Multiple TP53 p.R337H haplotypes and implications for tumor susceptibility.

The germline TP53 p.R337H mutation is reported as the most common germline TP53 variant. It exists at a remarkably high frequency in the population of southeast Brazil as founder mutation in two distinct haplotypes with the most frequent co-segregating with the p.E134∗ variant of the XAF1 tumor suppressor and an increased cancer risk. Founder mutations demonstrate linkage disequilibrium with neighboring genetic polymorphic markers that can be used to identify the founder variant in different geographic regions and diverse populations. We report here a shared haplotype among Brazilian, Portuguese, and Spanish families and the existence of three additional distinct TP53 p.R337H alleles. Mitochondrial DNA sequencing and Y-STR profiling of Brazilian carriers of the founder TP53 p.R337H allele reveal an excess of Native American haplogroups in maternal lineages and exclusively European haplogroups in paternal lineages, consistent with communities established through male European settlers with extensive intermarriage with Indigenous women. The identification of founder and independent TP53 p.R337H alleles underlines the importance for considering the haplotype as a functional unit and the additive effects of constitutive polymorphisms and associated variants in modifier genes that can influence the cancer phenotype.

Casework direct kit as an alternative extraction method to enhance touch DNA samples analysis.

Latent fingerprints are commonly found in crime scenes, and currently used in forensic analysis to obtain STR profiles from DNA recovered from finger contact. Analysis of STR profiles obtained from touch DNA has been very useful to elucidate crimes and the extraction method may be determinant for the recovery of genetic material collected from different surfaces. This study aimed to verify and compare the efficiency of two different extraction kits for processing touch DNA samples obtained from fingerprints deposited on computer keyboards, knife handles and exterior door handles and steering wheels of cars. One hundred and four experiments were conducted to simulate crime scenes and evaluate the efficiency of two extraction kits for touch DNA samples: the DNA IQ™ System and the Casework Direct Kit (both Promega Corporation). Each experiment was conducted with two individuals in order to obtain a mixture profile. The genetic material deposited was collected by double swab method (Sweet et al. 1997) and DNA quantification was conducted using Quantifiler Trio™ (ThermoFisher Scientific). Samples were amplified by PowerPlex® Fusion System kit (Promega). It was possible to obtain STR profiles for 32 (61.5%) out of the 52 extracted using DNA IQ and 51 (98.1%) out of the 52 extracted using the Casework Direct Kit. Samples extracted by DNA IQ had higher average of quantification values for long targets (>200bp) across all tested surfaces. That seems to be due to an incompatibility between the Quantifiler Trio and the Casework Direct Kit. Samples with positive quantification but without STR profile, as well as samples without quantification but with STR profiles were also observed. Statistical analysis showed that the Casework Direct Kit produced significantly more useful profiles than DNA IQ (p-value = 0.001), since these profiles had more STR markers with allelic correspondence to second donators present in the mixture. This study provides insights about the effect of different surfaces and extraction methods on recovery and generation of STR profiles. Limitations for the quantification step for these samples with a low quantity of DNA were highlighted as well. We concluded that the Casework Direct Kit was much more efficient for processing touch DNA samples than DNA IQ.

Male lineages in Brazilian populations and performance of haplogroup prediction tools.

The use of Y-chromosomal genetic markers in forensic investigations demands the establishment of reliable and representative DNA databases of different reference populations. The genetic characterization of the Y chromosome variation in human populations requires the analyses of haplotype frequencies allied to haplogroup determination. The present study aimed to contribute to the Brazilian database by providing 1,382 Yfiler Plus individual profiles, from 11 Brazilian states. The Yfiler Plus markers showed high haplotype diversities in all Brazilian populations (>0.9970), allowing high intra-population discrimination in forensic investigations. Pairwise genetic distances showed a homogeneity between Brazilian populations (FST ≤ 0.0043; non-differentiation p-values ≥ 0.0212), indicating that admixed populations from Brazil can be represented in a single Yfiler Plus haplotype database, for forensic purposes. The performance of Haplogroup Predictor and NevGen software in haplogroup prediction based on Yfiler Plus and Yfiler haplotypes was evaluated in a subset of 416 Brazilian samples that were also genotyped for 51 Y-SNPs. In 25% of the samples, no classification or errors were found for at least one of the prediction tools or marker sets. NevGen presented lower error rates (5.52% and 8.65% with Yfiler Plus and Yfiler, respectively) than Haplogroup Predictor (16.11% with Yfiler Plus and 13.70% with Yfiler). In conclusion, both haplogroup prediction tools can be useful to direct the SNP typing, but present large error rates to be used in forensic analysis, especially in predicting African haplogroups in admixed South American populations.

Polymorphisms of mitochondrial DNA control region are associated to endometriosis.

PURPOSE: Polymorphisms in the control region of mitochondrial DNA (mtDNA) can affect generation of reactive oxygen species and impact in the pathogenesis of endometriosis. This study investigated the association of mtDNA polymorphisms with endometriosis. METHODS: Patients were divided in two groups: endometriosis (n = 90) and control (n = 92). Inclusion criteria were as follows: women between 18 and 50 years, with histological diagnosis and surgical staging of endometriosis (endometriosis group) or undergoing gynecological surgery for tubal ligation, leiomyoma, or ovarian cysts, with no evidence of endometriosis (control group). DNA extraction was performed from peripheral blood. Sanger sequencing of mtDNA control region was performed, and polymorphisms were determined comparing the sequences obtained with the Cambridge Reference Sequence. RESULTS: The frequency of polymorphisms T16217C (14.4 and 5.4% of endometriosis and control group, respectively; p = 0.049) and G499A (13.3 vs. 4.3%; p = 0.038) was higher in the endometriosis group, while T146C (32.6 vs. 18.9%; p = 0.042) and 573.2C (5.6 vs. 29.3%; p < 0.001) were lower. No difference was observed in haplogroups between groups. CONCLUSION: mtDNA polymorphisms T16217C and G499A were associated with endometriosis, while T416C and 573.2C were shown to be associated with an absence of disease.

Growth hormone insensitivity with immune dysfunction caused by a STAT5B mutation in the south of Brazil: evidence for a founder effect.

Homozygous STAT5B mutations causing growth hormone insensitivity with immune dysfunction were described in 10 patients since 2003, including two Brazilian brothers from the south of Brazil. Our objectives were to evaluate the prevalence of their STAT5B mutation in this region and to analyze the presence of a founder effect. We obtained DNA samples from 1,205 local inhabitants, 48 relatives of the homozygous patients and four individuals of another affected family. Genotyping for STAT5B c.424_427del mutation and for two polymorphic markers around it was done through fragment analysis technique. We also determined Y-chromosome and mtDNA haplotypes and genomic ancestry in heterozygous carriers. We identified seven families with STAT5B c.424_427del mutation, with 33 heterozygous individuals. The minor allelic frequency of this mutation was 0.29% in this population (confidence interval 95% 0.08-0.5%), which is significantly higher than the frequency of other pathogenic STAT5B allele variants observed in public databases (p < 0.001). All heterozygous carriers had the same haplotype present in the homozygous patients, found in only 9.4% of non-carriers (p < 0.001), supporting the existence of a founder effect. The Y-chromosome haplotype, mtDNA and genomic ancestry analysis indicated a European origin of this mutation. Our results provide compelling evidence for a founder effect of STAT5B c.424_427del mutation.

Growth hormone insensitivity with immune dysfunction caused by a STAT5B mutation in the south of Brazil: evidence for a founder effect

ABSTRACT Homozygous STAT5B mutations causing growth hormone insensitivity with immune dysfunction were described in 10 patients since 2003, including two Brazilian brothers from the south of Brazil. Our objectives were to evaluate the prevalence of their STAT5B mutation in this region and to analyze the presence of a founder effect. We obtained DNA samples from 1,205 local inhabitants, 48 relatives of the homozygous patients and four individuals of another affected family. Genotyping for STAT5B c.424_427del mutation and for two polymorphic markers around it was done through fragment analysis technique. We also determined Y-chromosome and mtDNA haplotypes and genomic ancestry in heterozygous carriers. We identified seven families with STAT5B c.424_427del mutation, with 33 heterozygous individuals. The minor allelic frequency of this mutation was 0.29% in this population (confidence interval 95% 0.08-0.5%), which is significantly higher than the frequency of other pathogenic STAT5B allele variants observed in public databases (p < 0.001). All heterozygous carriers had the same haplotype present in the homozygous patients, found in only 9.4% of non-carriers (p < 0.001), supporting the existence of a founder effect. The Y-chromosome haplotype, mtDNA and genomic ancestry analysis indicated a European origin of this mutation. Our results provide compelling evidence for a founder effect of STAT5B c.424_427del mutation.

CCDC22 gene polymorphism is associated with advanced stages of endometriosis in a sample of Brazilian women.

PURPOSE: Based on the assumption that genetic factors are involved in the etiology of endometriosis, this study aimed to investigate the possibility of rs498679 (TLR4 gene), rs1799964 (TNF-α gene), rs3024496 (IL-10 gene), and rs2294021 (CCDC22 gene) polymorphisms being associated with the occurrence of this disease in a sample of Brazilian women. METHODS: We conducted a case-control study with 100 women with histological confirmation of endometriosis (endometriosis group) and 100 women submitted to laparoscopy for benign disorders, in which the absence of endometriosis was confirmed (control group). All samples were genotyped by real-time PCR technique for rs498679, rs1799964, rs3024496, and rs2294021 polymorphisms. RESULTS: No significant difference was observed in genotypic or allelic frequencies between control and endometriosis groups for rs498679 (TLR4 gene), rs1799964 (TNF-α gene), rs3024496 (IL-10 gene), neither when comparing endometriosis subgroups (I-II versus III-IV). On the other hand, significant difference between stages I-II and III-IV of the disease was found in genotypic and allelic frequencies for the rs2294021 (CCDC22 gene) SNP (p = 0.048 and p = 0.017, respectively). CONCLUSION: Our results suggest that the rs2294021 (CCDC22 gene) polymorphism could be associated with increased susceptibility to endometriosis in Brazilian women when the allele C is present. In order to clarify this result, further studies should be conducted on a larger population.

Polymorphisms of ICAM-1 and IL-6 genes related to endometriosis in a sample of Brazilian women.

PURPOSE: This study investigated the possibility of K469E (rs5498) and G241R (rs1799969) polymorphisms, in ICAM-1 gene, and G634C (rs1800796), in IL-6 gene, being associated with the occurrence of endometriosis in a sample of Brazilian women. METHODS: We genotyped 200 women (100 in control group and 100 in endometriosis group) by PCR-RFLP technique for G634C, K469E, and G241R polymorphisms. RESULTS: No significant difference was observed in genotypic frequency between control and endometriosis groups for G634C and K469E polymorphisms (p = 0.61 and p = 0.22, respectively). In addition, no significant difference between stages I-II and III-IV of the disease was found for both SNPs (p = 0.63 and p = 0.24, respectively). All individuals were wild homozygotes for G241R polymorphism. CONCLUSION: This study suggests that polymorphisms K469E, G241R, and G634C are not associated with increased susceptibility to endometriosis in Brazilian women.

Post-mortem cytogenomic investigations in patients with congenital malformations.

Congenital anomalies are the second highest cause of infant deaths, and, in most cases, diagnosis is a challenge. In this study, we characterize patterns of DNA copy number aberrations in different samples of post-mortem tissues from patients with congenital malformations. Twenty-eight patients undergoing autopsy were cytogenomically evaluated using several methods, specifically, Multiplex Ligation-dependent Probe Amplification (MLPA), microsatellite marker analysis with a MiniFiler kit, FISH, a cytogenomic array technique and bidirectional Sanger sequencing, which were performed on samples of different tissues (brain, heart, liver, skin and diaphragm) preserved in RNAlater, in formaldehyde or by paraffin-embedding. The results identified 13 patients with pathogenic copy number variations (CNVs). Of these, eight presented aneuploidies involving chromosomes 13, 18, 21, X and Y (two presented inter- and intra-tissue mosaicism). In addition, other abnormalities were found, including duplication of the TYMS gene (18p11.32); deletion of the CHL1 gene (3p26.3); deletion of the HIC1 gene (17p13.3); and deletion of the TOM1L2 gene (17p11.2). One patient had a pathogenic missense mutation of g.8535C>G (c.746C>G) in exon 7 of the FGFR3 gene consistent with Thanatophoric Dysplasia type I. Cytogenomic techniques were reliable for the analysis of autopsy material and allowed the identification of inter- and intra-tissue mosaicism and a better understanding of the pathogenesis of congenital malformations.

SLC24A5 and ASIP as phenotypic predictors in Brazilian population for forensic purposes.

Pigmentation is a variable and complex trait in humans and it is determined by the interaction of environmental factors, age, disease, hormones, exposure to ultraviolet radiation and genetic factors, including pigmentation genes. Many polymorphisms of these genes have been associated with phenotypic diversity of skin, eyes and hair color in homogeneous populations. Phenotype prediction from biological samples using genetic information has benefited forensic area in some countries, leading some criminal investigations. Herein, we evaluated the association between polymorphisms in the genes SLC24A5 (rs1426654) and ASIP (rs6058017) with skin, eyes and hair colors, in 483 healthy individuals from Brazilian population for attainable use in forensic practice. The volunteers answered a questionnaire where they self-reported their skin, eye and hair colors. The polymorphic homozygous genotype of rs1426654∗A and rs6058017∗A in SLC24A5 and ASIP respectively, showed strongest association with fairer skin (OR 47.8; CI 14.1-161.6 and OR 8.6; CI 2.5-29.8); SLC24A5 alone showed associations with blue eyes (OR 20.7; CI 1.2-346.3) and blond hair (OR 26.6; CI 1.5-460.9). Our data showed that polymorphic genotypes (AA), in both genes, are correlated with characteristics of light pigmentation, while the ancestral genotype (GG) is related to darker traits, corroborating with previous studies in European and African populations. These associations show that specific molecular information of an individual may be useful to access some phenotypic features in an attempt to help forensic investigations, not only on crime scene samples but also in cases of face reconstructions in unknown bodies.

MYH9 and APOL1 gene polymorphisms and the risk of CKD in patients with lupus nephritis from an admixture population.

MYH9 polymorphisms have been described to be associated with the risk of CKD in non-diabetic nephropathy, HIV nephropathy and FSGS. Predominating in black descendants, MHY9 genetic variants could partially explain the excess risk of CKD associated with African ancestry. However, recent data suggests that APOL1 gene co-segregate with MYH9, and could be the gene truly associated with CKD risk. In this study, we evaluated the role of MYH9 and APOL1 gene polymorphisms in the risk of CKD in Brazilian patients with lupus nephritis (LN). A retrospective analysis of 196 LN patients was done. MYH9 rs4821480, rs2032487, rs4821481 and rs3752462, APOL 1rs73885319, rs16996616, rs60910145, rs71785313, and APOL3 rs11089781 gene polymorphisms were determined. Genetic ancestry was ascertained both by autossomal ancestry and mitochondrial haplogroup. Primary outcome was defined as doubling of serum creatinine (DC) or end stage renal disease (ESRD). Sixty-two patients presented the PO. In our population, MYH9 and APOL1 were not in LD. None APOL polymorphism was associated with the PO, whereas rs3752462 MYH9 polymorphism showed a positive association (HR3.72, 95%CI 1.47-9.38, p = 0.005). When we analyzed the MYH9 E1 haplotype, the GCCT carriers (1 or 2 alelles present in 29.7% in the PO group vs. 18.5% in controls) showed a significant association to the risk of PO, even after adjustments for baseline estimated creatinine clearance and autossomal ancestry (HR 2.0, 95%CI 1.2-3.4, p = 0.01). Our results show that in our population MYH9, but not APOL1, gene polymorphisms confer an increased risk of CKD in LN patients, independently of race.

The E180splice mutation in the GHR gene causing Laron syndrome: witness of a Sephardic Jewish exodus from the Iberian Peninsula to the New World?

Laron syndrome (LS) is a genetic disorder caused by mutations in the growth hormone receptor (GHR) gene. The most frequent GHR mutation is E180splice (rs121909360), which was initially found in an inbred population of Spanish descent in Ecuador and subsequently in Israel, Brazil, Chile, and the United States. The aim of the present study is to determine if the E180splice mutation arose from a common origin. We studied 22 patients with LS from Ecuador, Israel (of Moroccan origin), Brazil, Chile, and the United States (of Mexican origin) who were homozygous for the E180splice mutation and compared them to control individuals for markers surrounding the GHR, intragenic polymorphisms, and Y-chromosome STR. An identical haplotype was found in all but one of the subjects carrying the E180splice mutation: D5S665: 150/150; D5S2082: 192/192; D5S2087: 246/246; rs6179 G/G; and rs6180 C/C. One patient differed from the others only at D5S2082 (168/192). This haplotype is rare (~1%) in control individuals and confirmed that the E180splice-associated haplotype was not derived from independent origins but represented recombination from a common ancestor. The analysis of paternal lineage markers showed that 50% belong to haplogroup R1b (found in Portugal and Spain) and 40% to haplogroups J and E (typical in the Middle East and in Eastern European Jews). The germline E180Splice mutation appears to have originated from a single common ancestor. The presence of Y-chromosome markers associated with Sephardic populations in persons harboring the E180splice mutation provides genetic evidence in support of the historical tracking of the exodus of this specific population.

Assessment of the relationship between self-declared ethnicity, mitochondrial haplogroups and genomic ancestry in Brazilian individuals.

In populations that have a high degree of admixture, such as in Brazil, the sole use of ethnicity self-declaration information is not a good method for classifying individuals regarding their ethnicity. Here, we evaluate the relationship of self-declared ethnicities with genomic ancestry and mitochondrial haplogroups in 492 individuals from southeastern Brazil. Mitochondrial haplogroups were obtained by analyzing the hypervariable regions of the mitochondrial DNA (mtDNA), and the genomic ancestry was obtained using 48 autosomal insertion-deletion ancestry informative markers (AIM). Of the 492 individuals, 74.6% self-declared as White, 13.8% as Brown and 10.4% as Black. Classification of the mtDNA haplogroups showed that 46.3% had African mtDNA, and the genomic ancestry analysis showed that the main contribution was European (57.4%). When we looked at the distribution of mtDNA and genomic ancestry according to the self-declared ethnicities from 367 individuals who self-declared as White, 37.6% showed African mtDNA, and they had a high contribution of European genomic ancestry (63.3%) but also a significant contribution of African ancestry (22.2%). Of the 68 individuals who self-declared as Brown, 25% showed Amerindian mtDNA and similar contribution of European and African genomic ancestries. Of the 51 subjects who self-declared as black, 80.4% had African mtDNA, and the main contribution of genomic ancestry was African (55.6%), but they also had a significant proportion of European ancestry (32.1%). The Brazilian population had a uniform degree of Amerindian genomic ancestry, and it was only with the use of genetic markers (autosomal or mitochondrial) that we were able to capture Amerindian ancestry information. Additionally, it was possible to observe a high degree of heterogeneity in the ancestry for both types of genetic markers, which shows the high genetic admixture that is present in the Brazilian population. We suggest that in epidemiological studies, the use of these methods could provide complementary information.

A new duplication in the mitochondrially encoded tRNA proline gene in a patient with dilated cardiomyopathy.

Mitochondria provide an environment conducive to mutations in DNA molecules (mtDNA). Analyses of mtDNA have shown mutations potentially leading to many cardiovascular traits. Here, we describe a patient with dilated cardiomyopathy and new mtDNA duplication. The patient presented symptoms of heart failure New York Heart Association functional class III and was diagnosed with non-familial dilated cardiomyopathy with important left ventricular systolic dysfunction. Sequencing of mtDNA control region was done, and a 15 bp duplication was observed between nucleotides 16,018 and 16,032. Part of this duplication is localized within the tRNA proline gene (tRNA(Pro)) that has an important role in cell protection against oxidative stress and is considered an important regulatory factor for cellular reactive oxygen species balance. This duplication could alter the stability or secondary structure of tRNA(Pro), affecting mt-protein synthesis. In turn, the presence of duplication in tRNA(Pro) could cause some oxidative stress imbalance and, so, mitochondrial dysfunction could result in the pathogenicity.

Establishment and characterization of human bladder cancer cell lines BexBra1, BexBra2, and BexBra4.

Bladder cancer (BC) is the fourth most common cancer in the USA. In Brazil, BC represents 3% of the total existing carcinomas in the population and represents the second highest incidence among urological tumors. The majority of bladder cancer cell lines available were derived from Caucasians and established in the seventies or eighties. Thus, neoplasia development in these cells likely occurred in environment conditions vastly different than today. In the present study, we report the establishment and characterization of three Brazilian bladder cancer cell lines (BexBra1, BexBra2, and BexBra4). These cell lines may be helpful for dissecting the genetic and epigenetic aspects that trigger the progression of BC. Moreover, the development of a Brazilian representative of the disease will allow us to investigate the potential inter-racial differences of malignancy-associated phenotypes in bladder cancer.

Establishment and characterization of androgen-independent human prostate cancer cell lines, PcBra1, PcBra2, and PcBra3.

One of the main obstacles for understanding biological events involved in cancer is the lack of experimental models for in vitro studies especially for prostate cancer (PC). There are a limited number of PC cell lines being the majority originated from metastatic tumors mostly acquired from American Tissue Cell Culture which demands importation an expensive and bureaucratic process. Also it is well known that there are ethnic differences between populations concerning the behavior of tumors and the research based on cell lines derived from Brazilians should be interesting. Our aim was to develop tumor cell lines from primary PC.

Brazilian population profile of 15 STR markers.

Allele frequencies for 15 STR markers included in the AmpFISTR Identifiler kit (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, and FGA) were obtained from a sample of 561 unrelated individuals from São Paulo, Brazil.

Inv dup (15): is the electroclinical phenotype helpful for this challenging clinical diagnosis?

OBJECTIVE: To study the electroclinical phenotype in 5 patients with large supernumerary marker chromosome referred as inv dup (15), in an attempt to analyze the electroclinical spectrum in order to determine if the binomial epilepsy-EEG is stereotyped enough to corroborate this challenging diagnosis. METHODS: Five patients with large inv dup (15) were submitted to EEG and/or V-EEG, with a minimum duration of 2h. Two certified neurophysiologists analyzed all EEG tracings simultaneously, blinded to clinical and molecular data. Epilepsy was characterized by detailed history and a standard questionnaire according to International League Against Epilepsy guidelines and corroborated by V-EEG findings. RESULTS: Epilepsy started during infancy in 4 patients, in 3 with spasms. Spasms were easily controlled in one but not in others. Epilepsy evolved with generalized seizures in two patients and, generalized and focal in one. Currently, 3 patients present refractory epilepsy and two are seizure-free. In one patient, only one isolated episode suggestive of a secondary generalized tonic-clonic event occurred at the age of 12 years without recurrence. Regarding the EEG, patients had distinct features, except for two patients with very high amplitude fast activity, resembling recruiting rhythm. Despite good seizure outcome in 3 patients, EEGs remained remarkably abnormal with frequent epileptiform discharges over poorly organized background. CONCLUSIONS: Our data showed a heterogeneous electroclinical phenotype with generalized and partial epilepsy, presenting distinct degrees of severity and refractoriness. SIGNIFICANCE: Our findings suggest that it is not possible to delineate an electroclinical phenotype in this neurogenetic syndrome. Therefore, inv dup (15) remains as a diagnostic challenge and epilepsy and EEG features are valuable only when inserted in the proper clinical context.

Epilepsy in patients with angelman syndrome caused by deletion of the chromosome 15q11-13.

BACKGROUND: Angelman syndrome (AS) is a neurogenetic disorder characterized by severe mental retardation, speech disorder, stereotyped jerky movements, and a peculiar behavioral profile, with a happy disposition and outbursts of laughter. Most patients with AS present with epilepsy and suggestive electroencephalographic patterns, which may be used as diagnostic criteria. OBJECTIVE: To study epilepsy and response to treatment in a series of patients with AS determined by deletion. DESIGN: Parent and caregiver interview and medical record review. SETTING: Epilepsy Center at the University of São Paulo. PATIENTS: Nineteen patients with AS determined by deletion of chromosome 15q11-13. MAIN OUTCOME MEASURES: Epilepsy severity, epilepsy evolution, and response to antiepileptic drug treatment. RESULTS: All patients with AS in this group had generalized epilepsy, and 10 (53%) also had partial epilepsy. Main seizure types were atypical absences and myoclonic and tonic-clonic seizures. Mean age at onset was 1 year 1 month. Epilepsy aggravated by fever occurred in 10 patients (53%) and status epilepticus in 16 (84%). Eighteen patients (95%) had previous or current history of daily seizures, of which 14 (64%) had disabling seizures. Multiple seizure types were observed in 13 patients (53%). History of refractory epilepsy was reported in 16 patients (84%). Parents reported improvement, characterized by decrease in seizure frequency or seizure control, at the mean age of 5.3 years. Therefore, most of these patients had a period of refractory epilepsy; however, improvement occurred during late childhood and puberty. The best therapeutic response was obtained with valproic acid alone or in association with phenobarbital or clonazepam. Epilepsy was aggravated by carbamazepine, oxcarbazepine, and vigabatrin. CONCLUSIONS: Patients with AS with deletion have epilepsy with early onset and stereotyped electroclinical profile regarding seizure type, severity, and response to antiepileptic drug treatment. Another feature of AS is the age-related improvement, even in refractory cases, during late childhood and puberty. These characteristics are not specific to this syndrome but, when inserted in the proper clinical context, may anticipate diagnosis. We believe that AS should be considered a differential diagnosis in developmentally delayed infants with severe, generalized, cryptogenic epilepsy; however, a proper electroclinical delineation of each genetic group is mandatory.