Cinacalcet therapy in symptomatic 11-year-old girl with familial hypocalciuric hypercalcemia type 3

Area of Science:

• Genetics
• Endocrinology
• Calcium Metabolism

Background:

• Familial hypocalciuric hypercalcemia type 3 (FHH3) is a rare genetic disorder affecting calcium regulation.
• Pathogenic variants in AP2S1 cause FHH3, which can lead to significant clinical complications.
• Limited data exists on effective treatments for this rare condition.

Purpose of the Study:

• To report a case of FHH3 in a pediatric patient.
• To evaluate the efficacy and tolerability of cinacalcet in treating FHH3.
• To highlight the clinical course and outcomes in a patient with FHH3.

Main Methods:

• A case study of an 11-year-old girl with a de novo heterozygous pathogenic variant in AP2S1.
• Clinical presentation included hypercalcemia, hypocalciuria, elevated parathyroid hormone (PTH), low bone mineral density, and neurodevelopmental difficulties.
• Treatment involved cinacalcet initiation with dose titration and vitamin D3 adjustments.

Main Results:

• Normalization of serum calcium and PTH levels was achieved with cinacalcet therapy.
• Significant improvement in FHH3-related symptoms was observed.
• Despite treatment, lumbar bone mineral density declined, and neurological symptoms persisted.

Conclusions:

• Cinacalcet demonstrates effectiveness and good tolerability as a treatment for FHH3.
• Further research is needed to address unresolved questions regarding skeletal and neurocognitive outcomes in FHH3 patients.
• This case underscores the potential of cinacalcet in managing FHH3 while emphasizing the need for long-term outcome monitoring.