Blood glucose trends in glycogen storage disease type Ia: A cross-sectional study

BACKGROUND

Glycogen storage disease type Ia (GSDIa) is caused by biallelic pathogenic variants in the glucose-6-phosphatase gene (G6PC) and mainly characterized by hypoglycemia, hepatomegaly, and renal insufficiency. Although its symptoms are reportedly mild in patients carrying the G6PC c.648G>T variant, the predominant variant in Japanese patients, details remain unclear. Therefore, we examined continuous glucose monitoring (CGM) data and daily nutrition intake to clarify their associations in Japanese patients with GSDIa with G6PC c.648G>T.

METHODS

This cross-sectional study enrolled 32 patients across 10 hospitals. CGM was performed for 14 days, and nutritional intake was recorded using electronic diaries. Patients were divided according to genotype (homozygous/compound heterozygous) and age. The durations of biochemical hypoglycemia and corresponding nutritional intake were analyzed. Multiple regression analysis was performed to identify factors associated with the duration of biochemical hypoglycemia.

RESULTS

Data were analyzed for 30 patients. The mean daily duration of hypoglycemia (<4.0 mmol/L) in the homozygous group increased with age (2-11 years [N = 8]: 79.8 min; 12-18 years [5]: 84.8 min; ≥19 years [10]: 131.5 min). No severe hypoglycemic symptoms were recorded in the patients' diaries. The mean frequency of snack intake was approximately three times greater in patients aged 2-11 years (7.1 times/day) than in those aged 12-18 years (1.9 times/day) or ≥19 years (2.2 times/day). Total cholesterol and lactate were independently associated with the duration of biochemical hypoglycemia.

CONCLUSION

Although nutritional therapy prevents severe hypoglycemia in patients with GSDIa with c.648G>T, patients often experience asymptomatic hypoglycemia. This article is protected by copyright. All rights reserved.

A glycogen storage disease type 1a patient with type 2 diabetes

Background

Glycogen storage disease type 1a (GSD1a) is an inborn genetic disease caused by glucose-6-phosphatase-α (G6Pase-α) deficiency and is often observed to lead to endogenous glucose production disorders manifesting as hypoglycemia, hyperuricemia, hyperlipidemia, lactic acidemia, hepatomegaly, and nephromegaly. The development of GSD1a with diabetes is relatively rare, and the underlying pathogenesis remains unclear.

Case presentation

Here we describe a case of a 25-year-old Chinese female patient with GSD1a, who developed uncontrolled type 2 diabetes mellitus (T2DM) as a young adult. The patient was diagnosed with GSD1a disease at the age of 10 and was subsequently treated with an uncooked cornstarch diet. Recently, the patient was treated in our hospital for vomiting and electrolyte imbalance and was subsequently diagnosed with T2DM. Owing to the impaired secretory function of the patient’s pancreatic islets, liver dysfunction, hypothyroidism, severe hyperlipidemia, and huge hepatic adenoma, we adopted diet control, insulin therapy, and hepatic adenoma resection to alleviate this situation. The WES discovered compound heterozygous mutations at the exon 5 of G6PC gene at 17th chromosome in the patient, c.648G>T (p.L216 L, NM_000151.4, rs80356484) in her father and c.674T>C (p.L225 P, NM_000151.4, rs1555560128) in her mother. c.648G>T is a well-known splice-site mutation, which causes CTG changing to CTT at protein 216 and creates a new splicing site 91 bp downstream of the authentic splice site, though both codons encode leucine. c.674T>C is a known missense mutation that causes TGC to become CGC at protein 225, thereby changing from coding for leucine to coding for proline.

Conclusion

We report a rare case of GSD1a with T2DM. On the basis of the pathogenesis of GSD1a, we recommend attentiveness to possible development of fasting hypoglycemia caused by GSD and postprandial hyperglycemia from diabetes. As the disease is better identified and treated, and as patients with GSD live longer, this challenge may appear more frequently. Therefore, it is necessary to have a deeper and more comprehensive understanding of the pathophysiology of the disease and explore suitable treatment options.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01344-3.

Case Report: Glycogen Storage Disease Type Ia in a Chinese Child Treated With Growth Hormone

BACKGROUND

Glycogen storage disease type Ia is a rare metabolic disorder that leads to excessive glycogen and fat accumulation in organs, characterized by hepatomegaly, hypoglycemia, lactic acidemia, hyperlipidemia, hyperuricemia, puberty delay, and growth retardation. Here, we report on a patient with glycogen storage disease type Ia treated with growth hormone.

CASE PRESENTATION

A 10-year-old boy had growth retardation for 6 years, and was admitted to clarify the cause of his short stature. We found that his bone age was 5.5 years, significantly lower than his physical age, while his serum IGF-1 and IGFBP-3 were 23.30 and 1620.0 ng/mL, respectively, both lower than normal. His medical history revealed that he had suffered from steatohepatitis, hyperlipidemia, and hypoglycemia since he was 11 months of age. Whole exome sequencing (WES) showed compound heterozygous mutations in exons 2 and 5 of the glucose-6-phosphatase (G6PC) gene on chromosome 17: c.G248A (p.R83H) and c.G648T (p.L216L). The patient was finally diagnosed with GSD Ia. After growth hormone (GH) treatment and corn starch therapy for 14 months, his height significantly increased (by 13 cm). The serum IGF-1 level increased to the normal range but his lipid levels and liver function did not significantly increase.

CONCLUSION

We describe a young patient with a compound heterozygous G6PC variant in a Chinese family; his height increased significantly after growth hormone and corn starch interventions. This case emphasizes that WES is essential for early diagnosis, and that growth hormone treatment may increase the height of patients with GSD Ia safely.

An infant presenting with extreme hypertriglyceridemia diagnosed as glycogen storage disease type Ia

Background Marked hypertriglyceridemia in infancy is extremely rare. Patients with severe hypertriglyceridemia in early life may be unmasked by a primary or secondary cause. Case presentation A female infant was born in a good condition with normal Apgar scores. No special clinical symptoms and signs had been found within the first two months of life. Poor oral intake and failure to thrive were two main clinical manifestations when she was referred to our hospital at the age of 3.5 months. The milky serum was the only one characteristic presentation. Laboratory testing showed extremely high level of triglycerides, cholesterol and lactate. Many other laboratory indexes cannot be detected because of severe hyperlipemic samples. Multi-gene panel testing for 249 genes about genetic and metabolic liver disease were performed. Gene analysis revealed a G6PC gene deficiency. The patient was a homozygote for c.248G > A, p.R83H and her parents were both the heterozygotes. The infant had been diagnosed as glycogen storage disease type Ia. Conclusions We report an infant presenting with extreme hypertriglyceridemia diagnosed as glycogen storage disease type Ia by genetic testing. The gene panel can be used to confirm the diagnosis and delineate the exact type of glycogen storage disease, which could ultimately really help to reduce unnecessary tests and invasive examinations. Serum lipid should be close monitoring in order to prevent the complications and improve the prognosis.

A patient with glycogen storage disease type Ia combined with chronic hepatitis B infection: a case report

BACKGROUND

Glycogen storage disease type I (GSD I), also known as von Gierk disease, is a metabolic disorder leading to the excessive accumulation of glycogen and fat in organs, characterized by hepatomegaly, hypoglycemia, lactic acidemia, hyperlipidemia, hyperuricemia, puberty delay and growth retardation, which can be indicated by height, weight, blood glucose and blood lipids.

CASE PRESENTATION

Here we present a 16-year-old male patient with GSD Ia complicated with hepatic adenoma and combined with hepatitis B. As a chronic hepatitis B patient, the patient was admitted to hospital in order to further clarify the nature of hepatic space occupancy because of suspicion of hepatocellular carcinoma. However, the imaging studies did not support hepatocellular carcinoma certainly. And by tracing his clinical history, we suggested that he might suffer from GSD I. Finally the diagnosis was confirmed by MRI (Gd-EOB-DTPA), liver biopsy and whole exome sequencing (WES). The WES discovered a homozygous point mutation at the exon 5 of G6PC gene at 17th chromosome, c.G648 T (p.L216 L, NM_000151, rs80356484). This pathogenic mutation causes CTG changing to CTT at protein 216. Though both codons encode leucine, this silent mutation creates a new splicing site 91 bp downstream of the authentic splice site. According to previous research, this mutation is a disease causal variant for GSD Ia, and has a high frequency among GSD patients in China and Japan. This patient was finally diagnosed as GSD Ia complicated with hepatic adenoma and combined with chronic hepatitis B, and received corn starch therapy immediately after GSD was suspected. After receiving corn starch therapy, the height and weight of the patient were increased, and the secondary sexual characteristics were developed, including beard, pubic hair and seminal emission. Unexpectedly, the liver adenomas were still increasing, and we did not find any cause to explain this phenomenon.

CONCLUSION

This patient was diagnosed as GSD Ia combined with chronic hepatitis B, who responded to corn starch intervention. For childhood patients with hypoglycaemia, hyperlipidemia, puberty delay and growth retardation, GSD should be considered. Gene sequencing is valuable for the quick identification of GSD subtypes.