RESUMO
BACKGROUND: LIPA, situated on chromosome 10q23.2-q23.3, encodes the enzyme lysosomal acid lipase (LAL) (EC 3.1.1.13). Genetic alterations in LIPA lead to lysosomal acid lipase deficiency (LALD), an inborn error causing lipid metabolism anomalies and impairing cholesterol and triacylglyceride degradation. Over 40 LIPA variants have been documented, yet this study focuses on just two. The rs1051338 variant (NM_000235:c.46A>C) affects the signal peptide in Exon 2, whereas rs116928232, located in Exon 8, alters the splice site (NM_000235:c.894G>A), impacting lysosomal acid lipase activity. Considering the diverse clinical manifestations of LALD and the rising hepatic steatosis prevalence in Mexican population, mainly due to diet, these variants were investigated within this demographic to uncover potential contributing factors. This study aimed to reveal the frequency of rs1051338 and rs116928232 among healthy mestizo individuals in Northwest Mexico, marking a significant genetic exploration in this demographic. METHODS: Three hundred ten healthy mestizo individuals underwent PCR-RFLP analysis for both variants, and Sanger sequencing was performed for variant rs116928232. Bioinformatic analysis was also performed to predict protein changes. RESULTS: Allele frequencies for rs1051338 (FA = 0.39, p value = 0.15) and rs116928232 (FA = 0.0016, p value = 0.49) aligned with reported data, while bioinformatic analysis allowed us to identify the protein alteration observed in both variants; finally, the variants showed no linkage between them (normalized D' = 1.03, p value = 0.56). CONCLUSIONS: Allelic frequencies closely matched reported data, and protein structure analysis confirmed variant impacts on LAL enzyme function. Notably, this study marks the first analysis of rs1051338 and rs116928232 in a healthy Mexican mestizo population.
Assuntos
Frequência do Gene , Polimorfismo de Nucleotídeo Único , Esterol Esterase , Humanos , México/epidemiologia , Masculino , Feminino , Esterol Esterase/genética , Adulto , Polimorfismo de Nucleotídeo Único/genética , Pessoa de Meia-Idade , Adulto JovemRESUMO
INTRODUCTION: Current literature lacks consensus on initial assessments and routine follow-up care of patients with alpha-mannosidosis (AM). A Delphi panel was conducted to generate and validate recommendations on best practices for initial assessment, routine follow-up care, and integrated care coordination of patients with AM. METHODS: A modified Delphi method involving 3 rounds of online surveys was used. An independent administrator and 2 nonvoting physician co-chairs managed survey development, anonymous data collection, and analysis. A multidisciplinary panel comprising 20 physicians from 12 countries responded to 57 open-ended questions in the first survey. Round 2 consisted of 11 ranking questions and 44 voting statements. In round 3, panelists voted to validate 60 consensus statements. The panel response rate was ≥95% in all 3 rounds. Panelists used 5-point Likert scales to indicate importance (score of ≥3) or agreement (score of ≥4). Consensus was defined a priori as ≥75% agreement with ≥75% of panelists voting. RESULTS: Consensus was reached on 60 statements, encompassing 3 key areas: initial assessments, routine follow-up care, and treatment-related follow-up. The panel agreed on the type and frequency of assessments related to genetic testing, baseline evaluations, quality of life, biochemical measures, affected body systems, treatment received, and integrated care coordination in patients with AM. Forty-nine statements reached 90% to 100% consensus, 8 statements reached 80% to 85% consensus, and 1 statement reached 75% consensus. Two statements each reached consensus on 15 baseline assessments to be conducted at the initial follow-up visit after diagnosis in pediatric and adult patients. CONCLUSION: This is the first Delphi study providing internationally applicable, best-practice recommendations for monitoring patients with AM that may improve their care and well-being.
Assuntos
Consenso , Técnica Delphi , alfa-Manosidose , Humanos , alfa-Manosidose/terapia , alfa-Manosidose/diagnóstico , Inquéritos e Questionários , Prestação Integrada de Cuidados de Saúde/normasRESUMO
The Ibero-American Network of Pharmacogenetics and Pharmacogenomics (RIBEF) studies Latin American populations to benefit from the implementation of personalized medicine. Since 2006, it has studied ethnicity to apply pharmacogenetics knowledge in autochthonous populations of Latin America, considering ancestral medicine. The meeting 'Pharmacogenetics: ethnicity, Treatment and Health in Latin American Populations' was held in Mexico City, Mexico, and presented the relevance of RIBEF collaboration with Latin American researchers and the governments of Mexico, Spain and the Autonomous Community of Extremadura. The results of 17 years of uninterrupted work by RIBEF, the Declaration of Mérida/T'Hó and the call for the Dr José María Cantú Award for studies focused on the pharmacogenetics of native populations in Latin America were presented.
Assuntos
Etnicidade , Farmacogenética , Humanos , Etnicidade/genética , América Latina/epidemiologia , México/epidemiologia , Farmacogenética/métodos , Medicina de PrecisãoRESUMO
Resumen OBJETIVO: Identificar las causas de hidrops fetal no inmunitario en un hospital obstétrico de referencia del Occidente de México. MATERIALES Y MÉTODOS: Estudio de serie de casos, con un muestreo no probabilístico por conveniencia, llevado a cabo de octubre de 2014 a septiembre de 2015 al que se incluyeron pacientes (entre las 15 y 38 semanas de embarazo), mayores de edad (en casos de menores de edad se solicitó consentimiento informado a los padres o tutores), con diagnóstico de hidrops fetal por ultrasonido obstétrico. Para el análisis estadístico se generó una base de datos en Excel y se aplicó estadística descriptiva. RESULTADOS: Se reunieron 33 embarazadas en quienes el hidrops fetal no inmunitario fue el más frecuente (n = 31) y la causa idiopática más común (n = 10) seguida por errores innatos del metabolismo, alteraciones cromosómicas y cardiacas (n = 6 de cada una). Posteriormente, las causas hematológicas (n = 4), linfáticas y sindrómicas (n = 3 de cada una), y las infecciosas y tumorales (n = 1 de cada una). En este estudio los errores innatos del metabolismo (específicamente síndrome Sly) tuvieron una frecuencia superior a la referida en la bibliografía. CONCLUSIONES: Los errores innatos del metabolismo, las anomalías cromosómicas y cardiacas fueron la segunda causa más frecuente de hidrops fetal no inmunitario. Se sugiere tener en cuenta las causas metabólicas en el enfoque diagnóstico del hidrops fetal, sobre todo para el establecimiento del tratamiento temprano.
Abstract OBJECTIVE: To identify the causes of nonimmune fetal hydrops fetalis in an obstetric referral hospital in Western Mexico. MATERIALS AND METHODS: Case series study, with non-probabilistic sampling by convenience, carried out from October 2014 to September 2015 which included patients (between 15 and 38 weeks of pregnancy), of legal age (in cases of minors, informed consent was requested from parents or guardians), with a diagnosis of fetal hydrops fetalis by obstetric ultrasound. For statistical analysis, an Excel database was generated and descriptive statistics were applied. RESULTS: Thirty-three pregnant women were included, in whom non-immune fetal hydrops fetalis was the most frequent (94%) and idiopathic was the most common cause (n = 10), followed by inborn errors of metabolism, chromosomal and cardiac alterations (n = 6 each). This was followed by hematologic (n = 4), lymphatic and syndromic causes (n = 3 each), and infectious and tumor causes (n = 1 each). In this study, inborn errors of metabolism (specifically Sly syndrome) had a higher frequency than that reported in the literature. CONCLUSIONS: Inborn errors of metabolism, chromosomal and cardiac abnormalities were the second most frequent cause of nonimmune fetal hydrops. It is suggested that metabolic causes be taken into account in the diagnostic approach to fetal hydrops, especially for the establishment of early treatment.
RESUMO
Sialidosis is a rare autosomal recessive disease that presents with progressive lysosomal storage of sialylated glycopeptides and oligosaccharides caused by homozygous or compound heterozygous sequence variants in the neuraminidase 1 (NEU1) gene. These sequence variants can lead to sialidosis type I and II; the latter is the most severe and presents prenatally or at early age. However, sialidosis diagnosis is challenging, especially in those health systems with limited resources of developing countries. Consequently, it is necessary to dip into high-throughput molecular diagnostic tools to allow for an accurate diagnosis with better cost-effectiveness and turnaround time. We report a 4-member pedigree segregating an ultrarare missense variant, c.1109A>G; p.Tyr370Cys, in NEU1 as detected by whole-exome sequencing. Two short-lived siblings, who presented with previously unreported clinical features from such a homozygous sequence variant, were diagnosed with sialidosis type II. Additionally, we present a novel molecular model exhibiting the consequences of the variant in the sialidase-1 tridimensional structure. This study allowed us to provide a definitive diagnosis for our patients, increase our understanding of this pathogenic variant, and improve genetic counseling.
RESUMO
The spinocerebellar ataxia type 2 is a neurodegenerative disease with autosomal dominant inheritance; clinically characterized by progressive cerebellar ataxia, slow ocular saccades, nystagmus, ophthalmoplegia, dysarthria, dysphagia, cognitive deterioration, mild dementia, peripheral neuropathy. Infantile onset is a rare presentation that only has been reported in four instances in the literature. In the present work a boy aged 5 years 7 months was studied due to horizontal gaze-evoked nystagmus, without saccades, ataxic gait, dysarthria, dysphagia, dysmetria, generalized spasticity mainly pelvic, bilateral Babinsky. The mother aged 27 years-old presented progressive cerebellar ataxia, dysarthria, dysmetria, dysdiadochokinesis, limb ataxia and olivopontocerebellar atrophy. The molecular analysis was made by identifying the expansion repeats in tandem by long PCR to analyze the repeats in the ATXN2 gene. We found an extreme CAG expansion repeats of ~884 repeats in the child. We describe a Mexican child affected by SCA2 with an infantile onset, associated with a high number of CAG repeats previously no reported and anticipation phenomenon.
RESUMO
Blau syndrome (BS) is a rare, chronic autoinflammatory disease with onset before age 4 and mainly characterised by granulomatous arthritis, recurrent uveitis, and skin rash. Sporadic (also known as early-onset sarcoidosis) or familial BS is caused by gain-of-function mutations in the NOD2 gene, which encodes for a multi-task protein that plays a crucial role in the innate immune defense. We report on three Mexican patients clinically diagnosed with BS who exhibited a likely pathogenic variant in NOD2 as revealed by whole-exome sequencing (WES) and Sanger sequencing: two variants (c.1000 C > T/p.Arg334Trp and c.1538 T > C/p.Met513Thr) lie in the ATP/Mg2+ binding site, whereas the other (c.3019dupC/p.Leu1007ProfsTer2) introduces a premature stop codon disrupting the last LRR domain (LRR9) formation; all three variants are consistent with gain-of-function changes. Interestingly, all these patients presented concomitant likely pathogenic variants in other inflammatory disease-related genes, i.e. TLR10, PRR12, MEFV and/or SLC22A5. Although the clinical presentation in these patients included the BS diagnostic triad, overall it was rather heterogeneous. It is plausible that this clinical variability depends partly on the patients' genetic background as suggested by our WES results. After this molecular diagnosis and given the absence of NOD2 mutations (demonstrated in two trios) and related symptoms in the respective parents (confirmed in all trios), patients 1 and 2 were considered to have sporadic BS, while patient 3, a sporadic BS-recurrent polyserositis compound phenotype. Altogether, our observations and findings underscore the overlapping among inflammatory diseases and the importance of determining the underlying genetic cause by high-throughput methods. Likewise, this study further reinforces a pathogenic link between the here found NOD2 variants and BS and envisages potential additive effects from other loci in these, and probably other patients.
Assuntos
Artrite/genética , Proteína Adaptadora de Sinalização NOD2/genética , Sarcoidose/genética , Sinovite/genética , Uveíte/genética , Adolescente , Artrite/imunologia , Criança , Códon sem Sentido , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Domínios Proteicos/genética , Sarcoidose/imunologia , Sinovite/imunologia , Uveíte/imunologia , Sequenciamento do ExomaRESUMO
Mucopolysaccharidoses (MPS) are a group of genetic disorders, each resulting from the deficiency of one of the lysosomal enzymes that catabolizes mucopolysaccharides. For the accurate diagnosis of the disease, the quantification of a specific enzymatic activity is needed. In the present study, we analyzed seven MPS over several periods of time ranging from 2 to 5 years in a reference center in Mexico. During this time, a total of 761 samples belonging to 505 individuals with suspected MPS were analyzed. A total of 198 (26.01%) positive results were found. Among these, MPS IVA accounted for the highest frequency of positive results (49.10%), followed by MPS III (17.69%, IIIA: 11.80% and IIIB: 5.89%). Adjusting for the number of births per year, the estimated incidence per 100,000 births for MPS analyzed were as follows: MPS I: 0.19, MPS II: 0.15, MPS IIIA: 0.26, MPS IIIB: 0.13, MPS IVA: 1.10, MPS VI: 0.17 and MPS VII: 0.23, and the combined estimated incidence of MPS was 2.23 per 100,000 births; however, this incidence seems to be highly underestimated when compared with the results of newborn screenings.
RESUMO
Williams-Beuren syndrome (WBS) has a prevalence of 1/7500-20000 live births and results principally from a de novo deletion in 7q11.23 with a length of 1.5 Mb or 1.8 Mb. This study aimed to determine the frequency of 7q11.23 deletion, size of the segment lost, and involved genes in 47 patients with a clinical diagnosis of WBS and analysed by fluorescence in situ hybridization (FISH); among them, 31 had the expected deletion. Micro-array comparative genomic hybridization (aCGH) confirmed the loss in all 18 positive-patients tested: 14 patients had a 1.5 Mb deletion with the same breakpoints at 7q11.23 (hg19: 72726578-74139390) and comprising 24 coding genes from TRIM50 to GTF2I. Four patients showed an atypical deletion: two had a 1.6 Mb loss encompassing 27 coding genes, from NSUN5 to GTF2IRD2; another had a 1.7 Mb deletion involving 27 coding genes, from POM121 to GTF2I; the remaining patient presented a deletion of 1.2 Mb that included 21 coding genes from POM121 to LIMK1. aCGH confirmed the lack of deletion in 5/16 negative-patients by FISH. All 47 patients had the characteristic facial phenotype of WBS and 45 of 47 had the typical behavioural and developmental abnormalities. Our observations further confirm that patients with a classical deletion present a typical WBS phenotype, whereas those with a high (criteria of the American Association of Pediatrics, APP) clinical score but lacking the expected deletion may harbour an ELN point mutation. Overall, the concomitant CNVs appeared to be incidental findings.
Assuntos
Deleção Cromossômica , Cromossomos Humanos Par 7/genética , Hibridização Genômica Comparativa/métodos , Hibridização in Situ Fluorescente/métodos , Síndrome de Williams/genética , Adolescente , Criança , Pré-Escolar , Bandeamento Cromossômico , Feminino , Humanos , Lactente , Cariotipagem , Masculino , México , Síndrome de Williams/diagnósticoRESUMO
BACKGROUND: Disruptive amniotic band sequence (DABS) is a sporadic, non-familial disorder with unclear etiology. Diagnosis is based on clinical features because there is currently no reliable laboratory diagnostic tests. OBJECTIVE: We describe six cases of DABS with severe craniofacial deformations, three with and three without classical constrictive limb deformation. RESULTS: The craniofacial deformities were delimited by peripheral sharply demarcated scarring. CONCLUSION: When a sharply demarcated linear disruptive craniofacial lesion is observed, DABS should be considered despite the absence of constrictive limb scarring.
Assuntos
Síndrome de Bandas Amnióticas/complicações , Síndrome de Bandas Amnióticas/patologia , Anormalidades Craniofaciais/etiologia , Anormalidades Craniofaciais/patologia , Feminino , Humanos , Lactente , Recém-Nascido , MasculinoRESUMO
The original version of this article unfortunately contained two mistakes in the Abstract and the Discussion sections that the authors would like to correct.
RESUMO
Preeclampsia is a condition associated with high rates of maternal-fetal morbidity and mortality. It usually occurs in 3-10% of nulliparous women and 18% of previously affected women. Different lines of evidence have demonstrated the role of the father in the onset of preeclampsia. The placenta is the cornerstone of preeclampsia and poses important paternal genetic determinants; in fact, the existence of a "paternal antigen" has been proposed. Nulliparity is a well-known risk factor. Change of partner to a woman without history of preeclampsia increases the risk; however, this change decreases in women with history of the condition. High interval between pregnancies, short sexual intercourse before pregnancy, and conception by intracytoplasmic sperm injection suggest a limited exposure to the so-called paternal antigen. A man who was born from a mother with preeclampsia also increases the risk to his partner. Not only maternal but also paternal obesity is a risk factor for preeclampsia. Fetal HLA-G variants from the father increased the immune incompatibility with the mother and are also significantly associated with preeclampsia in multigravida pregnancies. An analysis of a group of Swedish pregnant women showed that the risk for preeclampsia is attributable to paternal factors in 13% of cases, which could be related to genetic interactions with maternal genetic factors. This review aimed to evaluate the evidences of the father's contribution to the onset of preeclampsia and determine the importance of including them in future studies.
RESUMO
INTRODUCTION: Recurrent spontaneous abortion (RSA) is a multifactorial condition that occurs with a frequency of 0.2-5% in women of reproductive age. Among genetic factors, the single nucleotide polymorphism (SNP) G1733A in the androgen receptor (AR) gene has been associated with its presence in Greek and Iranian populations. Therefore, the aim of this study is to determine its possible association with RSA in this population. PATIENTS AND METHODS: A total of 156 Mexican RSA (with at least 2 consecutive abortions) unrelated patients and 152 unrelated healthy women were included, the presence of karyotype anomalies in the parents as well as uterine anomalies as well as antiphospholipid antibodies was excluded in patients; while all the controls presented at least two healthy pregnancies and no abortion. In all the included women, the presence of the SNP G1733A was determined by restriction fragment length polymorphism (RFLP) technique. RESULTS: No significant differences were observed in age between groups. The genotype GG, GA, and AA had a frequency of 0.70, 0.27, and 0.03 in patients and of 0.89, 0.10, and 0.01 in controls [corrected] (p < 0.001); while the A allele frequency was of 0.06 and 0.16 in controls and patients, respectively (p < 0.0001). The difference in allele frequency increased 10-15% when patients with primary RSA (with no live births) and with at least three abortions were included. CONCLUSIONS: The SNP G1733A of the AR gene is significantly associated with RSA in Mexican patients. These results coincide with previous reports in other populations.
Assuntos
Aborto Habitual/genética , Polimorfismo de Nucleotídeo Único , Receptores Androgênicos/genética , Adolescente , Adulto , Estudos de Casos e Controles , Feminino , Predisposição Genética para Doença , Humanos , México , Gravidez , Adulto JovemRESUMO
INTRODUCTION: GATA2 mutations are associated with several conditions, including Emberger syndrome which is the association of primary lymphedema with hematological anomalies and an increased risk for myelodysplasia and leukemia. OBJECTIVE: To describe a family with Emberger syndrome with incomplete penetrance. METHODS: A DNA sequencing of GATA2 gene was performed in the parents and offspring (five individuals in total). RESULTS: The family consisted of 5 individuals with a GATA2 null mutation (c.130G>T, p.Glu44*); three of them were affected (two of which were deceased) while two remained unaffected at the age of 40 and 13 years old. The three affected siblings (two boys and one girl) presented with lymphedema of the lower limbs, recurrent warts, epistaxis and recurrent infections. Two died due to hematological abnormalities (AML and pancytopenia). In contrast, the two other family members who carry the same mutation (the mother and one brother) have not presented any symptoms and their blood tests remain normal. DISCUSSION: Incomplete penetrance may indicate that GATA2 haploinsufficiency is not enough to produce the phenotype of Emberger syndrome. It could be useful to perform whole exome or genome sequencing, in cases where incomplete penetrance or high variable expressivity is described, in order to probably identify specific gene interactions that drastically modify the phenotype. In addition, skewed gene expression by an epigenetic mechanism of gene regulation should also be considered.
Assuntos
Fator de Transcrição GATA2/genética , Estudos de Associação Genética , Mutação , Penetrância , Adolescente , Adulto , Criança , Pré-Escolar , Análise Mutacional de DNA , Feminino , Heterozigoto , Humanos , Masculino , Linhagem , Fenótipo , SíndromeAssuntos
Transtornos Cromossômicos/genética , Cromossomos Humanos Par 8 , Pré-Escolar , Transtornos Cromossômicos/diagnóstico , Cromossomos Humanos Par 8/genética , Feminino , Humanos , Hibridização in Situ Fluorescente , Deficiência Intelectual , Cariotipagem , México , Análise de Sequência com Séries de OligonucleotídeosRESUMO
Chitotriosidase (CHIT, EC 3.2.1.14) is an enzyme secreted by activated macrophages with the ability to hydrolyze the chitin of pathogens. The high activity of this enzyme has been used as a secondary biomarker of response to treatment in patients with Gaucher disease (OMIM 230800). Within the world's population, approximately 6% is homozygous and 35% is heterozygous for the most common polymorphism in the CHIT1 gene, a 24-bp duplication (dup-24 bp), with homozygosity of this duplication causing inactivation of the enzyme but without major consequences for health. To determine the frequency of the dup-24 bp CHIT1 gene in indigenous populations from Mexico, 692 samples were analyzed: Purepecha (49), Tarahumara (97), Huichol (97), Mayan (139), Tenek (97), and Nahua (213). We found that the groups were in Hardy-Weinberg equilibrium. The dup-24 bp allele frequency was found to be (in order of highest to lowest) 37% (Mayan), 34% (Huichol and Nahua), 33% (Purepecha), 31% (Tenek), and 29% (Tarahumara).
RESUMO
The narrow standard age range of menopause, â¼50 yr, belies the complex balance of forces that govern the underlying formation and progressive loss of ovarian follicles (the "ovarian reserve" whose size determines the age of menopause). We show here the first quantitative graph of follicle numbers, distinguished from oocyte counts, across the reproductive lifespan, and review the current state of information about genetic and epidemiological risk factors in relation to possible preservation of reproductive capacity. In addition to structural X-chromosome changes, several genes involved in the process of follicle formation and/or maintenance are implicated in Mendelian inherited primary ovarian insufficiency (POI), with menopause before age 40. Furthermore, variants in a largely distinct cohort of reported genes-notably involved in pathways relevant to atresia, including DNA repair and cell death-have shown smaller but additive effects on the variation in timing of menopause in the normal range, early menopause (age <45), and POI. Epidemiological factors show effect sizes comparable to those of genetic factors, with smoking accounting for about 5% of the risk of early menopause, equivalent to the summed effect of the top 17 genetic variants. The identified genetic and epidemiological factors underline the importance of early detection of reproductive problems to enhance possible interventions.
Assuntos
Menopausa/genética , Menopausa/fisiologia , Ovário/fisiologia , Envelhecimento/genética , Envelhecimento/fisiologia , Feminino , Humanos , Pessoa de Meia-IdadeRESUMO
Human leukocyte antigen is a class I HLA classic molecule that is preferentially expressed in cytotrophoblast cells and participates in tolerance and immune system suppression. The expression of HLA-G is induced in viral infections, autoimmune disorders, and cancers. Currently, HLA-G is considered a biomarker in the diagnosis, prognosis, and therapy of cancer.
RESUMO
INTRODUCTION: The cystathionine beta synthase (CBS) gene plays an important role in homocysteine metabolism because it catalyzes the first step of the transsulfuration pathway, during which homocysteine is converted to cystathionine. Polymorphisms of CBS have been associated with cancer. MATERIAL AND METHODS: We examined the role of the 844ins68 polymorphism by comparing the genotypes of 371 healthy Mexican women with the genotypes of 323 Mexican women with breast cancer (BC). RESULTS: The observed genotype frequencies for controls and BC patients were 1% and 2% for Ins/Ins, 13% and 26% for W/Ins, and 86% and 72% for W/W, respectively. We found that the odds ratio (OR) was 2.2, with a 95% confidence interval (95% CI) of 1.5-3.3, p = 0.0001. The association was also evident when comparing the distribution of the W/Ins-Ins/Ins genotypes in patients in the following categories: 1) menopause and high γ-glutamyltransferase (GGT) levels (OR of 2.17, 95% CI: 1.17-4.26, p = 0.02), 2) chemotherapy response and high lactate dehydrogenase (LDH) levels (OR 2.2, 95% CI: 1.08-4.4, p = 0.027), 3) chemotherapy response and high GGT levels (OR 2.46, 95% CI: 1.2-4.8, p = 0.007), and 4) body mass index (BMI) and III-IV tumor stage (OR 3.2, 95% CI: 1.2-8.3, p = 0.013). CONCLUSIONS: We conclude that the genotypes W/Ins-Ins/Ins of the 844ins68 polymorphism in the CBS gene contribute significantly to BC susceptibility in the analyzed sample from the Mexican population.