Case report: Novel homozygous HPGD variant leads to primary hypertrophic osteoarthropathy with intussusception and acro-osteolysis in a Chinese family.

Objective: To perform molecular genetic analysis of a patient diagnosed with primary hypertrophic osteoarthropathy (PHO) with malnourishment, intussusception, and acro-osteolysis. Case presentation: At the age of 7 years, a boy born to a consanguineous couple was diagnosed with PHO attributed to delayed closure of the cranial suture, eczema, clubbing of fingers, and swelling of the knee and ankle. Clinical characteristics and follow-up data for 3 years were collected and analyzed. Trio whole-exome sequencing (WES) and copy number variant sequencing were used to screen for causative genetic variants. Candidate variants of the patient and his parents were confirmed by Sanger sequencing. When he was 7 years old, trio WES found that he had biallelic novel variants c.498 + 1G > A, inherited from his parents, in the Conclusion: PHO due to HPGD defects is rare in pediatric patients, and finding homozygous novel c.498 + 1G > A has expanded the spectrum of causative variants of HPGD and provided a clue for genotype-phenotype correlation analysis. Similar to mouse model results, human HPGD deficiency may also cause abnormal digestive tract development, and related secondary vitamin D deficiency and acro-osteolysis should be considered in HPGD-related PHO.