A Mild Case of Pseudoachondroplasia in a Child: Lessons for Long-Term Primary Care

Authors

• Alec J. Pupo D.O., Philadelphia College of Osteopathic MedicineFollow
• Connor J. Stinson D.O., Philadelphia College of Osteopathic MedicineFollow
• Autumn Dye D.O., Philadelphia College of Osteopathic MedicineFollow

Abstract

Background: Pseudoachondroplasia (PSACH) is a rare autosomal dominant skeletal dysplasia caused by pathogenic variants in the cartilage oligomeric matrix protein (COMP) gene. It is classically characterized by early-onset growth failure, disproportionate short stature, progressive epiphyseal dysplasia, and premature degenerative joint disease. Although phenotypic variability has been reported, PSACH is often regarded as a uniformly severe condition with predictable orthopedic morbidity.

Case Presentation: We report an eleven-year-old female with genetically confirmed PSACH who demonstrates an unexpectedly mild clinical phenotype, despite a maternal history of severe disease requiring bilateral total hip replacement during adolescence. The patient exhibited mild hip dysplasia, evolving genu valgum, intermittent lower-extremity pain, and dysmorphic epiphyses, but lacked hallmark features including rhizomelic limb shortening, spinal deformity, or significant growth restriction. Longitudinal growth analysis revealed preservation of linear growth within normative percentile ranges. Her clinical course has been managed conservatively with orthopedic surveillance and physical therapy. Genetic testing confirmed a heterozygous COMP mutation. Additional evaluation by pediatric neurology for abnormal movements is ongoing and appears unrelated to PSACH. Care was coordinated through an interdisciplinary model involving primary care pediatrics, orthopedic surgery, medical genetics, physical therapy, and neurology.

Discussion: This case highlights substantial intrafamilial phenotypic variability in COMP-associated disorders and supports the concept of PSACH as a clinical spectrum rather than a uniformly severe dysplasia. The patient’s mild presentation contrasts sharply with her mother’s severe disease, underscoring the limitations of parental phenotype as a predictor of clinical course. Recognition of milder PSACH phenotypes is essential to avoid diagnostic delay, misclassification, and inaccurate prognostication. Importantly, this case also illustrates the central role of primary care in interdisciplinary management: integrating subspecialty findings, prioritizing functional outcomes, supporting conservative treatment when appropriate, and maintaining longitudinal continuity.

Conclusion: PSACH exhibits significant genotype–phenotype heterogeneity, even among first-degree relatives. Individualized prognostication and longitudinal multidisciplinary follow-up are essential, particularly in patients with mild or atypical presentations. Interdisciplinary care anchored by integrative primary care provides a framework for translating complex genetic diagnoses into meaningful, patient-centered management while reducing diagnostic overshadowing and unnecessary intervention.

Recommended Citation

Pupo, Alec J. D.O.; Stinson, Connor J. D.O.; and Dye, Autumn D.O. (2026) "A Mild Case of Pseudoachondroplasia in a Child: Lessons for Long-Term Primary Care," The Journal of Integrated Primary Care: Vol. 2: Iss. 4, Article 6.
Available at: https://digitalcommons.pcom.edu/jipc/vol2/iss4/6