Monogenic diabetes is a rare cause of diabetes in the population, accounting for an estimated 1–5% of diabetes cases. Variants in the hepatocyte nuclear factor 1 beta (
HNF1B) gene represent approximately 1–6% of monogenic diabetes causes [
1]. The
HNF1B gene, located on chromosome 17q12, plays a fundamental role in organogenesis, primarily of the kidney, pancreas, liver, and genitourinary system. Pathogenic variants of
HNF1B are diverse and include intragenic alterations, insertions, and deletions affecting only parts of the gene, among others. However, the most common occurrence, present in about half of the patients, is microdeletions on chromosome 17q12 that affect the entire gene and include neighboring genes (e.g.,
ACACA and
LHX1) [
2].
HNF1B haploinsufficiency leads to a diverse and highly variable clinical phenotype spectrum, potentially leading to renal cysts and diabetes syndrome (RCAD) and, when associated with neuropsychiatric abnormalities, 17q12 deletion syndrome. The most common clinical manifestation involves structural renal anomalies, observed in 90% of cases (most frequently renal cysts), with chronic kidney disease developing in approximately 50% of patients. Among extrarenal manifestations, diabetes is the most frequent (50–80%), with an average diagnosis age of 24 years, followed by genitourinary tract malformations, hypomagnesemia, hyperuricemia, and altered liver profiles, among others [
3,
4]. …
