SNP Shot: Genomic Insights

Multicentric osteolysis, nodulosis, and arthropathy (MONA) is a rare, inherited disorder marked by bone tissue loss (osteolysis), primarily affecting the hands and feet. MONA encompasses what was previously known as nodulosis-arthropathy-osteolysis (NAO) syndrome. While potentially related, it's uncertain if Torg syndrome is a variant of MONA or a distinct condition arising from a different genetic mutation.

Typically, MONA presents with bone loss initially in the hands and feet, resulting in pain and restricted mobility. The bone abnormalities can progress to other areas, affecting joints like the elbows, shoulders, knees, hips, and spine (arthropathy). Osteopenia (reduced bone mineral density) and osteoporosis (bone thinning) are common throughout the skeleton in individuals with MONA, increasing fracture risk and contributing to short stature.

A characteristic feature is the development of subcutaneous nodules, firm, benign lumps beneath the skin, especially on the soles of the feet. Some individuals exhibit skin abnormalities, such as patches of thickened, darkened, and leathery skin. Other possible features of MONA include corneal opacity (clouding of the cornea), hypertrichosis (excessive hair growth), gum overgrowth, heart anomalies, and distinctive, "coarse" facial features.

Inheritance:

MONA follows an autosomal recessive inheritance pattern. This means an individual must inherit two copies of the mutated gene (one from each parent) to develop the condition. The parents, carrying only one copy of the mutated gene, are usually asymptomatic carriers.