Type IXa Research Articles

A novel PHKA2 variant in a Chinese boy with glycogen storage diseases type IXa.

Glycogen storage diseases (GSDs) are a group of heterogeneous inherited metabolic disorders with an incidence of 4%-5%. There are 19 types of GSDs, making diagnosis one of the greatest challenges. The proband and his parents were referred to our hospital for genetic diagnosis. Ultrasound screening suggested hepatomegaly. A novel insertion variant NM_000292 c.1155_1156insT (p. 386N>*) in PHKA2 gene was identified using trio whole exome sequencing (Trio-WES), which resulted in the codon of amino acid 386 from asparagine to termination (p. 386N>*). The 3D mutant protein structure was predicted using AlphaFold, and the results showed that the truncated PHKA2 protein contained 385 of the 1,235 amino acids of the mature protein. We describe a previously unreported case of a GSDs IXa type Chinese boy caused by a novel PHKA2 variant. This clinical case contributes to the understanding of the characteristics of GSDs type IXa and expands the variants spectrum of genes related to GSDs type IXa. Our findings demonstrated the significance of genetic testing in the diagnosis of GSDs.

Sarcopenic obesity in a child with type IXa glycogenosis in combination with eosinophilic esophagitis and Legg–Calvé–Perthes disease

The article describes a clinical example of the development of sarcopenic obesity in a child with type IXa glycogen disease. The reasons for the development of sarcopenic obesity were, on the one hand, the lack of control over the child’s nutrition: excess consumption of easily digestible carbohydrates, fats and lack of protein in the actual diet and inactivity due to a child’s motor activity restriction in view of surgical interventions for Perthes’ disease, on the other. The article provides practical recommendations on the example of prescribing diet therapy to a child with a complex combination of type IX glycogenosis, sarcopenic obesity, Perthes disease, and eosinophilic esophagitis.

Identification of a novel deletion mutation in PHKA2 in a taiwanese patient with type IXa glycogen storage disease.

Identification of a novel deletion mutation in PHKA2 in a taiwanese patient with type IXa glycogen storage disease.

Hepatic glycogen storage diseases type 0, VI and IX: description of an italian cohort

BackgroundGlycogen storage disease (GSD) type 0, VI and IX are inborn errors of metabolism involving hepatic glycogen synthesis and degradation. We performed a characterization of a large Italian cohort of 30 patients with GSD type 0a, VI, IXa, IXb and IXc. A retrospective evaluation of genetical, auxological and endocrinological data, biochemical tests, and nutritional intakes was assessed. Eventual findings of overweight/obesity and insulin-resistance were correlated with diet composition.ResultsSix GSD-0a, 1 GSD-VI, and 23 GSD-IX patients were enrolled, with an age of presentation from 0 to 72 months (median 14 months). Diagnosis was made at a median age of 30 months, with a median diagnostic delay of 11 months and a median follow-up of 66 months. From first to last visit, patients gained a median height of 0.6 SDS (from − 1.1 to 2.1 SDS) and a median weight of 0.5 SDS (from − 2.5 to 3.3 SDS); mean and minimal glucose values significant improved (p < 0.05). With respect to dietary intakes, protein intake (g/kg) and protein intake (g/kg)/RDA ratio directly correlated with the glucose/insulin ratio (p < 0.05) and inversely correlated with HOMA-IR (Homeostasis model assessment of insulin resistance, p < 0.05), BMI SDS (p < 0.05) and %ibw (ideal body weight percentage, p < 0.01).ConclusionA prompt establishment of specific nutritional therapy allowed to preserve growth, improve glycemic control and prevent liver complication, during childhood. Remarkably, the administration of a high protein diet appeared to have a protective effect against overweight/obesity and insulin-resistance.

A novel PHKA2 variant in a Japanese boy with glycogen storage diseases type IXa.

A novel PHKA2 variant in a Japanese boy with glycogen storage diseases type IXa.

Generation of human induced pluripotent stem cell line, KRIBBi003-A, from urinary cells of a patient with glycogen storage disease type IXa

Glycogen storage disease type IXa (GSD IXa) is a rare genetic disorder characterized by phosphorylase kinase (PhK) deficiency, which leads to excessive glycogen accumulation in the liver. Urinary cells (UCs) were isolated from a GSD IXa patient and reprogrammed into induced pluripotent stem cells (iPSCs) using Sendai virus. The established iPSC line, KRIBBi003-A, exhibited pluripotency marker expression and a normal karyotype. The differentiation capacity of the cell line was confirmed by the differentiation of the three germ layers in vitro. The established iPSC line is a potential useful resource for disease modeling of GSD IXa.

The application of continuous glucose monitoring in the management of hepatic glycogen storage disease

Objective: Continuous glucose monitoring (CGM) were performed in children with hepatic glycogen storage disease (GSD) to accurately understand the situation of glucose levels during their treatment, and to provide support for optimizing their nutritional management. Methods: In this retrospective research, 42 patients with hepatic GSD who under went 72 h CGM were collected from Department of Pediatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology from October 2019 to January 2020. According to the genetic test results, they were divided into 5 groups: type Ⅰa, type Ⅰb, type Ⅲa, type Ⅵ and type Ⅸa. After long-term follow up and regular treatment, the clinical data (induding course, age, height, weight and biochemical parameters, etc.) on the day of CGM were summarized, and 72 h CGM were performed to assess the occurrence of hypoglycemia and hyperglycemia.χ² test, Fisher exact probability method, t test, analysis of variance or nonparametric test were used for comparison between groups. Results: Forty-two cases of hepatic GSD patients included 25 males and 17 females (20 cases of type Ⅰa, 3 cases of type Ⅰb, 10 cases of type Ⅲa, 3 cases of type Ⅵ and 6 cases of type Ⅸa).The age was 9.5 (6.7, 12.9) years, and the course of disease was 6.8 (5.1, 11.3) years. The average levels of glucose of the patients were all normal. However, the levels of standard deviation of blood glucose (SDBG) and mean amplitude of glycemic excursion (MAGE) were significantly different (F=2.747, 3.029,both P<0.05). Among them, the SDBG of type Ⅰa and Ⅲa were significantly higher than those of type Ⅸa ((1.10±0.36), (0.98±0.30) vs. (0.62±0.26) mmol/L, t=3.010, 2.440, both P<0.05), while the MAGE of type Ⅰ was higher than that of Ⅸa and Ⅲa ((2.3±0.9) mmol/L vs. (1.2±0.6) and (1.7±0.6) mmol/L, t=2.734, 2.302, both P<0.05, respectively). Conclusions: CGMS can accurately assess the fluctuations of blood glucose and effectively detect hidden hypoglycemia and hyperglycemia in hepatic GSD patients. For different types of hepatic GSD, individualized corn starch treatment doses should be given according to the different situation of blood glucose, so as to optimize the patient's treatment and improve their prognosis.

Glycogen storage disorder Type IXa and congenital hypothyroidism: A novel association

Glycogen storage disease (GSD) is a disorder of glycogen metabolism and GSDs are classified according to the enzyme deficiency and the affected tissue. Previously, an association of thyroid autoimmunity and hypothyroidism in patients with GSD has been reported. Here, we are presenting a rare association of congenital hypothyroidism with GSD IXa in a child who presented with progressive abdominal distension and hepatomegaly. GSD was suspected clinically and was confirmed by whole-exome sequencing

Glycogen Storage Disease IXa in a 9-year-old Filipino Boy with Short Stature: A Case Report

Glycogen storage disease (GSD) type IXa, due to a deficiency of hepatic phosphorylase b kinase, results in liver enlargement, growth retardation and fasting ketosis. Many are asymptomatic and do not require treatment. This is the first documented GSD IXa in a Filipino boy evaluated for short stature.

A novel PHKA2 mutation in a Chinese child with glycogen storage disease type IXa: a case report and literature review

BackgroundPHKA2 gene mutations can cause liver phosphorylase kinase (PhK) deficiency, resulting in glycogen storage disease type IXa (GSD IXa). Elevated liver transaminase levels and liver enlargement are the most frequent phenotypes of GSD IXa. However, whether the phenotypes are applicable to Chinese patients remains unclear.Case reportA boy aged 2 years and 8 months with a history of episodic fatigue and weakness since he was 2 years old was referred to our endocrinology clinic. Apart from symptomatic ketotic hypoglycemic episodes (palpitation, hand shaking, sweating, etc.), no abnormalities of liver transaminase levels or liver size were found. To identify the aetiology of his clinically diagnosed hypoglycaemia, the proband and his parents were screened for PHKA2 gene mutations by next-generation sequencing. A heterozygous mutation (c.2972C > G, p.G991A) in PHKA2 was found in the proband and his mother. Twenty-one Chinese cases with GSD IXa have been reported in the literature to date, and elevated liver transaminase levels (95%) and liver enlargement (91%) are the most frequent phenotypes of GSD IXa in Chinese patients. Hypoglycaemia may be one of the early onset symptoms in infants with GSD IXa.ConclusionsThis study enriches our knowledge of the PHKA2 gene mutation spectrum and provides further information about the phenotypic characteristics of Chinese GSD IXa patients.

Clinical and genetic characteristics of 17 Chinese patients with glycogen storage disease type IXa

Glycogen storage disease (GSD) type IXa is caused by PHKA2 mutation, which accounts for about 75% of all the GSD type IX cases. Here we first summarized the clinical data and analyzed the PHKA2 gene of 17 Chinese male patients suspected of having GSD type IXa. Clinical symptoms of our patients included hepatomegaly, growth retardation, and liver dysfunction. The clinical and biochemical manifestations improved and even disappeared with age. We detected 14 mutations in 17 patients, including 8 novel mutations; exons 2 and 4 were hot spots in this research. In conclusion, glycogen storage disease type IXa is a mild disorder with a favorable prognosis, and there was no relationship between genotype and phenotype of this disease.

A new variant in PHKA2 is associated with glycogen storage disease type IXa

Glucogenosis type IX is caused by pathogenic variants of the PHKA2 gene. Herein, we report a patient with clinical symptoms compatible with Glycogen Storage Disease type IXa. PYGL, PHKA1, PHKA2, PHKB and PHKG2 genes were analyzed by Next Generation Sequencing (NGS). We identified the previously undescribed hemizygous missense variant NM_000292.2(PHKA2):c.1963G>A, p.(Glu655Lys) in PHKA2 exon 18. In silico analyses showed two possible pathogenic consequences: it affects a highly conserved amino acid and disrupts the exon 18 canonical splice donor site. The variant was found as a “de novo” event.

Structured Dietary Management Dramatically Improves Marked Transaminitis, Metabolic and Clinical Profiles in Glycogen Storage Disease Type IXa

Abstract Glycogen storage disease type IXa (GSD IXa) presents in childhood with hepatomegaly, poor growth, and ketotic hypoglycemia. Clinical course is usually mild, often not requiring treatment with attenuation of symptoms with increasing age. The phenotypic spectrum has recently expanded to include more severe involvement with hepatic fibrosis or cirrhosis warranting dietary therapy. We report a 2-year-old boy with a severe phenotype of GSD IXa presenting with a massive hepatomegaly, significant transaminitis, recurrent ketotic hypoglycemia, and short stature. Aggressive dietary management with regular feeds, frequent uncooked cornstarch doses, and protein supplementation resulted in clinical improvements including enhanced growth velocity, energy levels, overall well-being, and reduction in hepatomegaly with restitutions in biochemical parameters. We concur with a recent report which proposed that GSD IXa is not always a mild condition but instead part of an expanding phenotypic spectrum warranting intensive dietary management to optimize metabolic control and quality of life.

Simultaneous GC-EI-MS determination of Delta9-tetrahydrocannabinol, 11-hydroxy-Delta9-tetrahydrocannabinol, and 11-nor-9-carboxy-Delta9-tetrahydrocannabinol in human urine following tandem enzyme-alkaline hydrolysis.

A sensitive and specific method for extraction and quantification of Delta(9)-tetrahydrocannabinol (THC), 11-hydroxy-Delta(9)-tetrahydrocannabinol (11-OH-THC), and 11-nor-9-carboxy-Delta(9)-tetrahydrocannabinol (THCCOOH) in human urine was developed and fully validated. To ensure complete hydrolysis of conjugates and capture of total analyte content, urine samples were hydrolyzed by two methods in series. Initial hydrolysis was with Escherichia coli beta-glucuronidase (Type IX-A) followed by a second hydrolysis utilizing 10N NaOH. Specimens were adjusted to pH 5-6.5, treated with acetonitrile to precipitate protein, and centrifuged, and the supernatants were subjected to solid-phase extraction. Extracted analytes were derivatized with BSTFA and quantified by gas chromatography-mass spectrometry with electron impact ionization. Standard curves were linear from 2.5 to 300 ng/mL. Extraction efficiencies were 57.0-59.3% for THC, 68.3-75.5% for 11-OH-THC, and 71.5-79.7% for THCCOOH. Intra- and interassay precision across the linear range of the assay ranged from 0.1 to 4.3% and 2.6 to 7.4%, respectively. Accuracy was within 15% of target concentrations. This method was applied to the analysis of urine specimens collected from individuals participating in controlled administration cannabis studies, and it may be a useful analytical procedure for determining recency of cannabis use in forensic toxicology applications.

Biochemical characteristics and increased tetraglucoside excretion in patients with phosphorylase kinase deficiency

Patients with glycogen storage disease type IXa present with infantile hepatomegaly and a specific growth pattern, and variable biochemical alterations in blood. We studied the clinical and biochemical characteristics including the urinary oligosaccharide excretion of seven unrelated children. The urinary tetraglucoside excretion was increased in four children, three of whom had persistently high cholesterol and triglyceride concentrations. We propose screening for urine tetraglucoside excretion and the measurement of serum cholesterol in patients with growth delay and/or hepatomegaly to assess a possible glycogenosis.

Susceptibility to -Mactam agents of Yersinia enterocolitica biotype 4, serotype O3 isolated in various parts of the world

Forty-eight human isolates of Yersinia enterocolitica of biotype 4, serotype O3 from various parts of the world were examined for susceptibility to 13 beta-lactam agents. The intracellular beta-lactamases of each of the 48 strains were examined. Isolates from Europe, Asia and Brazil (phage type VIII) or South Africa and Hungary (phage type IXa) produced both enzyme A and enzyme B, whereas isolates from New Zealand and Australia (phage type IXb) lacked the cephalosporinase enzyme B. Among the seven strains isolated in Canada belonging to phage type IXb, three strains expressed only enzyme A (group I) whereas the other four strains produced both enzymes A and B (group II). The high susceptibility to the combination of amoxycillin and clavulanate observed in one subtype was explained by the absence of the cephalosporinase enzyme B. A simple disk diffusion test with this antibiotic combination was shown to be effective in the detection of enzyme B in Y. enterocolitica 4/O3.