SNP Shot: Genomic Insights

Pseudoachondroplasia is a genetic condition affecting bone development. Initially mistaken for a variant of achondroplasia due to its impact on bone growth, it lacks the distinct facial characteristics associated with achondroplasia. Further investigation has confirmed that pseudoachondroplasia is a distinct genetic disorder.

A defining characteristic of pseudoachondroplasia is short stature. On average, adult males with this condition reach a height of approximately 120 centimeters (3 feet, 11 inches), while adult females typically reach 116 centimeters (3 feet, 9 inches). Though infants with pseudoachondroplasia exhibit normal length at birth, their growth rate deviates from the normal curve around the age of two.

Additional features commonly observed in individuals with pseudoachondroplasia include shortened limbs, a characteristic waddling gait, and joint pain beginning in childhood that often progresses to osteoarthritis. They may also experience excessive joint flexibility (hyperextensibility) in their hands, knees, and ankles, alongside restricted movement in their elbows and hips. Some individuals may exhibit outward or inward turning of the legs (valgus or varus deformity). In some instances, a windswept deformity, where one leg turns outward and the other inward, may be present. Spinal curvatures such as scoliosis or lordosis can also occur. Notably, people with pseudoachondroplasia have typical facial features, head size, and cognitive abilities.

Inheritance:

Pseudoachondroplasia follows an autosomal dominant inheritance pattern. This means that having only one copy of the mutated gene in each cell is enough to cause the condition. Affected individuals may inherit the mutated gene from one affected parent. However, the majority of cases are the result of a new mutation in the gene, arising spontaneously in individuals without any family history of pseudoachondroplasia.