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Case Reports
. 2026 Jan 29;18(1):e102594.
doi: 10.7759/cureus.102594. eCollection 2026 Jan.

Myhre Syndrome Presenting With Congenital Proximal Radioulnar Synostosis: A Case Report

I-Shou Lin  1   2 , Hsiu-Jung Lee  1 , Wei-Ning Chang  3
Affiliations
Case Reports

Myhre Syndrome Presenting With Congenital Proximal Radioulnar Synostosis: A Case Report

I-Shou Lin et al. Cureus. .

Abstract

Myhre syndrome (MS) is a rare, autosomal dominant multisystem disorder. Clinical features include short stature, variable degrees of intellectual disability, distinctive facial dysmorphism, musculoskeletal abnormalities, cardiopulmonary disorders, and abnormal sexual development. We report on an 11-year-old male Taiwanese patient who was initially referred to our genetic counseling clinic due to congenital proximal radioulnar synostosis (PRUS) and clinical suspicion of mucopolysaccharidosis. A pathogenic heterozygous missense variant in SMAD4, c.1498A>G (p.Ile500Val), was subsequently identified, confirming the diagnosis of MS. This case demonstrates the typical clinical phenotype along with the unique finding of PRUS, which has not been previously reported in association with this syndrome. This report highlights PRUS as a rare skeletal manifestation, expanding the known clinical spectrum of MS and providing valuable insights for clinical recognition.

Keywords: case report; musculoskeletal abnormalities; myhre syndrome; proximal radioulnar synostosis; smad4.

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Conflict of interest statement

Human subjects: Informed consent for treatment and open access publication was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

Figures

Figure 1
Figure 1. Radiographic findings of the bilateral elbows
(A) AP and (B) lateral radiographs of the left elbow; (C) AP and (D) lateral radiographs of the right elbow. The images demonstrate bilateral PRUS, characterized by the osseous fusion of the proximal radius and ulna (indicated by arrows). AP, anteroposterior; PRUS, proximal radioulnar synostosis
Figure 2
Figure 2. Chest radiograph
The image demonstrates paddle-shaped widening of the ribs (arrow).
Figure 3
Figure 3. Sanger sequencing chromatogram of the SMAD4 gene
The arrow indicates the heterozygous missense variant c.1498A>G (p.Ile500Val), confirming the diagnosis of Myhre syndrome.
Figure 4
Figure 4. Three-generation family pedigree
The pedigree illustrates the inheritance pattern and the clinical status of family members. Symbols follow standard pedigree nomenclature. HTN, hypertension; DM, diabetes mellitus
See this image and copyright information in PMC

References

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