Question: What is (are) X-linked spondyloepiphyseal dysplasia tarda ?
Answer: X-linked spondyloepiphyseal dysplasia tarda is a condition that impairs bone growth and occurs almost exclusively in males. The name of the condition indicates that it affects the bones of the spine (spondylo-) and the ends (epiphyses) of long bones in the arms and legs. "Tarda" indicates that signs and symptoms of this condition are not present at birth, but appear later in childhood, typically between ages 6 and 10. Males with X-linked spondyloepiphyseal dysplasia tarda have skeletal abnormalities and short stature. Affected boys grow steadily until late childhood, when their growth slows. Male adult height ranges from 4 feet 10 inches to 5 feet 6 inches. Individuals with X-linked spondyloepiphyseal dysplasia tarda have a short trunk and neck, and their arms appear disproportionately long. Impaired growth of the spinal bones (vertebrae) causes the short stature seen in this disorder. The spinal abnormalities include flattened vertebrae (platyspondyly) with hump-shaped bulges, progressive thinning of the discs between vertebrae, and an abnormal curvature of the spine (scoliosis or kyphosis). Other skeletal features of X-linked spondyloepiphyseal dysplasia tarda include an abnormality of the hip joint that causes the upper leg bones to turn inward (coxa vara); a broad, barrel-shaped chest; and decreased mobility of the elbow and hip joints. Arthritis often develops in early adulthood, typically affecting the hip joints and spine.
Source: GHR

Question: How many people are affected by X-linked spondyloepiphyseal dysplasia tarda ?
Answer: The prevalence of X-linked spondyloepiphyseal dysplasia tarda is estimated to be 1 in 150,000 to 200,000 people worldwide.
Source: GHR