A rare co-occurrence of duchenne muscular dystrophy, congenital adrenal hypoplasia and glycerol kinase deficiency due to Xp21 contiguous gene deletion syndrome: case report.

BACKGROUND: Contiguous gene deletion syndromes are rare genomic disorders caused by deletion of large segments of DNA resulting in co-occurrence of apparently unrelated multiple clinical phenotypes. We report a boy with contiguous gene deletion involving Xp21 genomic location. CASE PRESENTATION: A Sri Lankan boy with developmental delay and failure to thrive first presented at three years of age with hypovolaemia, hyperpigmentation and drowsiness. Investigations done at that time revealed hypoglycaemia, hyponatraemia, hyperkalaemia, low cortisol, low aldosterone, high ACTH and low 17-hydroxyprogesterone. He was diagnosed to have primary adrenal insufficiency. During follow-up at five years, he was noted to have progressive difficulty in walking, waddling gait, hypotonia, calf hypertrophy and positive Gower's sign. His creatine kinase was very high, and the electromyogram showed myopathy. Genetic analysis revealed hemizygous deletion involving the final 35 exons of the dystrophin gene confirming the diagnosis of Duchenne muscular dystrophy. Further investigations revealed pseudohypertriglyceridemia, large glycerol peak on urine organic acid analysis and hemizygous deletion of the glycerol kinase gene confirming glycerol kinase deficiency. Based on the presence of Duchenne muscular dystrophy, glycerol kinase deficiency and probable congenital adrenal hypoplasia along with genetic confirmation of deletions involving dystrophin and glycerol kinase genes, the diagnosis of Xp21 contiguous gene deletion syndrome was made. CONCLUSIONS: We report a child with contiguous gene deletion syndrome who was initially diagnosed as having isolated primary adrenal insufficiency probably due to congenital adrenal hypoplasia. Later he was confirmed to have Duchenne muscular dystrophy and glycerol kinase deficiency, as well. This case report highlights the importance of pre-emptive evaluation and identification of genetic defects when patients present with seemingly unrelated diseases that could aid in accurate diagnoses of contiguous gene deletion syndromes.

[Glycerol kinase deficiency: a metabolic cause of global developmental delay]. / Deficiencia de glicerolcinasa: una causa metabolica de retraso global del desarrollo.

TITLE: Deficiencia de glicerolcinasa: una causa metabolica de retraso global del desarrollo.

Deficiencia de glicerolcinasa: una causa metabólica de retraso global del desarrollo / Glycerol kinase deficiency: a metabolic cause of global developmental delay

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[Glycerol kinase deficiency in adult patient: hypertriglyceridemia resistance to diet and pharmacological treatment]. / Déficit de glicerol kinasa en el adulto: hipertrigliceridemia resistente a tratamiento dietético y farmacológico.

CASE REPORT: we present an 85-year-old patient with polydipsia, polyuria and severe hypertriglyceridemia of 27 years of evolution, without pancreatitis, resistant to dietary and pharmacological treatments. He was diagnosed of hyperglycerolemia due to glycerol kinase deficiency (GKD) based on: transparent non-lipemic serum, with glycerol increase in plasma and urine, without glycerol 3 phosphate increase, and a deletion, not previously described, in the glycerol kinase gene. DISCUSSION: a correct dietary treatment with frequent meals and rich in complex carbohydrates, without medication, improved the symptomatology.

Caso clínico: presentamos un paciente varón de 85 años con polidipsia, poliuria e hipertrigliceridemia severa de 27 años de evolución, sin pancreatitis, persistente y resistente a tratamientos dietético y farmacológico. Se diagnosticó de hiperglicerolemia por déficit de glicerol kinasa (GKD) en base a: suero transparente no lipémico, aumento de glicerol en plasma y orina, sin aumento de glicerol 3 fosfato y deleción, no descrita previamente, en el gen de la glicerol kinasa.Discusión: un tratamiento dietético correcto con comidas frecuentes y rico en carbohidratos complejos, sin medicación, mejoró la sintomatología.

Déficit de glicerol kinasa en el adulto: hipertrigliceridemia resistente a tratamiento dietético y farmacológico / Glycerol kinase deficiency in adult patient: hypertriglyceridemia resistance to diet and pharmacological treatment

Caso clínico: presentamos un paciente varón de 85 años con polidipsia, poliuria e hipertrigliceridemia severa de 27 años de evolución, sin pancreatitis, persistente y resistente a tratamientos dietético y farmacológico. Se diagnosticó de hiperglicerolemia por déficit de glicerol kinasa (GKD) en base a: suero transparente no lipémico, aumento de glicerol en plasma y orina, sin aumento de glicerol 3 fosfato y deleción, no descrita previamente, en el gen de la glicerol kinasa. Discusión: un tratamiento dietético correcto con comidas frecuentes y rico en carbohidratos complejos, sin medicación, mejoró la sintomatología

Case report: we present an 85-year-old patient with polydipsia, polyuria and severe hypertriglyceridemia of 27 years of evolution, without pancreatitis, resistant to dietary and pharmacological treatments. He was diagnosed of hyperglycerolemia due to glycerol kinase defi ciency (GKD) based on: transparent non-lipemic serum, with glycerol increase in plasma and urine, without glycerol 3 phosphate increase, and a deletion, not previously described, in the glycerol kinase gene. Discussion: a correct dietary treatment with frequent meals and rich in complex carbohydrates, without medication, improved the symptomatology

Recém-nascido com deficiência de glicerol quinase: um caso clínico / Neonate with glycerol kinase deficiency: A clinical case

OBJETIVOS: Relatar o caso de um recém-nascido com deficiência de glicerol quinase, no qual foi identificada uma mutação isolada ainda não descrita no gene GK. DESCRIÇÃO DO CASO: Um recém-nascido com 10 dias de vida foi trazido ao serviço de urgência por recusa alimentar com 24 horas de evolução. Ao exame físico apresentava perda de 31% do peso de nascimento e sinais de desidratação. Os exames laboratoriais constataram presença de acidose metabólica com anion gap aumentado, creatinina 2,41mg/dL, ureia 306 mg/dL, hipernatremia (182mEq/L), hipercalemia (6,8mEq/L), hipercloremia (151mEq/L), transaminase glutâmico-oxalacética 879U/L, transaminase glutâmico-pirúvica 243U/L, triglicerídeos 725mg/dL. A cromotagrafia de ácidos orgânicos revelou hiperglicerolemia e glicerolúria compatíveis com deficiência de glicerol quinase. O estudo genético revelou uma mutação ainda não descrita: c.187T>C (p.S63P) em hemizigotia no gene GK. CONCLUSÕES: A causa mais frequente de desidratação hipernatrêmica no período neonatal é a hipogalatia materna. Nos casos mais graves de desidratação outras etiologias devem ser consideradas, incluindo causas metabólicas como a deficiência de glicerol quinase. Neste caso foi encontrada uma mutação no gene GK ainda não descrita.

AIMS: To report the case of a newborn with glycerol kinase deficiency, in which an isolated mutation not yet described in the GK gene was identified. CASE DESCRIPTION: A neonate with 10 days of age was brought to the emergency department for refusal to feed with 24 hours of evolution. Physical examination showed a loss of 31% of birth weight and signs of dehydration. Laboratory tests revealed a metabolic acidosis with increased anion gap, creatinine 2.41mg/dL, urea 306mg/dL, hypernatremia (182mEq/L), hyperkalemia (6.8mEq/L), hyperchloremia (151mEq/L), glutamic-oxalacetic transaminase 879U/L, glutamic-pyruvic transaminase 243U/L, triglycerides 725mg/dL. Chromotagraphy of organic acids revealed hyperglycerolemia and glyceroluria compatible with glycerol kinase deficiency. The genetic study revealed a mutation not yet described: c.187T>C (p.S63P) as hemizygote status in the GK gene. CONCLUSIONS: The most frequent cause of hypernatremic dehydration in the neonatal period is maternal hypogalactia. In more severe cases of dehydration, other etiologies should be considered, including metabolic causes such as glycerol kinase deficiency. In this case a mutation not yet described in the GK gene was found.

Cholestasis and Hepatic Iron Deposition in an Infant With Complex Glycerol Kinase Deficiency.

We present a 6-week-old male infant with persistent hyperbilirubinemia, hypertriglyceridemia, elevated creatine kinase levels, and transaminitis since the second week of life. When he developed hyperkalemia, clinical suspicion was raised for adrenal insufficiency despite hemodynamic stability. A full endocrine workup revealed nearly absent adrenocorticotropic hormone. Coupled with his persistent hypertriglyceridemia (peak of 811 mg/dL) and elevated creatine kinase levels (>20 000 U/L), his corticotropin level lead to a clinical diagnosis of complex glycerol kinase deficiency (GKD), also known as Xp21 deletion syndrome. This complex disorder encompasses the phenotype of Duchenne muscular dystrophy, GKD, and congenital adrenal hypoplasia due to the deletion of 3 contiguous genetic loci on the X chromosome. Our case exemplifies the presentation of this disorder and highlights the important lesson of distinguishing between adrenal hypoplasia congenita and congenital adrenal hyperplasia, as well as the sometimes subtle presentation of adrenal insufficiency. To our knowledge, it is also the first reported case of complex GKD deficiency with the additional finding of hepatic iron deposition, which may indicate a potential area for exploration regarding the pathogenesis of liver injury and cholestasis seen in cortisol-related endocrinopathies.

Modifier genes: Moving from pathogenesis to therapy.

This commentary will focus on how we can use our knowledge about the complexity of human disease and its pathogenesis to identify novel approaches to therapy. We know that even for single gene Mendelian disorders, patients with identical mutations often have different presentations and outcomes. This lack of genotype-phenotype correlation led us and others to examine the roles of modifier genes in the context of biological networks. These investigations have utilized vertebrate and invertebrate model organisms. Since one of the goals of research on modifier genes and networks is to identify novel therapeutic targets, the challenges to patient access and compliance because of the high costs of medications for rare genetic diseases must be recognized. A recent article explored protective modifiers, including plastin 3 (PLS3) and coronin 1C (CORO1C), in spinal muscular atrophy (SMA). SMA is an autosomal recessive deficit of survival motor neuron protein (SMN) caused by mutations in SMN1. However, the severity of SMA is determined primarily by the number of SMN2 copies, and this results in significant phenotypic variability. PLS3 was upregulated in siblings who were asymptomatic compared with those who had SMA2 or SMA3, but identical homozygous SMN1 deletions and equal numbers of SMN2 copies. CORO1C was identified by interrogation of the PLS3 interactome. Overexpression of these proteins rescued endocytosis in SMA models. In addition, antisense RNA for upregulation of SMN2 protein expression is being developed as another way of modifying the SMA phenotype. These investigations suggest the practical application of protective modifiers to rescue SMA phenotypes. Other examples of the potential therapeutic value of novel protective modifiers will be discussed, including in Duchenne muscular dystrophy and glycerol kinase deficiency. This work shows that while we live in an exciting era of genomic sequencing, a functional understanding of biology, the impact of its disruption, and possibilities for its repair have never been more important as we search for new therapies.

Rice endosperm protein slows progression of fatty liver and diabetic nephropathy in Zucker diabetic fatty rats.

We previously reported that rice endosperm protein (REP) has renoprotective effects in Goto-Kakizaki rats, a non-obese diabetic model. However, whether these effects occur in obese diabetes remains unclear. This study aimed to clarify the effects of REP on obese diabetes, especially on fatty liver and diabetic nephropathy, using the obese diabetic model Zucker diabetic fatty (ZDF) rats. In total, 7-week-old male ZDF rats were fed diets containing 20 % REP or casein (C) for 8 weeks. Changes in fasting blood glucose levels and urinary markers were monitored during the experimental period. Hepatic lipids and metabolites were measured and renal glomeruli were observed morphologically. HbA1c levels were significantly lower in rats fed REP, compared with C (P<0·05). Compared with C in the liver, REP prevented lipid accumulation (total lipid, TAG and total cholesterol, P<0·01). Liver metabolome analysis indicated that levels of metabolites associated with glycolysis, the pentose phosphate pathway and carnitine metabolism were significantly greater in the REP group than in the C group (P<0·05), suggesting activation of both glucose catabolism and fatty acid oxidation. The metabolite increases promoted by REP may contribute to suppression of liver lipid accumulation. Urinary excretion of albumin and N-acetyl-ß-d-glucosaminidase was significantly reduced in rats fed REP for 8 weeks (P<0·01). In addition, there was a distinct suppression of mesangial matrix expansion and glomerular hypertrophy in response to REP (P<0·01). Thus, REP had preventive effects on obese diabetes, fatty liver and diabetic nephropathy.

Endocrine Dysfunctions in Patients with Inherited Metabolic Diseases.

OBJECTIVE: Inherited metabolic diseases (IMDs) can affect many organ systems, including the endocrine system. There are limited data regarding endocrine dysfunctions related to IMDs in adults, however, no data exist in pediatric patients with IMDs. The aim of this study was to investigate endocrine dysfunctions in patients with IMDs by assessing their demographic, clinical, and laboratory data. METHODS: Data were obtained retrospectively from the medical reports of patients with IMDs who were followed by the division of pediatric metabolism and nutrition between June 2011 and November 2013. RESULTS: In total, 260 patients [139 males (53%) and 121 females (47%)] with an IMD diagnosis were included in the study. The mean age of the patients was 5.94 (range; 0.08 to 49) years and 95.8% (249 of 260 patients) were in the pediatric age group. Growth status was evaluated in 258 patients and of them, 27 (10.5%) had growth failure, all cases of which were attributed to non-endocrine reasons. There was a significant correlation between growth failure and serum albumin levels below 3.5 g/dL (p=0.002). Only three of 260 (1.1%) patients had endocrine dysfunction. Of these, one with lecithin-cholesterol acyltransferase deficiency and another with Kearns-Sayre syndrome had diabetes, and one with glycerol kinase deficiency had glucocorticoid deficiency. CONCLUSION: Endocrine dysfunction in patients with IMDs is relatively rare. For this reason, there is no need to conduct routine endocrine evaluations in most patients with IMDs unless a careful and detailed history and a physical examination point to an endocrine dysfunction.

Complex Glycerol Kinase Deficiency and Adrenocortical Insufficiency in Two Neonates.

Contiguous gene deletions of chromosome Xp21 can lead to glycerol kinase deficiency and severe adrenocortical insufficiency (AI) in a male newborn among other problems. We describe our experience with two such patients who presented with dysmorphic facies, AI, and pseudo-hypertriglyceridemia. Both infants had normal serum 17-hidroxyprogesterone levels, and adrenal glands could not be observed with ultrasonography. Creatine kinase and triglyceride levels were measured to elucidate the etiology of adrenal hypoplasia and were above normal limits in both cases. Both patients required steroid and salt supplementation. They were both found to have Xp21.2 deletions (DMD, NR0B1, GK, IL1RAPL1). We conclude that AI in the context of other genetic abnormalities should prompt chromosomal investigations in the absence of another unifying explanation.

Hypertriglyceridaemia unresponsive to multiple treatments.

A 52-year-old man with a longstanding history of hypertriglyceridaemia (approximately 7 mmol/L (600 mg/dL)), unresponsive to treatment, presented to a lipid-specialty clinic. Additional triglyceride-lowering therapies were added with no effect. It was then noted that despite the apparent hypertriglyceridaemia, his serum sample was clear. A 'glycerol blank' was then requested from an advanced lipid laboratory, which reported a triglyceride value of 0.7 mmol/L (62 mg/dL). These findings suggest isolated asymptomatic glycerol kinase deficiency (GKD) or 'pseudohypertriglyceridaemia'. The falsely elevated triglyceride values in such individuals are a result of excess serum glycerol and clinical laboratories measuring glycerol to report triglyceride concentrations. After discontinuation or modification of the patient's primary triglyceride-lowering agents, the lipid panels and triglyceride values remained comparable to previous readings. Recognition of asymptomatic GKD is important to prevent unnecessary treatment and overestimated cardiovascular risk.

Evaluation of Serum Oxidized Low-Density Lipoprotein in Renal Transplant Recipients and Hemodialysis Patients and Relation With Involved Variables.

OBJECTIVES: Disturbances in metabolism of lipo-proteins and oxidative modification of low-density lipoprotein contribute to cardiovascular disease and development of oxidative stress in patients under renal replacement therapy (hemodialysis and renal transplant). This study was designed to compare oxidized low-density lipoprotein levels and lipid profiles in renal transplant recipients and hemo-dialysis patients. MATERIALS AND METHODS: We investigated the concentration of oxidized low-density lipoprotein in hemodialysis (n = 38) and renal transplant (n = 59) patients who had no active inflammatory disease, liver disease, or malignancy, and results were compared to a control group (n = 30). RESULTS: Renal transplant recipients had hypercholesterolemia, hypertriglyceridemia, and increased oxidized low-density lipoprotein levels (P = .019) compared with the control group. Hemodialysis patients had moderate hypertriglyceridemia (not significant), hypercholesterolemia, decrease in high-density lipoprotein, and increase in oxidized low-density lipoprotein levels (P < .0001) compared with the control group. In the renal transplant group, oxidized low-density lipoprotein level had a negative correlation with the duration after transplant (r = -0.407; P = .026), positive association with cyclosporine level (r = 0.288; P = .04), and negative correlation with high-density lipoprotein level (r = -.30; P = .05); oxidized low-density lipo-protein/high-density lipoprotein ratio also had a positive correlation with cyclosporine level (r = 0.309; P = .027) and negative correlation with high-density lipoprotein level (r = -0.72; P < .001) in the renal transplant group and high-density lipoprotein in the hemodialysis group (r = -0.87; P < .001). Multiple stepwise regression analyses showed that oxidized low-density lipoprotein only was associated with cyclosporine level (R2 = 0.155; ß=0.393; P = .024). CONCLUSIONS: History of cardiovascular disease is the most important factor associated with end-stage renal disease, and high oxidized low-density lipoprotein level, oxidized low-density lipo-protein/high-density lipoprotein ratio, and high-density lipoprotein level may affect cardiovascular disease.

Xp21 deletion in female patients with intellectual disability: Two new cases and a review of the literature.

Xp21 continuous gene deletion syndrome is characterized by complex glycerol kinase deficiency (GK), adrenal hypoplasia congenital (NROB1), intellectual disability and/or Duchenne muscular dystrophy (DMD). The clinical features depend on the size of the deletion, as well as on the number and the nature of the encompassed genes. More than 100 male patients have been reported so far, while only a few cases of symptomatic female carriers have been described. We report here detailed clinical features and X chromosome inactivation analysis in two unrelated female patients with overlapping Xp21 deletions presenting with intellectual disability and inconstant muscular symptoms.