Duchenne muscular dystrophy in a developing country: challenges in management and genetic counseling.

BACKGROUND AND OBJECTIVE: Multidisciplinary management of Duchenne Muscular Dystrophy (DMD) has achieved outstanding results in developed nations. We aimed to describe the status of diagnosis and management of DMD in a developing country through the experience of non-profit organizations. METHODS: A Multistate, multiple-source, population-based survey was performed from medical records of 432 patients. Data were retrospectively collected, reviewed and curated by health specialists; including clinical features, age at first symptoms, age at diagnosis, disease progression and management, family history, education, age and cause of death. RESULTS: There is a delay in noticing first symptoms and it did not diminish over the past 20 years. Less than 30% of patients obtained definite diagnosis and most of them are in physiotherapy programs but not under steroid treatment. In our study, family history does not anticipate recognition of symptoms compared to sporadic cases (p = 0.05). Approximately 93.33% of our patients attended to education programs. Mean age at death was 18.94 +/- 6.73 years and the most frequent cause was pneumonia. CONCLUSION: Delayed diagnosis of DMD in Mexico is mainly caused by the late detection of first symptoms. There is no difference in early detection of symptoms between familiar and sporadic cases. Lifespan of patients in our cohort is reduced compared to developed countries. The late diagnosis and low percentage of definite cases may affect patient management and genetic counseling and could also preclude participation of patients into novel clinical trials.

Molecular characterization of a patient with 3p deletion syndrome and a review of the literature.

3p deletion syndrome is a rare disorder involving developmental delay, dysmorphic physical features, and growth retardation. Molecular mapping of several cases in the literature have identified a critical region on chromosome 3p26. We present a child patient with characteristic features of 3p deletion syndrome and a de novo unbalanced translocation involving chromosomes 3 and 13. Fine mapping of this rearrangement using fluorescence in situ hybridization (FISH) and array-based comparative genomic hybridization (aCGH) revealed an unbalanced abnormality including a 4.5 Mb terminal deletion of chromosome 3p, telomeric to ITPR1 on 3p26.2, which was not previously identified with routine cytogenetic analysis. In addition, these investigations confirmed and refined the boundaries of a 26.5 Mb deletion of chromosome 13. This study confirms the minimal candidate region for 3p deletion syndrome, provides further evidence implicating haploinsufficiency of CNTN4 in the disorder, and demonstrates the utility of high-resolution investigations of rare chromosomal rearrangements.

SED-brachydactyly and distinctive speech: report of two new cases.

We describe two unrelated patients and the mother of one of them showing clinical and radiological features as those previously described in the spondyloepiphyseal dysplasia-brachydactyly and distinctive speech (SED-BDS, also named Fantasy Island syndrome or Tattoo dysplasia) clinically characterized by short stature with acral shortness, distinctive face, mild blepharophimosis, upslanted palpebral fissures, abundant eyebrows and eyelashes, thick and abundant hair and coarse voice; and radiologically by brachymetacarpalia, brachymetatarsalia and brachyphalangia of all fingers and toes, short and broad long bones with normal morphology and small pelvis. The clinical and radiological features present in mother and son suggest a probable autosomal dominant mode of inheritance and variable expressivity.

Constitutional duplication 11q23 de novo involving the MLL gene.

We report a child with mental retardation, brain anomalies and congenital heart defect. His karyotype, after G-banding and FISH with a whole chromosome probe for chromosome 11 and a locus-specific probe for the MLL gene, was 46,XY,dup(11)(q23q23).ish dup(11)(q23q23)(wcp11+, MLL++) de novo; i.e., he had a pure partial 11q23 duplication. Clinical and cytogenetic findings of the present case were compared with the 7 previously reported cases with pure partial trisomy 11q; in 6/8 cases the region 11q23 was involved. We conclude that the scarce number of cases and their heterogeneity do not allow to establish a reliable genotype-phenotype correlation.

Association analysis of the Gln223Arg polymorphism in the human leptin receptor gene, and traits related to obesity in Mexican adolescents.

Polymorphisms of leptin receptor (LEPR) may contribute to a common form of obesity and, as a consequence, obesity-related diseases. We evaluated the potential role of genetic variation at the LEPR gene in heart sympathetic activity and other traits related to obesity in Mexican adolescents. Adolescents aged between 12 and 17 years, with steady body weight for the last 3 months were included. We evaluated anthropometric measurements, blood pressure, seric glucose, insulin, leptin levels, heart sympathetic activity (by electrocardiograph monitoring at rest), and the Gln223Arg and Pro1019Pro LEPR polymorphisms in each subject. In total, 103 adolescents (55 obese and 48 nonobese) were included. The group of obese adolescents showed higher sympathetic activity, blood pressure, glucose, insulin, and leptin levels. The genotype frequencies for the two polymorphisms were found to be in Hardy-Weinberg equilibrium. There was no difference in the genotype frequencies for Gln223Arg or Pro1019Pro polymorphisms between obese and nonobese adolescents. However, there was a higher prevalence of Gln223 allele among subjects with higher insulin levels (0.72 vs 0.57; P = 0.04 for adolescents with insulin levels higher and lower than 100 pmol/l, respectively). According to Gln223Arg polymorphism, those with Gln allele (Gln/Gln and Gln/Arg) had higher heart sympathetic activity, body fat percentage, and leptin levels. To conclude, our results support the hypothesis that Gln223Arg polymorphism of LEPR in Mexican adolescents is associated with haemodynamic and metabolic disturbances related to obesity.

DNA polymorphism analysis of candidate genes for type 2 diabetes mellitus in a Mexican ethnic group.

Type 2 diabetes mellitus is a complex metabolic disorder resulting from the action and interaction of many genetic and environmental factors. It has been reported that polymorphisms in genes involved in the metabolism of glucose are associated with the susceptibility to develop type 2 diabetes mellitus. Although the risk of developing type 2 diabetes mellitus increases with age, as well as with obesity and hypertension, its prevalence and incidence are different among geographical regions and ethnic groups. In Mexico, a higher prevalence and incidence has been described in the south of the country, and differences between urban and rural communities have been observed. We studied 73 individuals from Santiago Jamiltepec, a small indigenous community from Oaxaca State, Mexico. This population has shown a high prevalence of type 2 diabetes mellitus, and the aim of this study was to analyze the relationship between the Pst I (insulin gene), Nsi I (insulin receptor gene) and Gly972Arg (insulin receptor substrate 1 gene) polymorphisms and type 2 diabetes mellitus, obesity and hypertension in this population. Clinical evaluation consisted of BMI and blood pressure measurements, and biochemical assays consisted of determination of fasting plasma insulin and glucose levels. PCR and restriction enzyme digestion analysis were applied to genomic DNA to identify the three polymorphisms. From statistical analysis carried out here, individually, the Pst I, Nsi I and Gly972Arg polymorphisms were not associated with the type 2 diabetes, obese or hypertensive phenotypes in this population. Nevertheless, there was an association between the Nsi I and Pst I polymorphisms and increased serum insulin levels.

Familial iridogoniodysgenesis and skeletal anomalies: a probable new autosomal recessive disorder.

Three sibs with congenital glaucoma, skeletal anomalies, and peculiar facial appearance were studied. At birth, enlarged eyes and corneae were present in the proposita and her two brothers due to congenital glaucoma secondary to iridogoniodysgenesis (IGD). The purpose of this article is to describe the second familial case with IGD and skeletal anomalies as the family previously described by García-Cruz et al. in 1990, corroborating this new distinct dysmorphic syndrome with probable autosomal recessive inheritance.

Second female case of Myhre syndrome.

Myhre syndrome is a rare disorder characterized by low birthweight, short stature, mental retardation, facial dysmorphism (blepharophimosis, midfacial hypoplasia, prognathism), heart anomalies, muscle hypertrophy, decreased joint mobility and deafness. To date 11 male cases and only one female case have been reported. This paper describes the second female case and compares the clinical and radiological findings between female and male patients.