Abstract
Objectives
We report an uncommon case of severe hypercalcemia in an infant with unbalanced translocation of chromosomes 2 and 8 with 2p duplication. After ruling out all the possible etiologies of hypercalcemia, we speculated a potential contribution of 2p duplication involving 225 genes.
Case presentation
An 11-month old female infant with global developmental delay, failure to thrive (FTT), hypotonia, amblyopia, constipation, and recent onset emesis was admitted to the hospital after an incidental diagnosis of severe hypercalcemia. Labs revealed normal serum phosphate, serum 25 (OH) vitamin D levels, and low serum parathyroid hormone (PTH) level. Elevated urinary calcium to creatinine ratio ruled out the possibility of hypocalciuric hypercalcemia. Endocrinological evaluations, including thyroid function test, Adrenocorticotropic hormone (ACTH), Cortisol, Insulin like growth factor 1 (IGF-1) were all normal. Transient elevation of parathyroid hormone related peptide (PTHrP) level was noted, but skeletal survey, chest X-ray and lab values including low 1,25 (OH)2 cholecalciferol, lactate dehydrogenase (LDH), uric acid (UA), erythrocyte sedimentation rate (ESR) excluded granulomatous diseases and malignancies. Further evaluation with chromosomal microarray (CMA) and whole exome gene sequencing (WES) showed an unbalanced chromosomal translocation with 2p duplication involving 225 genes. The infant showed an improvement with medical management.
Conclusions
2p duplication syndrome is a rare syndrome characterized by developmental delay, feeding problems, FTT, hypotonia, constipation, and unusual facial features as noted in our case. However, hypercalcemia has been only reported once earlier in 2p duplication syndrome, which was the presenting feature of our case. We attributed this genetic syndrome as an underlying etiology for hypercalcemia after ruling out all the common potential causes of hypercalcemia.
Acknowledgments
The author gratefully acknowledges the department of pediatric genetics for their valuable contribution in the diagnosis and management of our case.
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Research funding: None declared.
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Author contributions: JB: Provided ongoing clinical care, ordered diagnostic workup and coordinated multidisciplinary care, diagnosis and management of the case, data collection, analyzed the data, and drafted the initial manuscript and revisions, submitted the final manuscript. Responded to comments of editor and other reviewers. Drafted the revised manuscript as per the suggestions. BM: Initial patient encounter, assisted in initial diagnostic workup and data collection, and reviewed the manuscript. AA: Assisted in the diagnosis and management, data collection, and reviewed the manuscript. AD: Initial patient encounter, assisted in initial diagnostic workup, initial diagnosis and management, data collection, and reviewed the manuscript. RG: Diagnosis and management of the case, assisted in the data analysis, provided supervision, revised the manuscript, and approved the final manuscript for submission.
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Competing interests: Authors state no conflict of interest.
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Informed consent: Consent obtained from parents of the patient.
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Ethical statement: Research involving human subjects complied with all relevant national regulations, institutional policies and is in accordance with the tenets of the Helsinki Declaration (as revised in 2013), and has been approved by the authors’ Institutional Review Board (xxxx) or equivalent committee. (xxx-Nr.: xx/x). OR The local Institutional Review Board deemed the study exempt from review.
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Supplementary Material
The online version of this article offers supplementary material (https://doi.org/10.1515/jpem-2020-0525).
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