Glycogen storage disease - Glycogenosis

Japanese: 糖原病 - とうげんびょう（英語表記）Glycogenosis

What is the disease?

Glycogen, like fat, is one of the stored energy sources in the body, and is stored in large amounts in the liver and muscles. When you are fasting, glycogen in the liver is broken down into glucose and released into the blood, which is then used throughout the body. Glycogen in the muscles is broken down during exercise, which requires a large amount of energy in a short period of time, and used by the muscles.

Glycogen storage diseases are diseases in which the utilization of glycogen is impaired, resulting in abnormal accumulation of glycogen in tissues. There are about 10 types of the disease, and depending on the tissues in which glycogen accumulates, they are classified as liver (hepatic type), muscle (muscle type), liver and muscle ( Liver muscle ( Kankin ) Type), Myocardium ( Shinkin ) It is classified as (myocardial type).

What is the cause?

The majority of cases are caused by genetic abnormalities in various enzymes involved in the breakdown of glycogen. Autosomal recessive ( High school student radio station ) And some X chain ( Rensa ) It is inherited recessively.

How symptoms manifest

In the hepatic type, the main symptoms are hypoglycemia, liver enlargement (swelling and becoming larger), and short stature. Glucose produced from glycogen in the liver is released into the blood and used by various tissues (especially the brain). Hypoglycemia impairs brain function, causing a range of symptoms from mild to severe. coma ( Today ) Depending on the level of blood sugar, various symptoms can occur, ranging from severe consciousness disorder to dizziness. Glycogen accumulates in the liver along with fat, causing the liver to swell, and in children, the abdomen may appear large and swollen.

In adulthood, it is benign. Hepatic adenoma ( Kansenshu ) It is necessary to be careful because it may cause cancer and become malignant. Doll-like face ( Doll making contest ) , short stature, Hyperlactatemia ( Admissions certificate ) , hyperlipidemia, Hyperuricemia ( Congratulations on your graduation ) , Cirrhosis ( Sightseeing ) etc. may also be accepted.

In the muscular type, symptoms include fatigue during strenuous exercise, muscle weakness, muscle pain, and myoglobinuria (brown urine) due to muscle breakdown.

In the hepatic muscle type, symptoms of both are seen, while in the myocardial type, the heart becomes enlarged and symptoms of heart failure appear.

Testing and diagnosis

It is diagnosed based on symptoms, MRI and CT of liver and muscles, the stress test established by Fernandez et al., confirmation of glycogen accumulation by liver and muscle biopsy, measurement of enzyme activity in blood, liver and muscle tissue, etc. Recently, a disease type that can be easily diagnosed by genetic analysis has also become known.

Treatment methods

For hepatic type, the goal is to maintain blood sugar levels by giving special milk and meals in frequent divided portions. If nighttime hypoglycemia is a problem, tube feeding may be used or cornstarch may be given before bedtime or at night. Depending on the type of disease, lactose, galactose, fructose, etc. may be restricted. For muscular type, avoiding strenuous exercise and a high-protein diet may be effective. Liver transplants are effective treatments for hepatic type, and heart transplants are effective for severe myocardial type.

What to do if you notice an illness

You should see a doctor who specializes in inborn errors of metabolism.

Kiyoshi Hayasaka

Glycogen storage disease
Glycogen storage disease
(Diseases caused by genetic factors)

What is the disease?

Carbohydrates absorbed from the digestive tract are stored in the body as glycogen, mainly in the liver. Due to enzyme abnormalities related to glycogen metabolism, there are two types of hepatic disease, in which glycogen accumulates mainly in the liver, and cardiac/muscular disease, which is characterized by muscle symptoms.

How symptoms manifest

In hepatic glycogen storage disease, the glycogen stored in the liver cannot be utilized, leading to hepatomegaly and hypoglycemia, and gradually to a noticeable short stature. Depending on the type of disease, symptoms such as persistent nosebleeds and a high susceptibility to infections may appear. gout ( Common ) , urinary stones, renal failure, Hepatic adenoma ( Kansenshu ) This may also result in.

In the cardiac and muscular type, muscle weakness and heart failure occur.

Treatment methods

The hepatic type is caused by eating frequent meals or consuming cornstarch, which is slowly digested and absorbed by the body. β ( beta ) We provide dietary therapy using starch and milk for glycogen storage disease, as well as treatment tailored to each symptom.

In the cardiac and muscular type, in addition to symptomatic treatment, replacement therapy for the missing enzyme may be performed.

Source: Houken “Sixth Edition Family Medicine Encyclopedia” Information about the Sixth Edition Family Medicine Encyclopedia

Japanese:

どんな病気か

　糖原（グリコーゲン）は、脂肪と同様に体のなかの貯蔵エネルギーのひとつであり、とくに肝臓と筋に多く蓄えられています。肝臓の糖原は、空腹時にブドウ糖にまで分解されて血液中に放出され、全身で利用されます。筋の糖原は、短時間に大きなエネルギーを要する運動時に分解され、筋で用いられます。

　糖原病は、糖原の利用が障害され、結果として組織に糖原が異常に蓄積する病気です。10種前後の病型があり、蓄積する組織にしたがって肝臓（肝型）、筋（筋型）、肝臓と筋（肝筋(かんきん)型）、心筋(しんきん)（心筋型）に分類されます。

原因は何か

　糖原の分解に関係する各種酵素の遺伝子異常が原因で、大部分は常染色体劣性遺伝(じょうせんしょくたいれっせいいでん)し、一部はX連鎖(れんさ)劣性遺伝します。

症状の現れ方

　肝型では、低血糖、肝臓の腫大（はれて大きくなる）、低身長などが主な症状です。肝臓の糖原から生成されたブドウ糖は血液中に放出され、各組織で（とくに脳など）で利用されます。低血糖になると脳のはたらきが障害され、頭がぼーっとする程度の軽いものから昏睡(こんすい)となる重い意識障害まで、血糖の低さにしたがってさまざまな症状が認められます。肝臓に糖原が脂肪とともに蓄積され、肝臓が腫大し、子どもではおなかが大きくふくらんで見えることもあります。

　成人後には良性の肝腺腫(かんせんしゅ)ができて、悪性化することもあるので、注意が必要です。また、人形様顔貌(にんぎょうようがんぼう)、低身長、高乳酸血症(こうにゅうさんけっしょう)、高脂血症、高尿酸血症(こうにょうさんけっしょう)、肝硬変(かんこうへん)などが認められることもあります。

　筋型では、激しい運動時の疲労、筋力の低下、筋肉痛、筋の崩壊によるミオグロビン尿（褐色尿）などが認められます。

　肝筋型では両者の症状が認められ、心筋型では心臓が拡大し、心不全の症状を示します。

検査と診断

　症状、肝・筋のMRIやCT、フェルナンデスらにより確立された負荷試験、肝・筋生検による糖原の蓄積の確認、血液、肝、筋組織を用いた酵素活性の測定などにより診断されます。最近では、遺伝子解析により簡単に診断される病型も知られています。

治療の方法

　肝型では、特殊ミルクや食事を頻回に分けて与え、血糖の維持を図ることが目標になります。夜間の低血糖が問題になる場合には、経管栄養を施したり、就寝前や夜間にコーンスターチを与えます。病型によっては、乳糖、ガラクトース、果糖などを制限します。筋型では、激しい運動を避け、高蛋白食が有効なこともあります。なお、肝型では肝移植、重症心筋型では心移植が有効な治療法です。