Targeted massively parallel sequencing for congenital generalized lipodystrophy

ABSTRACT Objective: Our aim is to establish genetic diagnosis of congenital generalized lipodystrophy (CGL) using targeted massively parallel sequencing (MPS), also known as next-generation sequencing (NGS). Subjects and methods: Nine unrelated individuals with a clinical diagnosis of CGL were recruited. We used a customized panel to capture genes related to genetic lipodystrophies. DNA libraries were generated, sequenced using the Illumina MiSeq, and bioinformatics analysis was performed. Results: An accurate genetic diagnosis was stated for all nine patients. Four had pathogenic variants in AGPAT2 and three in BSCL2. Three large homozygous deletions in AGPAT2 were identified by copy-number variant analysis. Conclusions: Although we have found allelic variants in only 2 genes related to CGL, the panel was able to identify different variants including deletions that would have been missed by Sanger sequencing. We believe that MPS is a valuable tool for the genetic diagnosis of multi-genes related diseases, including CGL.

Lipodistrofias primarias: presentación clínica y diagnóstico / Clinical presentation and treatment of primary lipodystrophies

Lipodystrophies are a heterogeneous group of syndromes defined by a severe reduction of the adipose tissue. These can be congenital or acquired. Anatomically, they can be partial or generalized. The etiology of several lipodystrophies is well known. However, the cause of many others remains unknown. The commonest lipodystrophy worldwide is secondary to highly active anti-retroviral therapy in HIV-infected patients. By contrast, primary lipodystrophies (those not associated to any known disease or condition) are much less common and represent a diagnostic challenge. The major complications of lipodystrophies are metabolic, often resulting in severe insulin resistance, diabetes and dyslipidemia. No cure is available for lipodystrophies but the supplementation with recombinant leptin potently controls the metabolic abnormalities when there is a leptin deficiency. Herein, we review the clinical presentation, diagnostic process and therapeutic principles of the main primary lipodystrophy syndromes.

Inflammatory myopathy in the context of an unusual overlapping laminopathy

Summary Laminopathies are genetic disorders associated with alterations in nuclear envelope proteins, known as lamins. The LMNA gene encodes lamins A and C, and LMNA mutations have been linked to diseases involving fat (type 2 familial partial lipodystrophy [FPLD2]), muscle (type 2 Emery-Dreifuss muscular dystrophy [EDMD2], type 1B limb-girdle muscular dystrophy [LGMD1B], and dilated cardiomyopathy), nerves (type 2B1 Charcot-Marie-Tooth disease), and premature aging syndromes. Moreover, overlapping syndromes have been reported. This study aimed to determine the genetic basis of an overlapping syndrome in a patient with heart disease, myopathy, and features of lipodystrophy, combined with severe metabolic syndrome. We evaluated a 54-year-old woman with rheumatoid arthritis, chronic hypercortisolism (endogenous and exogenous), and a history of cured adrenal Cushing syndrome. The patient presented with a complex disorder, including metabolic syndrome associated with mild partial lipodystrophy (Köbberling-like); mild hypertrophic cardiomyopathy, with Wolff-Parkinson- White syndrome and atrial fibrillation; and limb-girdle inflammatory myopathy. Mutational analysis of the LMNA gene showed a heterozygous c.1634G>A (p.R545H) variant in exon 10 of LMNA. This variant has previously been independently associated with FPLD2, EDMD2, LGMD1B, and heart disease. We describe a new, LMNA-associated, complex overlapping syndrome in which fat, muscle, and cardiac disturbances are related to a p.R545H variant.

Atypical generalized lipoatrophy and severe insulin resistance due to a heterozygous LMNA p. T10I mutation / Lipoatrofia generalizada atípica e resistência insulínica grave devido à mutação p. T10I em heterozigose no gene LMNA

Lipodystrophies are a group of heterogeneous disorders characterized by the loss of adipose tissue and metabolic complications. The main familial forms of lipodystrophy are Congenital Generalized Lipodystrophy and Familial Partial Lipodystrophy (FPLD). FPLD may result from mutations in the LMNA gene. Besides FPLD, mutations in LMNA have been shown to be responsible for other inherited diseases called laminopathies. Here we describe the case of a 15-year-old girl who was referred to our service due to diabetes mellitus and severe hypertriglyceridemia. Physical examination revealed generalized loss of subcutaneous fat, confirmed by DEXA (total body fat 8.6 percent). As the patient presented with pubertal-onset of generalized lipodystrophy and insulin resistance, molecular analysis of the LMNA gene was performed. We identified a heterozygous substitution in exon 1 (c.29C>T) predicting a p.T10I mutation. In summary, we describe an atypical phenotype of lipodistrophy associated with a de novo appearance of the p.T10I mutation in LMNA gene.

As lipodistrofias são um grupo heterogêneo de doenças caracterizadas por perda de tecido adiposo e complicações metabólicas. As formas hereditárias mais importantes de lipodistrofias são: lipodistrofia congênita generalizada e lipodistrofia parcial familiar (LDPF). LDPF resulta de mutações no gene LMNA que codificam as lâminas tipo A. Além da LDPF, mutações no gene LMNA são responsáveis por outras doenças hereditárias, denominadas laminopatias. Descrevemos o caso de uma paciente de 15 anos de idade encaminhada por diabetes melito e hipertrigliceridemia grave. Ao exame físico, apresentava perda generalizada de gordura subcutânea que foi confirmada por DEXA (gordura corporal total 8,6 por cento). Como a paciente apresentava perda de gordura de início na puberdade e resistência insulínica, foi realizada análise molecular do gene LMNA. Identificamos uma substituição em heterozigose no éxon 1 (c.29C>T), resultando na mutação p.T10I. Em sumário, um caso de fenótipo atípico de lipodistrofia generalizada devido à mutação de novo p.T10I no gene LMNA é descrito.

Uncommon allele in APO AI-CIII-AIV gene cluster in a family with congenital generalized lipodystrophy

Congenital generalized lipodystrophy is a rare inherited disease. One of its features is a disturbance in lipid metabolism characterized by hypercholesterolemia and hypertriglyceridemia. A brother and a sister with congenital generalized lipodystrophy, an 8-year old male and a 12-year old female were studied. The mother and a 6-year old brother were healthy. The genetic analysis of Sstl RFLP of the apo Al-CIII-AIV gene cluster showed the presence of the rare Sstl allele (S2) in the patients but not in the healthy mother and brother. As this uncommon allele has been reported to be related to high plasma triglyceride levels, this association could be relevant in explaining in part the hypertriglyceridemia observed in these patients.

Congenital generalized lipodystrophy, a case report.

Generalized lipodystrophy is a rare condition which can be divided into congenital and acquired types, based on the age at presentation and pattern of inheritance. The congenital type of generalized lipodystrophy or Lawrence-Seip syndrome presents in first two years of life and is inherited in an autosomal recessive pattern. The diagnosis is made on the basis of loss of body fat, muscular hypertrophy, acanthosis nigricans, hirsutism, hepatomegaly with fatty liver, hyperlipidemia and hyperglycemia with insulin resistance. A 2 1/2-year-old Thai girl with the clinical features of Lawrence-Seip syndrome is reported. Abnormal platelet function was detected in this girl.

Sindrome de Lipodistrofia Congénita Generalizada / Congenital generalized lipodystrophy syndrome

El actual estudio trata sobre la forma de presentación y evolución de los pacientes con lipodistrofia congénita generalizada o el Síndrome de Seip-Berardinelli. Se caracteriza por la ausencia de tejido graso subcutáneo, cirrosis hepática, desarrollo de diabetes resistente a la insulina, hiperlipemia, y crecimiento corporal rápido con edad ósea avanzada en la infancia, coexistiendo alteraciones cutáneas, desarrollo muscular exagerado y compromiso de otros órganos. Se presentan 3 casos de esta patología diagnosticados entre 9 y 19 meses de edad. Las 3 pacientes presentaban varias características en común: aparentaban una edad mayor a la cronlógica, cara triangular, abundante cabello, lesiones hiperpigmentadas a predominio de pliegues, marcada disminución de tejido celular subcutáneo, prominencia muscular y hepatomegalia. Otros hallazgos clínicos sólo se demostraron en una u otra de las pacientes. La evaluación de laboratorio muestra alteración precoz de lípidos a predominio de triglicéridos, conservando la glicemia y la curva de tolerancia a la glucosa dentro de límites normales. Edad ósea avanzada en 1 de los 3 casos. Analizando los datos de las pacientes y de la literatura respecto a la fisiopatología y posibles efectos beneficiosos de los neurolépticos, se sugiere existencia de alguna anomalía a nivel del hipotálamo y/o hipófisis responsable de la presentacióm del cuadro clínico.

Síndrome de Donohue (leprechaunismo) / Donohue's syndrome

Se presenta el caso de una niña de 5 meses, con un fenotipo compatible con síndrome de Donohue; confirmándose el diagnóstico en la anatomía patológica por la presencia de transformación quística de los corpúsculos de Hassall en el timo, abundante pigmento de fierro en el hígado e hiperplasia de los islotes de Langerhans y aumento de células Beta en el páncreas. Se revisa la literatura y se discuten los posibles mecanismos patogénicos involucrados

Una enfermedad de base genética: lipodistrofia congénita generalizada; presentación de un caso / A genetical based disease: congenital generalized lipodystrophy; report of a case

Se presenta el caso de un niño de 13 meses de edad con antecedentes de sepsis urinaria, anorexia severa y pérdida de peso desde los 4 meses de edad. Al examen físico se observa una facie simiesca con pérdida del panículo adiposo, hipertricosis generalizada, relieve muscular visible, ausencia del tejido celular subcutáneo, prominencia de la red venosa en miembros superiores e inferiores, manos y pies grandes, así como hipertrofia del pene. Se comprueba implantación baja de las orejas. Con estos elementos clínicos se sospecha que padezca de una lipodistrofia congénita generalizada, se le realiza biopsia muscular y se encuentra ausencia total de tejido adiposo, lo cual ayuda a confirmar el diagnóstico. Se detectan, también, alteraciones de los niveles lipídicos en sangre, no así en la glicemia. Se presenta este caso como una entidad de base genética, que se trasmite con carácter autosómico recesivo, pero de causa no totalmente esclarecida todavía. Se discuten algunos posibles mecanismos etiológicos así como terapéuticos. Consideramos que se debe profundizar más en estos aspectos para evitar complicaciones habituales, como la diabetes mellitus y los trastornos hepáticos