Two novel mutations in the ANTXR2 gene in a Chinese patient suffering from hyaline fibromatosis syndrome: A case report.

ABSTRACT

Hyaline fibromatosis syndrome (HFS; MIM 228600) is a rare autosomal recessive disorder characterized by the abnormal growth of hyalinized fibrous tissue at subcutaneous regions on the scalp, ears and neck. The disease is caused by either a homozygous or compound heterozygous mutation of the anthrax toxin receptor 2 (ANTXR2) gene. The present study describes a patient with HFS confirmed by clinical examination as well as histopathological and genetic analyses. Numerous painless and variable­sized subcutaneous nodules were observed on the scalp, ear, trunk and four extremities of the patient. With increasing age, the number and size of the nodules gradually increased in the patient. The patient additionally presented with severe gingival thickening and developed pearly papules on the ears, back and penis foreskin. Biopsies of ear nodules revealed that the tumor was located in the dermis, and no marked alterations were observed in the epidermis compared with healthy patients. Spindle­shaped or round tumor cells were revealed to be immersed in the eosinophilic hyaline ground substance. Furthermore, a skeletal X­ray of the patient revealed multiple low­density imaging on the right distal humerus. Compound heterozygous mutations in the ANTXR2 gene were identified in the patient c.470_472del in exon 5 and c.1073 delC in exon 13. c.470_472del were revealed to be inherited from his mother and father, respectively. These two mutations, c.470_472del and c.1073 delC, to the best of our knowledge, have not previously been identified. Identification of the mutations in ANTXR2 may make prenatal diagnosis of HFS possible during future pregnancies.