ABSTRACT
A síndrome de Prader-Willi (SPW) é uma desordem genética complexa, caracterizada por deleções, dissomia uniparental materna ou defeito no centro de imprinting no alelo paterno do cromossomo 15. As perdas de funções de genes específicos da região 15q11 afetam múltiplos sistemas corporais. O diagnóstico da SPW é difícil de ser realizado com base apenas no exame clínico e envolve a realização de diversas técnicas de biologia molecular para a completa elucidação da etiologia genética, tornando todo o processo laborioso, demorado e custoso. A realização de um teste molecular que permita um diagnóstico rápido e preciso é de vital importância para um melhor prognóstico para paciente. A coleta bem-sucedida de amostras e a extração de DNA de swabs são alternativas não invasivas e confiáveis, tanto para os pacientes quanto para os profissionais que realizarão a coleta destas amostras. Neste trabalho foi possível demonstrar um método simples de coleta de amostras e extração de DNA, que possui baixo custo, é eficaz, fácil e rápido, que fornece uma quantidade e qualidade suficiente de DNA para a execução do MS-HRM, qPCR e sequenciamento. Uma comparação dos procedimentos de extração mostra que o método simples de extração de NaCl é o mais adequado para extração de DNA de amostra bucal coletada através de swab. Neste trabalho foi demonstrado um método simples de coleta de amostras através do swab e extração de DNA com baixo custo e boa qualidade do DNA.
Prader-Willi syndrome (PWS) is a complex disorder, uniparental by deletions, dissociated from no imprint defect in any of the chromosomes 15. As gene variants of the genetic region of the 15q11 region, the diagnosis of PWS is challenging to perform based on clinical examination alone. It involves the performance of several molecular biology techniques for the complete elucidation of genetics, determining the entire laborious, time-consuming, and costly process. The performance of a molecular test allows a quick diagnosis, which is vital for a better prognosis for the patient. Successful sample collection and DNA collection from swabs are non-invasive alternatives for patients and practitioners performing probable sample collection. In this work, it was possible to demonstrate a simple sample collection and DNA method, which has a low cost, is effective, easy, and fast, and provides a sufficient quantity and quality of DNA for the execution of MS-HRM, qPCR, and sequencing. A comparison of the extraction procedures shows that the simple NaCl extraction method is the most appropriate for extracting DNA from a buccal sample collected via swab. In this work, a simple method for swab sampling and extracting DNA was demonstrated, with low cost and good DNA quality.
Subject(s)
Humans , Prader-Willi Syndrome/diagnosis , Triage , DNA Methylation , Molecular Diagnostic TechniquesABSTRACT
ABSTRACT Prader-Willi syndrome (PWS) is a genetic disorder caused by the absence of gene expression in the 15q11.2-q13 paternal chromosome. Patients with PWS develop hypothalamic dysfunction that can lead to various endocrine changes such as: obesity, growth hormone deficiency, hypogonadism, hypothyroidism, adrenal insufficiency and low bone mineral density. In addition, individuals with PWS have increased risk of developing type 2 diabetes mellitus. This review summarizes and updates the current knowledge about the prevention, diagnosis and treatment of endocrine manifestations associated with Prader Willi syndrome, especially diagnosis of growth hormone deficiency, management and monitoring of adverse effects; diagnosis of central adrenal insufficiency and management in stressful situations; screening for central hypothyroidism; research and treatment of hypogonadism; prevention and treatment of disorders of glucose metabolism. Careful attention to the endocrine aspects of PWS contributes significantly to the health of these individuals. Arch Endocrinol Metab. 2020;64(3):223-34
Subject(s)
Humans , Prader-Willi Syndrome/complications , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/genetics , Diabetes Mellitus/etiology , Hypogonadism/etiology , Hypothyroidism/etiology , Obesity/etiologyABSTRACT
RESUMO Objetivo: Realizar uma revisão sobre a Síndrome de Prader-Willi (SPW) com base nas publicações mais recentes e fornecer recomendações ao pediatra geral para diagnóstico precoce e seguimento. Fonte de dados: Artigos publicados nas bases Pubmed e SciELO. A pesquisa não foi limitada a um período e incluiu todos os artigos das bases de dados. Síntese dos dados: A SPW é uma síndrome genética rara, resultante da perda do imprinting gênico expresso no cromossomo paterno 15q11-q13, sendo caracterizada por alterações endocrinológicas, como deficiência de hormônio de crescimento, obesidade, insuficiência adrenal central, hipotireoidismo, hipogonadismo, além de alterações comportamentais e déficit intelectual. Há outras comorbidades associadas, como distúrbios de sono, escoliose, constipação, problemas dentários e alterações de coagulação. O protocolo de seguimento da SPW do Instituto da Criança da Universidade de São Paulo se baseia em quarto pilares principais: dieta, exercício físico, terapia com hormônio de crescimento humano recombinante (rhGH) e manejo comportamental e cognitivo. A dieta deve ser restrita a 900 kcal/dia, de acordo com a Pirâmide Alimentar do Prader-Willi, e o exercício físico deve ser diário, aeróbico e postural. A terapia com rhGH é fortemente recomendada pela literatura científica internacional e deve ser iniciada assim que for realizado o diagnóstico da síndrome. O manejo do comportamento é realizado com estratégias para estabelecer rotina e regras. Conclusões: Se a SPW se tornar mais familiar ao pediatra geral, o diagnóstico e o tratamento começarão mais precocemente, o que irá melhorar a qualidade de vida e os cuidados desses pacientes.
ABSTRACT Objective: To carry out a review about Prader-Willi Syndrome based on the most recent data about the subject and to give recommendation for the general pediatricians for early diagnoses and follow-up. Data sources: Scientific articles in the PubMed and SciELO databases. The research was not limited to a specific time period and included all articles in such databases. Data synthesis: The Prader-Willi Syndrome (PWS) is a rare genetic disorder resulting from the loss of imprinted gene expression within the paternal chromosome 15q11-q13. PWS is characterized by endocrine abnormalities, such as growth hormone (GH) deficiency, obesity, central adrenal insufficiency, hypothyroidism, hypogonadism and complex behavioral and intellectual difficulties. PWS individuals also may present other comorbidities, such as sleep disorders, scoliosis, constipation, dental issues and coagulation disorders. The follow-up protocol of the Children's Institute at Universidade de São Paulo is based on four main pillars: diet, exercise, recombinant human growth hormone (rhGH) therapy and behavioral and cognitive issues. The diet must include a caloric restriction of 900 kcal/day, according to the Prader-Willi Eating Pyramid and exercise plan is focused on daily aerobic exercises and postural therapy. The rhGH therapy is highly recommended by the international scientific literature and must be started as soon as the diagnostic is made. The management of behavioral issues is based on strategies to establish routine and rules. Conclusions: If the general pediatrician becomes more familiar with PWS, the diagnosis and treatment will start earlier, which is essential to improve the quality of life and care for these individuals.
Subject(s)
Humans , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/therapy , Pediatrics , Practice Guidelines as TopicABSTRACT
SUMMARY Prader-Willi syndrome (PWS) is a genetic disorder frequently characterized by obesity, growth hormone deficiency, genital abnormalities, and hypogonadotropic hypogonadism. Incomplete or delayed pubertal development as well as premature adrenarche are usually found in PWS, whereas central precocious puberty (CPP) is very rare. This study aimed to report the clinical and biochemical follow-up of a PWS boy with CPP and to discuss the management of pubertal growth. By the age of 6, he had obesity, short stature, and many clinical criteria of PWS diagnosis, which was confirmed by DNA methylation test. Therapy with recombinant human growth hormone (rhGH) replacement (0.15 IU/kg/day) was started. Later, he presented psychomotor agitation, aggressive behavior, and increased testicular volume. Laboratory analyses were consistent with the diagnosis of CPP (gonadorelin-stimulated LH peak 15.8 IU/L, testosterone 54.7 ng/dL). The patient was then treated with gonadotropin-releasing hormone analog (GnRHa). Hypothalamic dysfunctions have been implicated in hormonal disturbances related to pubertal development, but no morphologic abnormalities were detected in the present case. Additional methylation analysis (MS-MLPA) of the chromosome 15q11 locus confirmed PWS diagnosis. We presented the fifth case of CPP in a genetically-confirmed PWS male. Combined therapy with GnRHa and rhGH may be beneficial in this rare condition of precocious pubertal development in PWS.
Subject(s)
Humans , Male , Child , Prader-Willi Syndrome/drug therapy , Puberty, Precocious/drug therapy , Gonadotropin-Releasing Hormone/therapeutic use , Human Growth Hormone/therapeutic use , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/genetics , Puberty, Precocious/complications , Recombinant Proteins/adverse effects , Recombinant Proteins/therapeutic use , DNA Methylation , Hormone Replacement Therapy/methodsABSTRACT
OBJECTIVE: this study aimed to investigate the cognitive and behavioral profiles, as well as the psychiatric symptoms and disorders in children with three different genetic syndromes with similar sociocultural and socioeconomic backgrounds. METHODS: thirty-four children aged 6 to 16 years, with Williams-Beuren syndrome (n = 10), Prader-Willi syndrome (n = 11), and Fragile X syndrome (n = 13) from the outpatient clinics of Child Psychiatry and Medical Genetics Department were cognitively assessed through the Wechsler Intelligence Scale for Children (WISC-III). Afterwards, a full-scale intelligence quotient (IQ), verbal IQ, performance IQ, standard subtest scores, as well as frequency of psychiatric symptoms and disorders were compared among the three syndromes. RESULTS: significant differences were found among the syndromes concerning verbal IQ and verbal and performance subtests. Post-hoc analysis demonstrated that vocabulary and comprehension subtest scores were significantly higher in Williams-Beuren syndrome in comparison with Prader-Willi and Fragile X syndromes, and block design and object assembly scores were significantly higher in Prader-Willi syndrome compared with Williams-Beuren and Fragile X syndromes. Additionally, there were significant differences between the syndromes concerning behavioral features and psychiatric symptoms. The Prader-Willi syndrome group presented a higher frequency of hyperphagia and self-injurious behaviors. The Fragile X syndrome group showed a higher frequency of social interaction deficits; such difference nearly reached statistical significance. CONCLUSION: the three genetic syndromes exhibited distinctive cognitive, behavioral, and psychiatric patterns. .
OBJETIVO: investigar o perfil cognitivo e comportamental, sintomas e transtornos psiquiátricos em crianças com três diferentes síndromes genéticas, com antecedentes socioculturais e socioeconômicos semelhantes. MÉTODOS: trinta e quatro crianças, entre 6 e 16 anos, com as síndromes de Williams-Beuren (n = 10), de Prader-Willi (n = 11) e do X-Frágil (n = 13), dos ambulatórios de Psiquiatria Infantil e Genética Médica, foram avaliadas cognitivamente pela Escala Wechsler de Inteligência para Crianças (WISC-III). Posteriormente, o QI total, o QI Verbal, o QI de Execução, os escores ponderados dos subtestes e a frequência de sintomas e transtornos psiquiátricos foram comparados entre as síndromes. RESULTADOS: diferenças significativas foram encontradas entre as síndromes quanto ao QI Verbal e os subtestes verbais e de execução. A análise Post-hoc demonstrou que os escores dos subtestes vocabulário e compreensão foram significativamente superiores na síndrome de Williams-Beuren em relação às síndromes de Prader-Willi e do X-Frágil, e os escores dos subtestes cubos e armar objetos foram significativamente superiores na síndrome de Prader-Willi em relação às síndromes de Williams-Beuren e do X-Frágil. Além disso, houve diferença significativa entre as síndromes quanto às características comportamentais e os sintomas psiquiátricos. O grupo com síndrome de Prader-Willi apresentou maior frequência de hiperfagia e comportamentos autolesivos. Já o grupo com síndrome do X-Frágil apresentou maior frequência do déficit da interação social. Esta diferença quase alcançou a significância estatística. CONCLUSÃO: as três síndromes genéticas ...
Subject(s)
Adolescent , Child , Female , Humans , Male , Cognition Disorders/psychology , Fragile X Syndrome/psychology , Intellectual Disability/psychology , Mental Disorders/psychology , Prader-Willi Syndrome/psychology , Williams Syndrome/psychology , Cognition , Cross-Sectional Studies , Cognition Disorders/genetics , Educational Status , Fragile X Syndrome/diagnosis , Income , Intellectual Disability/genetics , Mental Disorders/genetics , Prader-Willi Syndrome/diagnosis , Wechsler Scales , Williams Syndrome/diagnosisSubject(s)
Humans , Male , Female , Infant, Newborn , Chromosome Aberrations , Chromosome Deletion , Classical Lissencephalies and Subcortical Band Heterotopias , Diagnosis , In Situ Hybridization, Fluorescence , Angelman Syndrome/diagnosis , Kallmann Syndrome/diagnosis , Prader-Willi Syndrome/diagnosis , Smith-Magenis Syndrome/diagnosis , Williams Syndrome/diagnosisABSTRACT
El síndrome de Prader-Willi (SPW) es una enfermedad rara (incidencia 1:15.000), de causa genética, debido a una deleción del cromosoma 15 paterno en la región 15q 11-q13. Presenta alteraciones a nivel del hipotálamo con manifestaciones clínicas típicas, tales como hipotonía, hipogonadismo, facies típica y retraso mental que permiten su diagnóstico. El pronóstico de esta patología suele ser favorable si existe un adecuado manejo en la alimentación y un ambiente familiar con contención. Los odontólogos cumplen un rol fundamental en el mantenimienot y prevención de la salud bucal. El trabajo de interdisciplina es uno de los pilares fundamentales para un correcto abordaje y tratamiento odontológico, con el objetivo final de lograr la salud bucal que redundará en la salud sistémica de estas personas. En una unidad de atención odontológica especializada para niños portadores de discapacidad y riesgo médico se han atendido 16 pacientes durante los últimos 6 años, habiéndose confeccionado una guía de atención odontológica para pacientes con SPW basada en el plan de tratamiento odontopediátrico personalizado que tendrá en cuenta los signos y sintomatología sistémica y en especial las características bucodentales. De la atención clínica surgió la necesidad de realizar estudios específicos en la saliva de estos niños, por su característica especial, los cuales fueron realizados en interrelación con la universidad relacionada a la unidad de atención de pacientes especiales.
Subject(s)
Humans , Child , Dental Care for Children/methods , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/genetics , Prader-Willi Syndrome/therapy , Dental Care for Chronically Ill/methods , Oral Manifestations , Patient Care TeamABSTRACT
Prader–Willi syndrome (PWS) is neurogenetic disorder involving the imprinting mechanism at 15q11–13 region. We report a 4-year-old girl who was referred to our laboratory to be investigated for clinical obesity, mental deficiency and respiratory problems. The patient was born for non-consanguineous and healthy biological parents. After normal pregnancy, the patient was delivered by cesarean section at full term, with a birth weight of 2500 g, and the height and head circumference were unknown. In neonatal stage, she presented severe hypotonia with feeding problems. Her developmental progress was delayed. She walked and developed speech at the age of 3 years. Since the age of 3 years, she presented severe dental problems. Methylation study had confirmed the diagnosis, and for detecting etiology, fluorescence in situ hybridization using probes for small nuclear ribonucleoprotein polypeptide N (SNRPN), which map inside the chromosomal region 15q11–15q13, was necessary to confirm the 15q11–15q13 deletion of paternal chromosome 15, which is the predominant genetic defect in PWS. In conclusion, we report this case with an objective to reinforce the necessity of analysis of DNA methylation within the 15q11–13 region, which is an important tool for the correct diagnosis among children presenting with neonatal hypotonia, mental deficiency and obesity.
Subject(s)
Child, Preschool , Female , Humans , Intellectual Disability/etiology , In Situ Hybridization, Fluorescence/methods , Methylation , Obesity/etiology , Parents , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/epidemiology , Prader-Willi Syndrome/etiology , Prader-Willi Syndrome/genetics , Respiration/abnormalitiesABSTRACT
Introducción. El síndrome de Prader-Willi SPW) es un trastorno genético causado por la pérdida de expresión de genes de origen paterno en la región cromosómica compleja 15q11-q13. El fenotipo clínico ha sido bien caracterizado, especialmente relacionado con la disfunción hipotalámica. Aunque entre 20 a 30% de los pacientes con SPW tienen hipotiroidismo central (HC), no ha sido bien definida la función tiroidea durante los dos primeros años de vida. Objetivo: evaluar la función hipotalámica-pituitaria-tiroidea en lactantes con SPW. Diseño del estudio: 18 pacientes con SPW entre 0,16 y 2 años de edad fueron incluídos en un estudio prospectivo. El diagnóstico de SPW se basó en los hallazgos clínicos y en el análisis molecular. Se calcularon los escores de desviacion estándar (SDS) de la T4 total (T), T4 libre (L), T3 y TSH en suero en todos los pacientes incluídos en el estudio. Resultados: En 14 de los 18 pacientes con SPW, se encontraron niveles de T4T y/o T4L menores a -2 SDS (44,4 y 55,5%, respectivamente), mientras que solamente en 1 paciente con SPW el nivel de T3 estaba por debajo de -2 SDS. Conclusión: Este estudio muestra que la incidencia de HC es alta en lactantes con SPW. Los pediatras deben tener en cuenta el diagnostico de HC en este período crítico de la acción de la hormona tiroidea en el desarrollo neurológico (AU)
Introduction. Prader-Willi syndrome (PWS) is a genetic disorder caused by the loss of expression of paternally transcribed genes in a highly imprinted region of chromosome 15q11- q13. The clinical phenotype has been well characterized, mostly related to hypothalamic dysfunction. Even though central hypothyroidism (CH) has been documented in 20 to 30% of PWS patients, thyroid function has not been well characterized during the first 2 years of life. Objective: to evaluate hypothalamic-pituitary-thyroid function in infant PWS patients. Study design: Eighteen PWS patients, aged 0.16 to 2 years, were included in a prospective study. PWS diagnosis was based on clinical features and molecular analysis. Serum total (T) T4, free (F) T4, T3 and TSH standard deviation scores (SDS) were calculated in all PWS patients included in the study. Results: In 14 out of 18 PWS patients, serum TT4 and/or FT4 levels less than -2 SDS ( 44.4 and 55.5 %, respectively) were found, while in only 1 PWS patient serum T3 levels was below -2 SDS. Conclusion: This study shows that there is a high incidence of CH in infant PWS patients. Pediatricians should be aware of this diagnosis in this critical period of thyroid hormone action on neurological development (AU)
Subject(s)
Humans , Infant , Prader-Willi Syndrome/complications , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/genetics , Thyroid Hormones , Hypothalamo-Hypophyseal System/physiopathology , Hypothyroidism/diagnosis , Incidence , Prospective StudiesABSTRACT
El propósito del presente caso clínico es proponer una estrategia diagnóstica desde el paradigma de la función, se describe el caso de una niña portadora del síndrome de Prader - Willi que en el transcurso de su hospitalización se deriva al servicio de kinesiterapia para su control respiratorio, agregadamente se realiza la aplicación de pruebas funcionales, con el fin de conocer su perfil físico lo cual a juicio de los autores demuestra la necesidad de implementar una conducta.
This article describe the Prader - Willi syndrome in a girl in her hospitalization, her evaluations include physiotherapist. Agreguement the experience functionals test are not applied in the traditionally way in the utility diagnosis of physical therapy.
Subject(s)
Humans , Female , Child , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/physiopathologyABSTRACT
El síndrome de Prader Willi es una afección de niños y jóvenes caracterizada por obesidad, baja talla, oligofrenia, llanto débil o gemido, hipoplasia de los escrotos, testículos no descendidos, entre otros. En la pubertad se asocia a un desarrollo demorado e incompleto y a la aparición de diabetes mellitus y elevada excreción de gonadotropina. Presentamos en este trabajo a dos pacientes que cumplen estos criterios clínicos y que fueron estudiados en el Policlínico Docente ®19 de Abril¼. Se realiza una breve revisión bibliográfica del síndrome
Subject(s)
Prader-Willi Syndrome/diagnosisABSTRACT
Background: Prader-Willi syndrome (PWS) is a neurogenetic disease characterized by neonatal hypotonia, retarded mental and motor development, hypogonadism, hyperphagia, morbid obesity and dysmorphic facial features. It has an incidence of 1:12.000-15.000 newborns and is caused by abnormalities in genes located in 15q11q13. PWS is one of the most frequent genetic disorders and microdeletion syndromes. It is also the most common cause of obesity from genetic origin and it was the first disease in which imprinting and uniparental disomy were recognized as cause of genetic disorders. Seventy to seventy five percent of PWS cases are due to 15q11q13 deletions, 20-25percent to uniparental disomy and 1percent to mutations in the imprinting center. Aim: To analyze the clinical, genetic and molecular features of patients with PWS, seen at one institution. Patients and methods: Retrospective review of 45 patients (27 males) with PWS seen at the Genetics Outpatient Clinic at INTA. Results: Twenty three (51.1percent) patients had a delection, 13 (28.9percent) patients did not have a deletion. In nine patients, fluorescence in situ hybridization (FISH) study was not performed, therefore the presence of deletion was unknown. The clinical score was 8 points for patients younger than 3 years (n=11) and 11.5 points for patients older than 3 years (n=34); for patients aged 12 months or less, the clinical score was 7 points. Mean clinical score was 11 points for patients with deletion and 10 points for patients without deletion. Conclusions: Most patients with PWS have a deletion; the phenotype depends on age and the clinical score is useful for Chilean patients with PWS .
Subject(s)
Adolescent , Adult , Male , Humans , Female , Infant, Newborn , Infant , Child, Preschool , Child , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/genetics , Retrospective Studies , PhenotypeABSTRACT
El síndrome de Prader-Labhart-Willi (SPW) es una entidad que se asocia a trastornos respiratorios durante el sueño, lo que puede tener consecuencias fatales para la vida. Se presentan 3 pacientes con diagnóstico de SPW: 2 del sexo masculino y 1 del femenino. El diagnóstico en todos ellos fue confirmado después de los 2 años de edad. Los hallazgos clínicos más relevantes fueron: talla y peso corporal normal al nacimiento así como hipotonía muscular. En 2 pacientes la obesidad se inició después de los 2 años de edad y en el otro a los 18 meses de nacidos. La acromicria y retraso mental moderado estuvo presente en los 3 pacientes. Los resultados de los cariotipos por técnica de bandas fueron 46XY para los del sexo masculino y 46XX para la del femenino. Los 2 pacientes del sexo masculino presentaron episodios de apnea durante el sueño (Sleep Apnea Syndrome), lo que ocasionó el fallecimiento de ambos por paro respiratorio antes de los 12 años de edad. Se recomienda la vigilancia estrecha de estos pacientes, principalmente durante las infecciones respiratorias y las crisis de asma bronquial(AU)
Subject(s)
Humans , Male , Female , Child , Prader-Willi Syndrome/diagnosis , Respiratory Tract Infections/etiology , Sleep Apnea Syndromes/mortality , Obesity/etiology , Asthma , Intellectual DisabilityABSTRACT
Objetivo: o presente artigo objetiva relatar um caso de síndrome de Prader-Willi (SPW). Discussão do caso: paciente de 15 anos, sexo masculino, que se apresentou com as principais características da síndrome: a obesidade móbida, baixa estatura, hipogononadismo e fáceis característica . K. B.R. teve seu diagnóstico suspeito com 4 dias de vida, quando apresentou reflexos diminuídos, hipotonia, choro fraco e dificuldade em mamar. Com aproximadamente 2 anos, iniciou exagerado ganho de oeso, justificado pela sua fome insaciável. Aos 5 anos de idade fez-se o diagnóstico clínico de SPW, que posteriormente foi confirmado pela avaliação genética. Comentários: a SPW é um distúrbio neurocomportamental que geralmente surge por uma deleção proximal do cromossomo 15 durante a gametogênese paterna. A incidência varia de 1 caso em 25.000 até 1 caso em 10.000 nascidos vivos. O quadro clínico é caracterizado por hipotonia neonatal, retardo mental moderado, hiperfagia e obesidade precoce, hipogonadismo, acromicria e fáceis característca. O diagnóstico é feito clinicamente, podendo ser confirmado pela análise do segmento cromossômico 15q11-q13, por meio da metilação ou da hibridização in situ. Não há tratamento específico eficaz. Atualmente, a administração de hormônio do crescimento é a opção mais aceita.
Subject(s)
Humans , Male , Adolescent , Prader-Willi Syndrome/diagnosis , Prader-Willi Syndrome/epidemiology , Intellectual Disability , Hypogonadism , Obesity, MorbidABSTRACT
Paternal microdeletion of chromosome 15 at q11-q13 has been reported in 75% of Prader-Willi syndrome (PWS) patients in western countries. Diagnosis of PWS in Thailand is mainly based on clinical observation and, in some cases, confirmed by conventional cytogenetic analysis. Loss of a tiny segment in this region (microdeletion) has made it difficult to discriminate from the normal karyotype. An attempt to solve this problem has been made by using a high resolution chromosome culture. However, this method is a tedious and time-consuming technique which is suitable for only experienced cytogeneticists. We report molecular cytogenetic analysis for PWS in Thai patients using FISH in addition to standard GTG- banding chromosome analysis. Nine Thai patients clinically diagnosed or with a suspicion of PWS were investigated. The FISH probes consist of the region-specific probes (SNRPN or D15S10 probe) and two chromosome 15-specific control probes (D15Z1 centromeric and PML chromosome 15 long arm probe). Bright field and FISH programs of an automatic karyotyper were applied to facilitate the efficiency of the chromosome analysis. We found that 2 out of 9 patients showed a deletion at 15q11-q13 region by standard GTG chromosome analysis while 4 out of 9 patients showed a delation in this region by FISH. Consistent losing of SNRPN and D15S10 signals in FISH was observed in these patients. This forty-four per cent deletion is considerably lower than those reported from western countries. We propose that DNA methylation at SNRPN promoter as well as structural abnormalities in other chromosome regions might also play a role in the etiology of this disorder in Thais, which should be investigated further.
Subject(s)
Autoantigens , Child , Child, Preschool , Chromosome Banding , Chromosomes, Human, Pair 15/genetics , DNA Methylation , Female , Gene Deletion , Genetic Markers , Humans , In Situ Hybridization, Fluorescence/methods , Infant , Male , Phenotype , Prader-Willi Syndrome/diagnosis , Ribonucleoproteins, Small Nuclear/genetics , Thailand , snRNP Core ProteinsABSTRACT
BACKGROUND: Prader-Willi syndrome (PWS) is characterized by neonatal hypotonia and feeding problems in infancy, developmental delay, hyperphagia with obesity, short stature, hypogonadism, characteristic facial appearance, and behavior problems. The diagnosis of PWS is based on clinical findings that change with age. PWS has proved to be a difficult condition to recognize with the diagnosis often being delayed until later childhood or even adulthood. Therefore, a molecular testing for PWS is needed to confirm the diagnosis. OBJECTIVE: To study the clinical features of Prader-Willi syndrome patients and confirm diagnosis by molecular testing. MATERIAL AND METHOD: Eighteen Prader-Willi syndrome patients who were diagnosed between March, 1997 and February, 2002 at the Genetic Unit, Queen Sirikit National Institute of Child Health, Bangkok. Peripheral blood lymphocytes were obtained and cultured using the standard technique for chromosome analysis. For fluorescence in situ hybridization (FISH) studies, the specific DNA probes for loci small nuclear ribonucleoprotein polypeptide N (SNRPN) were used to detect deletion. Non-deleted cases were confirmed to have PWS by methylation analysis. RESULTS: The diagnosis of eighteen PWS patients was confirmed by FISH using DNA probes for loci SNRPN demonstrating a deletion of chromosome 15q11-q13 in fourteen cases (77%). Four cases (23%) were confirmed to have PWS resulting from maternal uniparental disomy by demonstrating exclusively maternal specific DNA methylation patterns. CONCLUSION: The clinical diagnosis of PWS should be confirmed by molecular testing especially in the infancy period to avoid needless invasive diagnostic testing.
Subject(s)
Child , Child, Preschool , Female , Genotype , Humans , In Situ Hybridization, Fluorescence , Infant, Newborn , Male , Prader-Willi Syndrome/diagnosis , Sequence Deletion/geneticsABSTRACT
La diabetes mellitus se ha convertido en una pandemia. En forma inusual se manifiesta asociada a condiciones con una causa genética establecida, que causan trastornos metabólicos específicos y que son dubdiagnosticadas y por lo tanto tratadas parcialmente o con el enfoque incorrecto. Una de ellas es el Síndrome de Prader Willi, una rara entidad causada por un trastorno genético puntual, con una incidencia anual de 1:10.000-16.000 nacidos vivos. Presentamos un caso de síndrome de Prader Willi estudiado por el Servicio de Medicina 2 del Hospital Vargas de Caracas, Venezuela
Subject(s)
Humans , Adult , Female , Diabetes Mellitus , Intellectual Disability , Obesity , Prader-Willi Syndrome/diagnosis , Medicine , VenezuelaABSTRACT
Seventy-two patients with clinical diagnoses of Prader-Willi (PWS; n = 28 patients) or Angelman syndromes (AS; n = 44 patients) were submitted to chromosome analysis, SNRPN-SNURF exon 1 methylation assay, and microsatellite genotyping. Analysis of the methylation pattern confirmed the PWS diagnosis in 18 out of 28 patients and the AS diagnosis in 20 out of 44 patients. FISH and microsatellite analysis detected a deletion in 30 patients (14 PWS and 16 AS). Eight patients had normal FISH results (4 PWS and 4 AS); microsatellite markers showed that these patients had a uniparental disomy (UPD). Based on this study, we propose a strategy for the routine diagnosis of these syndromes that consists of the following steps: 1) methylation analysis, which does not require parental samples; 2) microsatellite genotyping of patient and parents to differentiate deletions, UPD and imprinting mutations; and 3) FISH for otherwise uninformative cases, and whenever parental samples are not available. Of the 34 patients whose PWS or AS diagnoses were not confirmed by laboratory tests, five presented a small extra marker chromosome, identified in three of them as an inv dup(15). One AS patient carried a balanced t(15;15) translocation associated with paternal UPD. Therefore G-banded chromosome analysis should be performed on all such patients, to detect possible structural rearrangements
Subject(s)
Humans , Male , Female , Child , Adult , Angelman Syndrome/diagnosis , Prader-Willi Syndrome/diagnosis , Cytogenetic Analysis , In Situ Hybridization, Fluorescence , Angelman Syndrome/genetics , Prader-Willi Syndrome/geneticsABSTRACT
Background: The diagnosis of Prader-Willi and Angelman syndromes is difficult, since their phenotypic manifestations are variable and unspecific. The study of the methylation state of DNA in l5(q11-q13) using polymerase chain reaction, called methylation test, allows the diagnosis of most patients with Prader-Willi and Angelman syndromes, irrespective if the underlying molecular alteration is a deletion, uniparental disomy or a punctual imprinting mutation. Aim: To assess the effectiveness of methylation test in the diagnosis of Prader-Willi and Angelman syndromes. Patients and methods : Thirty seven cases with a presumptive diagnosis of Prader-Willi syndrome and 25 with the presumptive diagnosis of Angelman syndrome were studied. Methylation test was done in genomic DNA obtained from peripheral Iymphocytes. Results: Methylation test confirmed the clinical diagnosis in 11 of 37 patients with PraderWilli (30 percent) and 6 of 25 patients with Angelman syndrome (24 percent). Conclusions: Clinical criteria overestimate the diagnosis of Prader-Willi and Angelman syndromes. The initial diagnosis should be confirmed with the methylation test and, if necessary, with FISH that will detect most deletions in the region