カルパイノパチー（LGMD2A）の2剖検例の臨床病理学的検討

A Clinicopathological Investigation of Two Autopsy Cases of Calpainopathy (LGMD2A)

肢帯型筋ジストロフィー2A型（LGMD2A）の2家系2剖検例を報告する。症例1は72歳時に呼吸不全・心不全で死亡，症例2は70歳時に虚血性心筋症・全身性循環不全で死亡した。症例1では記憶障害，そして2例とも大脳萎縮がみられたが，神経細胞に特異的変化は認められなかった。2例とも不完全右脚ブロックを呈し，症例2の洞房結節では虚血性変化を伴う脂肪化が認められた。LGMD2Aでは，カルパイン3異常により骨格筋の障害をきたすが，心伝導障害の合併にも留意する必要がある。

Abstract

In this study, we compared the clinicopathological findings of two autopsy cases of patients with calpainopathy (LGMD2A) from different families.

The patient in case 1 was a 72-year-old man with a history of type 2 diabetes mellitus. He exhibited recent memory impairments from the age of 70. ECG revealed an incomplete right bundle branch block. A homozygous frameshift mutation c.1796dupA was found in the CAPN3 gene. Cause of death was respiratory insufficiency and heart failure. The patient in case 2 was a 70-year-old man with a history of hypertension. ECG revealed an incomplete right bundle branch block. A homozygous missense mutation c.1080G＞C (p.Trp360Cys) in CAPN3 gene was identified. Cause of death was ischemic cardiomyopathy and systemic circulatory failure.

In both cases, muscle pathology revealed severe dystrophic changes. In case 2, cardiac hypertrophy and old myocardial infarcts with stenosis of coronary arteries were observed. Histological examination of the sinoatrial node showed fatty infiltration with ischemic changes in case 2. In both cases, the patients' brains showed cerebral atrophy and well preserved neurons.

Calpain 3 abnormality was correlated with skeletal muscle involvement. It should be considered that LGMD2A might be complicated by dysfunction of the cardiac conduction system.

(Received October 9, 2013; Accepted January 20, 2014; Published September 1 2014)