Mutations In BSCL2 Gene Research Articles

The neonatal onset diabetes mellitus of Chinese neonate with congenital generalized lipodystrophy 2: a case report

BackgroundCongenital generalized lipodystrophy (CGL) is a clinically heterogeneous disorder characterized by near total absence of adipose tissue along with metabolic complications. Diabetes mellitus developed from CGL usually present between ages 15 and 20 years, and there are few reports in neonate.Case presentationIn this report, we described a rare clinical presentation of CGL in a 12-day-old Chinese female neonates with hyperglycemia, hyperlipidemia, and subsequently appeared diabetes, hepatomegaly and fatty liver. The two clinical-exome sequencing identified heterozygous null mutations (c.793C > T and c.565G > T) in BSCL2 gene which was inherited from father and mother respectively. To date, it was the firstly reported CGL patient with neonatal onset diabetes. The neonate was treated with antibiotic, insulin and deeply hydrolyzed formula milk to significantly decrease FBG and serum trigylcerides levels. ConclusionsOur case report analyzes the causes of early onset diabetes may relate with the locus of BSCL2 gene mutations and infection induction. It also suggests the importance of early identification, genetic analysis, and symptomatic treatment in the CGL, which are essential for improving the prognosis of children.

SARS-COV-2 infection outcomes in patients with congenital generalized lipodystrophy

BackgroundA new strain of human coronavirus (HCoV) spread rapidly around the world. Diabetes and obesity are associated with a worse prognosis in these patients. Congenital Generalized Lipodystrophy (CGL) patients generally have poorly controlled diabetes and require extremely high doses of insulin. There is no documentation in the literature of cases of COVID in CGL patients. Thus, we aimed to evaluate the prevalence of SARS-CoV-2 infection in CGL patients, and the association of their clinical and metabolic characteristics and outcomes.MethodsThis is a cross-sectional study carried out between July and October 2020. Clinical data collected were respiratory or other flu-like symptoms, need of hospitalization in the last three months, CGL comorbidities, and medications in use. Cholesterol, triglycerides, glycohemoglobin A1c levels, anti-SARS-CoV-2 antibodies and nasopharyngeal swab for RT-qPCR were also obtained in all CGL patients. Mann-Whitney U test was used to analyze the characteristics of the participants, verifying the non-adherence of the data to the Gaussian distribution. In investigating the association between categorical variables, we used Pearson's chi-square test and Fisher's exact test. A significance level of 5% was adopted.ResultsTwenty-two CGL patients were assessed. Eight subjects (36.4%) had reactive anti-SARS-CoV-2 antibodies. Only one of these, also presented detectable RT-qPCR. Five individuals (62.5%) were women, median age of 13.5 years (1 to 37). Symptoms like fever, malaise, nausea, diarrhea and chest pain were present, and all asymptomatic patients were children. All subjects had inadequate metabolic control, with no difference between groups. Among positive individuals there was no difference between those with AGPAT2 (75%) and BSCL2 gene mutations (25%) (p > 0.05). No patient needed hospitalization or died.ConclusionsWe described a high prevalence of SARS-CoV-2 infection in CGL patients with a good outcome in all of them. These findings suggest that at least young CGL patients infected by SARS-COV-2 are not at higher risk of poor outcome, despite known severe metabolic comorbidities.

Leu124Serfs*26, a novel AGPAT2 mutation in congenital generalized lipodystrophy with early cardiovascular complications

BackgroundCongenital generalized lipodystrophy (CGL) is a rare autosomal recessive disorder characterized by the near-total loss of subcutaneous adipose tissue soon after birth, resulting in ectopic fat deposition and severe metabolic disturbances. Most cases are caused by AGPAT2 or BSCL2 gene mutations. We aimed to report two unrelated CGL patients with a novel frameshift mutation in AGPAT2 (p.Leu124Serfs*26).MethodsClinical features and laboratory were obtained by medical interview and medical records review. DNA was extracted, amplified and sequenced. Mutation Taster was used to estimate the potential biological impact of the AGPAT2 mutations on the protein function.ResultsPatient 1: a 30-year-old woman with lipodystrophy phenotype at birth and diagnosis of diabetes at age 13 presented with severe hypertriglyceridemia and pancreatitis at age 17, hypertension and albuminuria at age 18, proliferative diabetic retinopathy with visual loss at age 25, and an acute myocardial infarction due to multivessel coronary disease during a hospitalization for forefoot amputation at age 29. At this time, she required hemodialysis due to end-stage renal disease. Patient 2: a 12-year-old girl with lipodystrophy phenotype and hypertriglyceridemia detected in the first year of life and abnormalities in the global longitudinal strain, evaluated by speckle-tracking echocardiography last year. Molecular analysis identified a c.369_372delGCTC (p.Leu124Serfs*26) AGPAT2 mutation in both unrelated patients, a compound heterozygous mutation in Patient 1, and homozygous mutation in Patient 2.ConclusionWe describe two unrelated patients with type 1 CGL due to Leu124Serfs*26, a novel AGPAT2 frameshift mutation, presenting as early cardiovascular disease. These findings suggest an association between Leu124Serfs*26 and a more aggressive phenotype.

Targeting ATGL to rescue BSCL2 lipodystrophy and its associated cardiomyopathy.

Mutations in BSCL2 gene underlie human type 2 Berardinelli-Seip Congenital Lipodystrophy (BSCL2) disease. Global Bscl2-/- mice recapitulate human BSCL2 lipodystrophy and develop insulin resistance and hypertrophic cardiomyopathy. The pathological mechanisms underlying the development of lipodystrophy and cardiomyopathy in BSCL2 are controversial. Here we report that Bscl2-/- mice develop cardiac hypertrophy due to increased basal IGF1 receptor (IGF1R)-mediated PI3K/AKT signaling. Bscl2-/- hearts exhibited increased adipose triglyceride lipase (ATGL) protein stability and expression causing drastic reduction of glycerolipids. Excessive fatty acid oxidation was overt in Bscl2-/- hearts, partially attributing to the hyperacetylation of cardiac mitochondrial proteins. Intriguingly, pharmacological inhibition or genetic inactivation of ATGL could rescue adipocyte differentiation and lipodystrophy in Bscl2-/- cells and mice. Restoring a small portion of fat mass by ATGL partial deletion in Bscl2-/- mice not only reversed the systemic insulin resistance, but also ameliorated cardiac protein hyperacetylation, normalized cardiac substrate metabolism and improved contractile function. Collectively, our study uncovers novel pathways underlying lipodystrophy-induced cardiac hypertrophy and metabolic remodeling and pinpoints ATGL as a downstream target of BSCL2 in regulating the development of lipodystrophy and its associated cardiomyopathy.

Progressive Myoclonus Epilepsy in Congenital Generalized Lipodystrophy type 2: Report of 3 cases and literature review

PurposeA small case series with a neurodegenerative disorder involving central nervous system and related to Seipin mutations was recently reported. Herein we describe clinical and EEG features of three patients presenting with Progressive Myoclonus Epilepsy (PME) and Congenital Generalized Lipodystrophy type 2 (CGL2) related to novel Seipin mutations. MethodsThe EEG-clinical picture was evaluated at epilepsy onset and in the follow-up period. The molecular analysis of BSCL2, Laforin and Malin genes was performed to patients and/or their parents by Denaturing High Performance Liquid Chromatography and automated nucleotide sequencing. Skin specimens collected from a patient were processed for histochemical and ultrastructural analysis. ResultsThe CGL2-PME syndrome co-segregated with two different BSCL2 genotypes: the homozygosity for c.782_783dupG involving exon 8 (two cases), or the compound heterozygosity for c.782_783dupG/c.828_829delAA (one case). Periodic-Acid Schiff positive osmiophilic material in the cytoplasm of fibrocytes and eccrine-gland cells were found in skin specimens. The lack of Lafora’s bodies in skin specimens and the molecular analysis excluding mutations in Laforin and Malin genes ruled out Lafora disease. ConclusionThe spectrum of CGL2 associated to BSCL2 gene mutations may include PMEs. Selected mutations in BSCL2 gene seem to be related to PMEs in patients with CGL2 phenotype.

AB143. Berardinelli-Seip congenital lipodystrophy and its diagnostic implications

Berardinelli-Seip congenital lipodystrophy (BSCLD) (OMIM#269700) is a rare autosomal recessive disorder characterized by marked paucity of adipose tissue, a muscular habitus, insulin resistance, hypertriglyceridemia and hepatic steatosis. It is an anabolic syndrome due to the deficiency of leptin, a lipid modulator, leading to the inappropriate mobilization of fat. Four types of BSCLD have been described based on the site of genetic mutation. Type 2 accounts for an earlier onset, more severe complications and intellectual disability. This is due to the lower leptin levels and the loss of functional seipin in type 2 BSCLD. We report the evolving phenotype of type 2 BSCLD in a boy clinically diagnosed at age 5 months and confirmed by molecular genetic study which revealed a pathogenic mutation in the BSCL2 gene: c.782dupG, p.lle262Hisfs*12homozygous. He is the firstborn of non-consanguineous parents with no significant family history. He has a muscular habitus with a distinct facies, hypertrichosis, absence of subcutaneous fat and hepatomegaly. Investigations revealed hypertriglyceridemia and insulin resistance. A conventional approach to management with dietary fat restriction successfully controlled his biochemical parameters, thus preventing catastrophic complications such as systemic arterial hypertension, heart failure and pancreatitis. Genetic counseling was conferred and prenatal testing recommended for future pregnancies. On follow-up, he had a muscular habitus with hepatomegaly and global developmental delay. Despite early correction of his biochemical parameters, an abdominal ultrasound revealed early onset fatty liver disease and an echocardiogram showed a thickened interventricular septum suggestive of early hypertrophic obstructive cardiomyopathy (HOCM). A fasting serum leptin done was low at 0.8 ng/mL (normal range, 2.0-5.6 ng/mL) confirming leptin deficiency. A leptin analog is now available as an adjunct to mollify the metabolic complications of BSCLD. However, it is yet to be available in developing nations and whether it is able to assuage progressive hepatic cholestasis and HOCM remains a field to venture. This report highlights the importance of early recognition and confirmation by molecular diagnosis to direct appropriate surveillance of complications. This also enables early genetic counseling and prenatal testing for future pregnancies. We describe the evolving phenotype, pertinent investigations and the conventional approach to the management of BSCLD.

Deletion mutation in BSCL2 gene underlies congenital generalized lipodystrophy in a Pakistani family

BackgroundCongenital generalized lipodystrophy (CGL) also known as Berardinelli-Seip Congenital Lipodystrophy (BSCL) is a genetically heterogeneous disorder characterized by loss of adipose tissues, Acanthosis nigricans, diabetes mellitus, muscular hypertrophy, hepatomegaly and hypertriglyceridemia. There are four subclinical phenotypes of CGL (CGL1-4) and mutations in four genes AGPAT2, BSCL2, CAV1 and PTRF have been assigned to each type.MethodsThe study included clinical and molecular investigations of CGL disease in a consanguineous Pakistani family. For mutation screening all the coding exons including splice junctions of AGPAT2, BSCL2, CAV1 and PTRF genes were PCR amplified and sequenced directly using an automated DNA sequencer ABI3730.ResultsSequence analysis revealed a single base pair deletion mutation (c.636delC; p.Tyr213ThrfsX20) in exon 5 of BSCL2 gene causing a frame shift and premature termination codon.ConclusionMutation identified here in BSCL2 gene causing congenital generalized lipodystrophy is the first report in Pakistani population. The patients exhibited characteristic features of generalized lipodystrophy, Acanthosis nigricans, diabetes mellitus and hypertrophic cardiomyopathy.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1913913076864247.

Course of Atypical Manifestations of a Case of Charcot-Marie-Tooth Disease over 35 Years of Clinical Observation

Introduction: Atypical manifestations of peripheral neuropathy are not rare, challenging the differential diagnosis. In the past, the diagnosis of hereditary neuropathy was mainly based on the clinical and electromyographic (EMG) findings and, occasionally, biopsy. Nowadays, the genetic tests allow us to identify more than 40 different genes/loci associated with Charcot-Marie-Tooth (CMT) disease, although some subtypes are clinically indistinguishable. We have followed a patient with a clinical diagnosis of apparent sporadic and atypical CMT and recently diagnosed genetically as distal hereditary motor neuropathy, type V (dHMN-V). Case Report: Thirty-five years ago, a 16 years old patient complained muscular weakness and wasting at the hands small muscles. Sporadic fasciculations were observed whereas deep tendon reflexes and sensation were normal. EMG examination revealed neurogenic muscular denervation in the distribution of C7, C8 and T1 segments bilaterally. Muscular biopsy of the left Biceps Brachii showed rare atrophic fibers and some cellular atypia. The disease has undergone a clinical and EMG progression and diffusion over the years, involving the lower limbs and leading to a bilateral steppage. A more slight diffuse axonal motor neuropathy was also identified in the proband’s son and second cousin. The genetic study found a known missense mutation in BSCL2 gene related to a dHMN-V. Interestingly, there was a remarkable intra-familiar phenotypic variability, especially in the clinical onset and severity. Discussion: Atypical manifestations of hereditary neuropathies often overlap with other conditions. The present case highlights how a comprehensive clinical evaluation and a careful follow-up have led to a correct diagnosis even 35 years later and have allowed to identify other affected family members. The apparent lack of familiarity was probably due to the very soft presentation in the proband’s relatives. Although the genetic study was not available at that time, the first clinical diagnosis was not disavowed. The main differential diagnoses and a brief review of similar reported cases are discussed.

Novel mutations of the BSCL2 and AGPAT2 genes in 10 families with Berardinelli–Seip congenital generalized lipodystrophy syndrome

Congenital generalized lipodystrophy, or Berardinelli-Seip syndrome, is a rare autosomal recessive disease caused by mutations in either the BSCL2 or AGPAT2 genes. This syndrome is characterized by an almost complete loss of adipose tissue usually diagnosed at birth or early infancy resulting in apparent muscle hypertrophy. Common clinical features are acanthosis nigricans, hepatomegaly with or without splenomegaly and high stature. Acromegaloid features, cardiomyopathy and mental retardation can also be present. We investigated 11 kindreds from different geographical areas of Brazil (northeast and southeast). All coding regions as well as flanking intronic regions of both genes were examined. Polymerase chain reaction (PCR) amplifications were performed using primers described previously and PCR products were sequenced directly. Four AGPAT2 and two BSCL2 families harboured the same set of mutations. BSCL2 gene mutations were found in the homozygous form in four kindreds (c.412C>T c.464T>C, c.518-519insA, IVS5-2A>G), and in two kindreds compound mutations were found (c.1363C>T, c.424A>G). In the other four families, one mutation of the AGPAT2 gene was found (IVS3-1G>C and c.299G>A). We have demonstrated four novel mutations of the BSCL2 and AGPAT2 genes responsible for Berardinelli-Seip syndrome and Brunzell syndrome (AGPAT2-related syndrome).

The first Italian family with evidence of pyramidal impairment as phenotypic manifestation of Silver syndrome BSCL2 gene mutation

Silver syndrome (SPG17) is a rare form of hereditary spastic paraparesis. Its relationship to distal hereditary motor neuropathy (dHMN) type V is underlined by the recent discovery of causative mutation in BSCL2 gene coding for a protein termed seipin, an integral membrane protein of endoplasmic reticulum, with unknown function. Here we report the third Italian family with dHMN and SPG17 in which two affected members harbor the heterozygous N88S mutation in the BSCL2 gene. The proband developed a severe paraparetic spastic gait, while, in the other Italian families reported so far, no signs of upper motor neuron involvement were observed. This family confirms the clinical heterogeneity associated with this specific mutation. Moreover, this is the first report in which neuroimaging seems to confirm the pyramidal alterations in dHMN associated to SPG17.