Interactive Quiz: Joint Pain

Answer: Consult a genetics specialist

Genetics, as well as dermatology, specialists were consulted, with further testing confirming the diagnosis of infantile systemic hyalinosis (ISH). Genetic test results were positive for a homozygous mutation of the anthrax toxin receptor gene (ANTXR2), confirming the diagnosis of ISH.

A dermatologist performed a punch biopsy of a hyperpigmented lesion on the infant’s left foot, the results of which demonstrated sclerosis of the deep dermis with elevation of the eccrine coils, with apparent loss of the peri-eccrine fat, and with relative loss of the CD34⁺dermal dendritic cells at the base of the specimen.