Ricki Carroll, MD

Characteristic clinical and radiographic findings can establish early suspicion for achondroplasia, while molecular and prenatal testing are helping clinicians confirm the diagnosis sooner.

Recognizing and Diagnosing Achondroplasia

In this episode, “Recognizing and Diagnosing Achondroplasia,” the panelists explore how achondroplasia is identified clinically and radiographically and how genetic testing can confirm the diagnosis.

The discussion begins with the characteristic phenotype seen in infants with achondroplasia. The panel highlights disproportionate shortening of the limbs, particularly rhizomelic shortening of the proximal extremities, along with macrocephaly, midface hypoplasia, and characteristic findings involving the hands and joints. For clinicians experienced in skeletal dysplasias, this combination of features can make the diagnosis highly recognizable. The panel then reviews radiographic findings that can further support the diagnosis, including characteristic changes involving the pelvis, acetabula, and proximal femur. Once achondroplasia is suspected, molecular confirmation of an FGFR3 mutation becomes an important step before treatment discussions begin.

Prenatal identification is also addressed. The experts note that achondroplasia is often not apparent on the standard 20-week anatomy scan, but third-trimester imaging may reveal shortened long bones, frontal bossing, or midface abnormalities that raise suspicion. They also discuss the increasing availability of noninvasive prenatal testing using maternal blood to detect the characteristic FGFR3 mutation once the condition is suspected. Together, these advances are helping move diagnosis earlier in the patient journey and may provide families with additional time for counseling and preparation before or shortly after birth.

The next episode, “Recognizing the Multisystem Burden of Achondroplasia,” will examine what happens after diagnosis. The panel will discuss the neurologic, respiratory, skeletal, and developmental complications that require ongoing surveillance throughout childhood.

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Achondroplasia is driven by overactive FGFR3 signaling that disrupts normal growth plate function. The panel explains how this molecular pathway affects endochondral bone growth and provides the foundation for understanding targeted treatment.

Understanding the Pathophysiology of Achondroplasia

Welcome back to another HCPLive Peer Exchange series. In this episode titled, “Understanding the Pathophysiology of Achondroplasia,” the panel reviews the molecular basis of achondroplasia and the role of fibroblast growth factor receptor 3 (FGFR3) in skeletal growth and development. The discussion begins with the identification of FGFR3 as the gene responsible for achondroplasia and its normal function in regulating chondrocyte proliferation. The panel explains that most appendicular bones and portions of the axial skeleton develop through endochondral ossification, a process that depends on carefully balanced signaling within the growth plate.

Under normal conditions, FGFR3 acts as one of several signals that restrain chondrocyte proliferation. In achondroplasia, a gain-of-function mutation causes FGFR3 signaling to become overactive, creating an excessive inhibitory effect on chondrocyte proliferation and differentiation. This disrupts normal endochondral ossification and leads to impaired longitudinal bone growth and the characteristic skeletal phenotype associated with achondroplasia. By establishing the underlying biology first, the panel provides important context for the remainder of the discussion. Understanding how excessive FGFR3 signaling affects skeletal development also helps explain why contemporary therapies seek to influence this pathway and restore a more favorable balance in growth plate signaling.

In the next episode, “Recognizing and Diagnosing Achondroplasia,” panelists will move from molecular biology to the clinical presentation of the disease. They will discuss the physical and radiographic findings that raise suspicion for achondroplasia and the role of genetic and prenatal testing in confirming the diagnosis.

Ricki Carroll, MD

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