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Licensed Unlicensed Requires Authentication Published by De Gruyter October 22, 2021

An atypical presentation of a pathogenic STK11 gene variant in siblings not fulfilling the clinical diagnostic criteria for Peutz-Jeghers Syndrome

  • Meera Shaunak EMAIL logo , Lucy Side , Nadeem Afzal and Justin Huw Davies ORCID logo



To report an atypical presentation of a pathogenic STK11 gene variant in siblings not fulfilling the clinical diagnostic criteria for Peutz-Jeghers Syndrome (PJS).

Case presentation

Two siblings presented with prepubertal gynaecomastia and bilateral macro-orchidism, without mucocutaneous pigmentation or gastrointestinal symptoms. There was no family history of PJS. Sibling 1 had unilateral gynaecomastia. Sibling 2 had bilateral gynaecomastia, advanced bone age and bilateral testicular microlithiasis, not indicative of a large-cell calcifying Sertoli cell tumour. Genetics revealed a paternally inherited heterozygous pathogenic STK11 variant (910C>T) in both siblings. The diagnosis was confirmed following the identification of multiple intestinal polyps in their father.


Prepubertal gynaecomastia and prepubertal macro-orchidism (testicular enlargement without virilisation), always warrant endocrinological investigation, with PJS being an important differential diagnosis. Children may not fulfil the clinical criteria for a diagnosis of PJS at presentation. Genetic testing and gastroenterological investigation of parents may aid diagnosis.

Corresponding author: Dr. Meera Shaunak, Department of Paediatric Endocrinology, University Hospital Southampton NHS Foundation Trust, Southampton SO16 6YD, UK, E-mail:

  1. Research funding: None declared.

  2. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  3. Competing interests: Authors state no conflict of interest.

  4. Informed consent: Informed consent was obtained from all individuals included in this case report.

  5. Ethical approval: Not applicable.


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Received: 2021-09-01
Accepted: 2021-10-03
Published Online: 2021-10-22
Published in Print: 2022-01-27

© 2021 Walter de Gruyter GmbH, Berlin/Boston

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