Case Report: Identification of a HNF1A exons 1–10 heterozygous deletion in a Chinese MODY family

This study identifies a <i>HNF1A</i> whole-gene deletion in a Chinese family with MODY, confirming the effectiveness of sulfonylureas for HNF1A-MODY management. Large <i>HNF1A</i> deletions, undetectable by standard sequencing, can cause MODY and necessitate copy number variant (CNV) analysis. MLPA is essential for definitive MODY diagnosis, particularly in cases with strong clinical suspicion but negative sequencing results. These findings broaden the known spectrum of <i>HNF1A</i> mutations and highlight the critical role of CNV detection in MODY genetic testing.