Is there a genomic link and common pathogenesis (postzygotic mutations in beta-actin) for Poland syndrome and Becker nevus syndrome?

I read with interest the excellent review of Poland syndrome by Hashim et al. (1). The investigators provide a current and comprehensive summary of all aspects of this extraordinary condition. Prominent features of Poland syndrome include pectoral muscle hypoplasia or aplasia, mammary hypoplasia and ipsilateral limb anomalies (1).

The researchers emphasize that several hypotheses have been suggested regarding the pathogenesis of Poland syndrome (1). The vascular disruption theory (resulting from a subclavian artery supply disruption sequence) is the favored mechanism of pathogenesis (2,3). However, a Poland syndrome patient with no arterial alteration has been described (4); therefore, at least in some patients with Poland syndrome, the vascular disruption theory may not be a uniform etiology for the development of this condition.

Becker nevus syndrome is a genodermatosis characterized by the presence of a Becker nevus (a circumscribed hyperpigmentation with hypertrichosis which often also has a concurrent smooth muscle hamartoma) associated with certain skin and extracutaneous abnormalities (5). Hypoplastic or absent breast and ipsilateral upper extremity skeletal abnormalities are present in several of the patients with Becker nevus syndrome (5). Indeed, it is rather remarkable that the morphologic presentation of Becker nevus syndrome has several phenotypic features similar to those observed in Poland syndrome.

The pathogenesis of Becker nevus syndrome has been demonstrated by Cai et al.: postzygotic mutations of the ACTB gene that codes for beta-actin (6). However, a definitive pathogenesis for Poland syndrome remains to be established (1,3). In addition to the other potential etiopathogeneses of Poland syndrome that Hashim et al. have summarized (1), based on the phenomenal clinical similarities demonstrated by Cai et al.’s Becker nevus syndrome patient who had unilateral left breast and pectoral muscle hypoplasia (6), I respectfully propose another etiology—that Poland syndrome may also result from postzygotic mutations in beta-actin (7).

In summary, Poland syndrome—similar to Becker nevus syndrome—has several systemic and dermatologic manifestations (1,8). In addition, both Poland syndrome and Becker nevus syndrome have identical phenotypic features (hypoplastic or absent breast and skeletal abnormalities of the ipsilateral upper extremity); these common features introduce the possibility that both syndromes share a common genomic aberration. Investigation as to whether or not patients with Poland syndrome have postzygotic mutations in beta-actin may be warranted.

Acknowledgments

Funding: None.

Footnote

Provenance and Peer Review: This article was a standard submission to the journal, Translational Pediatrics. The article did not undergo external peer review.

Conflicts of Interest: The author has completed the ICMJE uniform disclosure form (available at https://dx.doi.org/10.21037/tp-21-409). Philip R. Cohen, MD reports that he is a consultant for ParaPRO. He has received: (I) a consulting fee (once) with regards to Spinosad Topical Suspension, 0.9% for the topical treatment of scabies, and (II) a presentation fee (once) for participating in a filmed presentation regarding a general review of scabies.

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References

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