Approximately 50% of affected children have abnormal findings at birth (such as club foot or twisted metatarsals, cleft palate, inward curving fingers due to underdeveloped bones and brachydactyly, or ear swelling caused by injury during birth). Height is in the normal range before puberty. As adults, people with recessive MED are only slightly more diminished in stature, but within the normal range. Lateral knee radiography can show multi-layered patellae. Genetics
Multiple epiphyseal dysplasia (MED) encompasses a spectrum of skeletal disorders, most of which are inherited in an autosomal dominant form. However, there is an autosomal recessive form.Associated genes include COL9A1, COL9A2, COL9A3, COMP, and MATN3.Types include:

In the dominant form, mutations in five genes are causative: COMP (chromosome 19), COL9A1 (chromosome 6), COL9A2 (chromosome 1), COL9A3 (chromosome 20), and MATN3 (chromosome 2). However, in approximately 10%–20% of samples analyzed, a mutation cannot be identified in any of the five genes above, suggesting that mutations in other as-yet unidentified genes are involved in the pathogenesis of dominant MED.The COMP gene is mutated in 70% of the molecularly confirmed MED patients. Mutations are in the exons encoding the type III repeats (exons 8–14) and C-terminal domain (exons 15–19). The most common mutations in COL9A1 are in exons 8-10, in COL9A2 in exons 2-4, and in COL9A3 in exons 2-4. Altogether, those mutations cover 10% of the patients. The other 20% of affected people have mutations in MATN3 gene, all found within exon 2.
Fairbanks disease or multiple epiphyseal dysplasia (MED) is a rare genetic disorder (dominant form: 1 in 10,000 births) that affects the growing ends of bones. Long bones normally elongate by expansion of cartilage in the growth plate (epiphyseal plate) near their ends. As it expands outward from the growth plate, the cartilage mineralizes and hardens to become bone (ossification). In MED, this process is defective. Signs and symptoms
Children with autosomal dominant MED experience joint pain and fatigue after exercising. Their x-rays show small and irregular ossifications centers, most apparent in the hips and knees. There are very small capital femoral epiphyses and hypoplastic, poorly formed acetabular roofs. A waddling gait may develop. Knees have metaphyseal widening and irregularity while hands have brachydactyly (short fingers) and proximal metacarpal rounding. Flat feet are very common. The spine is normal but may have a few irregularities, such as scoliosis.By adulthood, people with MED are of short stature or in the low range of normal and have short limbs relative to their trunks. Frequently, movement becomes limited at the major joints, especially at the elbows and hips. However, loose knee and finger joints can occur. Signs of osteoarthritis usually begin in early adulthood.Children with recessive MED experience joint pain, particularly of the hips and knees, and commonly have deformities of the hands, feet, knees, or vertebral column (like scoliosis).