SM is often inherited as an autosomal dominant trait of pachyonychia congenita type 2.The presence of multiple pilosebaceous cyst in PC-2 is the predominant feature distinguishing PC-2 from PC-1.

• SM也可为多种综合征的一种表现，如先天性厚甲症-2 型(pachyonychia congenita-2 ,PC-2型)，多发性皮脂腺囊肿是PC-2型与PC-1型鉴别的主要特征。