Novel Compound Heterozygous Mutations of the SLC12A3 Gene in Gitelman Syndrome with Growth Hormone Deficiency and Hypothyroidism

Introduction: Gitelman syndrome (GS) is an inherited kidney disease that causes an imbalance of charged ions in the body. SLC12A3 mutation is the predominant cause of GS. There are different known and unknown pathogenic mutations in SLC12A3. Case Presentation: In the present case report, an 8-year-old girl was referred to our pediatric endocrinology clinic for evaluation of short stature. Her height was 113 cm (-2.94 SD). Her growth hormone peak was 5.81 ng/mL. IGF-1 was lower than -2SD. Thyroid stimulating hormone was high. The blood potassium was 3.37 mmol/L. After 3 months of GH treatment, her blood potassium dropped further (3.01 mmol/L). The gene test results showed that there were two heterozygous mutations of the SLC12A3 gene: C.1456G >A (p.D486N) and c.1065 1072 delGCAGGG (p.A356Qfs*5), which her parents verified. Conclusions: Gitelman syndrome can be associated with growth hormone deficiency and hypothyroidism in addition to short stature, hypokalemia, and hypomagnesemia, and the underlying molecular mechanisms need to be explored in the coexistence of these three diseases. The experience, in this case, is that blood electrolytes should be checked monthly for the first three months after growth hormone treatment for short stature. Once the blood potassium level is low, much attention should be paid to further diagnosis to avoid misdiagnosis.