# A Rare Presentation of a 12-Year-Old With Systemic Infantile Hyalinosis: A Case Report and Review of the Literature

## TL;DR

A 12-year-old boy with systemic infantile hyalinosis, a rare genetic disorder, was diagnosed through genetic testing and showed an unusual survival beyond typical life expectancy.

## Contribution

This case report documents a rare long-term survival in systemic infantile hyalinosis and confirms the ANTXR2 gene mutation through whole exome sequencing.

## Key findings

- The patient exhibited typical SIH symptoms including joint contractures and hyperpigmented knuckles.
- A homozygous deletion in exon 13 of the ANTXR2 gene was identified through whole exome sequencing.
- The patient's survival beyond typical SIH life expectancy highlights variable disease prognosis.

## Abstract

This case report presents the clinical manifestation and diagnostic testing of a 12-year-old male diagnosed with systemic infantile hyalinosis (SIH) at the Maternity and Children Hospital in Madinah in 2012. The patient presented with typical SIH symptoms, including painful joint contractures, hyperpigmented knuckles, gingival hypertrophy, subcutaneous nodules, and recurrent infections. Whole exome sequencing (WES) analysis identified a homozygous mutation in the ANTXR2 gene, which is a deletion in exon 13 (c.1074delT; p.A359HfsX50), confirming the diagnosis. Notably, this patient's survival beyond the typical age expectancy of SIH, which is usually within the first few years of life, challenges the usual prognosis associated with this disease. This case emphasizes the importance of early diagnosis through clinical suspicion confirmed by genetic analysis and highlights the variability in disease presentation and prognosis.