivating the two known genes or even novel genes that underlie NDI. Hum Mutat 14:233–239, 1999.

Muscle strength and body composition during the transition phase in patients treated with recombinant GH to final height

Abstract We assessed body composition and muscle strength during the transition phase in 18 growth hormone (GH) deficient males treated with recombinant GH to final height and 18 controls. According to peak-stimulated GH and basal insulin-like growth factor-1 (IGF-1) during the transition phase, patients were subdivided into GH deficient (GHD-TP, n=9) and GH sufficient (GHS-TP, n=9) groups. Assessments included lean and fat body mass and bone mineral density (BMD), all measured by dual-energy X-ray absorptiometry, and dynamic knee muscle strength, assessed by isokinetic dynamometer. Total body and lumbar spine BMD and muscle strength were lower in GHD-TP patients when compared with GHS-TP and controls (all p<0.05), whereas lean and fat body mass were lower in both GHD-TP and GHS-TP patients when compared with controls (p<0.05). These findings suggest that administration of recombinant GH to final height is not sufficient to provide normal body composition and muscle strength in young male patients with GH deficiency.

An Intron 9 CYP19 Gene Variant (IVS9+5G>A), Present in an Aromatase-Deficient Girl, Affects Normal Splicing and Is Also Present in Normal Human Steroidogenic Tissues.

Background/Aims: Splicing CYP19 gene variants causing aromatase deficiency in 46,XX disorder of sexual development (DSD) patients have been reported in a few cases. A misbalance between normal and aberrant splicing variants was proposed to explain spontaneous pubertal breast development but an incomplete sex maturation progress. The aim of this study was to functionally characterize a novel CYP19A1 intronic homozygote mutation (IVS9+5G>A) in a 46,XX DSD girl presenting spontaneous breast development and primary amenorrhea, and to evaluate similar splicing variant expression in normal steroidogenic tissues. Methods: Genomic DNA analysis, splicing prediction programs, splicing assays, and in vitro protein expression and enzyme activity analyses were carried out. CYP19A1 mRNA expression in human steroidogenic tissues was also studied. Results: A novel IVS9+5G>A homozygote mutation was found. In silico analysis predicts the disappearance of the splicing donor site in intron 9, confirmed by patient peripheral leukocyte cP450arom and in vitro studies. Protein analysis showed a shorter and inactive protein. The intron 9 transcript variant was also found in human steroidogenic tissues. Conclusions: The mutation IVS9+5G>A generates a splicing variant that includes intron 9 which is also present in normal human steroidogenic tissues, suggesting that a misbalance between normal and aberrant splicing variants might occur in target tissues, explaining the clinical phenotype in the affected patient.

Fractal Fracture Mechanics Applied to Materials Engineering

The Classical Fracture Mechanics (CFM) quantifies velocity and energy dissipation of a crack growth in terms of the projected lengths and areas along the growth direction. However, in the fracture phenomenon, as in nature, geometrical forms are normally irregular and not easily characterized with regular forms of Euclidean geometry. As an example of this limitation, there is the problem of stable crack growth, characterized by the J-R curve [1, 2]. The rising of this curve has been analyzed by qualitative arguments [1, 2, 3, 4] but no definite explanation in the realm of EPFM has been provided.

Resistance exercise alone improves muscle strength in growth hormone deficient males in the transition phase.

Abstract Background During the transition phase (TP), patients with growth hormone deficiency (GHD) exhibit decreased muscle strength. Studies assessing the effects of resistance exercise alone on muscle strength in these individuals are scarce. The objective of this study was to evaluate the effects of a program of resistance exercise (PRE) on parameters of muscle strength in subjects in the TP and with childhood-onset GHD treated with recombinant GH (rGH). Methods Sixteen male patients were enrolled and divided into two groups: GHD (n=9) and GH sufficiency (GHS, n=7). Patients with GHD underwent a 12-week PRE followed by another 12-week PRE plus rGH, while GHS patients underwent a 12-week PRE alone. Dynamic knee muscle strength was evaluated using an isokinetic dynamometer. Results Before PRE, there were significant differences between the groups regarding the results of flexor peak torque (FPT) normalized to body weight (BW-FPT) in the dominant (DO, p=0.008) and non-dominant (ND, p=0.01) limbs, and in the agonist/antagonist (A/A) ratio in the DO (p=0.02) and ND (p=0.006) limbs. After PRE in the GHD group, values of FPT and BW-FPT in both limbs increased significantly (p<0.001) and independently of rGH, while the A/A ratio value improved significantly (p<0.001) in the ND limb. Conclusions A short period of PRE alone was sufficient to improve parameters of muscle strength in young male adults with childhood-onset GHD.

Phonological acquisition in children with early-treated congenital hypothyroidism: association with clinical and laboratory parameters

PURPOSE To evaluate the phonological characteristics of children with congenital hypothyroidism (CH). METHODS Observational, analytical, cross-sectional, ambispective study including prepubertal children with CH (n=100; study group, SG) and controls without CH ( n=100; control group, CG). Assessments included a speech language pathology interview, the phonological evaluation of the ABFW Child Language Test, medical data, and neuropsychological tests in the first three years of life. RESULTS On treatment onset of the SG, the median chronological age of the participants was 18.0 days and 48.4% had total T4 <2.5 µg/dL (31.75 nmol/L). At the age of 7 years, children in the SG had higher rates of consonant cluster simplification and lower rates of complete phonological system compared to those in the CG. On analysis of combined age groups (4+5 and 6+7 years), the CG had a higher frequency of complete acquisition versus the SG. On multivariate analysis, thyroid agenesis, abnormal scores on the Clinical Linguistic and Auditory Milestone Scale and developmental quotient tests were associated with the occurrence of phonological disorders. CONCLUSION Children with CH present delay in phonological acquisition, despite early diagnosis and adequate treatment, especially between the ages of 6-7 years. The etiology of CH and the results of neuropsychological tests in the first years of life seem to be related to this delay.