Related Experiment Video

Updated: Jan 18, 2026

Investigating the Pathogenesis of MYH7 Mutation Gly823Glu in Familial Hypertrophic Cardiomyopathy using a Mouse Model
03:45

Investigating the Pathogenesis of MYH7 Mutation Gly823Glu in Familial Hypertrophic Cardiomyopathy using a Mouse Model

Published on: August 8, 2022

4.2K

Familial hypocalciuric hypercalcaemia type 1 due to a rare CASR missense mutation: a delayed diagnosis in a man with

Hsu Yee Mon1, Nwe Ni Win1, Samson Oghenetsovwe Oyibo2

  • 1Medicine, North West Anglia NHS Foundation Trust, Peterborough, Cambridgeshire, UK.

BMJ Case Reports
|September 10, 2025
PubMed

Insights

Familial hypocalciuric hypercalcaemia (FHH) is a rare cause of high calcium levels. Genetic testing confirmed FHH in a patient initially suspected of primary hyperparathyroidism, highlighting diagnostic challenges.

Area of Science:

  • Endocrinology
  • Genetics
  • Nephrology

Background:

  • Familial hypocalciuric hypercalcaemia (FHH) is a rare genetic disorder.
  • It is an important consideration in the differential diagnosis of hypercalcaemia.
  • Distinguishing FHH from primary hyperparathyroidism (PHPT) can be challenging.

Purpose of the Study:

  • To describe a case of FHH initially misdiagnosed as PHPT.
  • To highlight the diagnostic difficulties in differentiating FHH and PHPT.
  • To emphasize the role of genetic testing in diagnosing FHH.

Main Methods:

  • Case report of a man in his 60s with persistent hypercalcaemia.
  • Initial evaluation included serum parathyroid hormone (PTH) levels, 24-hour urinary calcium excretion, bone density, and kidney imaging.
  • Subsequent evaluation involved repeat PTH and urinary calcium measurements, calcium-creatinine clearance ratio, and genetic testing for FHH.

Main Results:

  • The patient presented with hypercalcaemia, normal PTH, normal 24-hour urinary calcium, and normal imaging, consistent with FHH.
  • Genetic testing revealed a rare mutation in the calcium-sensing receptor gene, confirming FHH type 1.
  • A low calcium-creatinine clearance ratio was a key indicator for genetic testing.

Conclusions:

  • This case underscores the importance of considering FHH in the differential diagnosis of hypercalcaemia.
  • The calcium-creatinine clearance ratio can aid in differentiating FHH from PHPT.
  • Genetic testing is crucial for definitive diagnosis of FHH, especially in ambiguous cases.

Keywords:
Calcium and boneGeneticsHypophosphatemia

More Related Videos

Targeted Next-generation Sequencing and Bioinformatics Pipeline to Evaluate Genetic Determinants of Constitutional Disease09:34

Targeted Next-generation Sequencing and Bioinformatics Pipeline to Evaluate Genetic Determinants of Constitutional Disease

Published on: April 4, 2018

34.6K
Calcification of Vascular Smooth Muscle Cells and Imaging of Aortic Calcification and Inflammation08:43

Calcification of Vascular Smooth Muscle Cells and Imaging of Aortic Calcification and Inflammation

Published on: May 31, 2016

20.2K

Related Concept Videos

Urinary Tract Calculi I: Introduction01:28

Urinary Tract Calculi I: Introduction

Renal calculi, or kidney stones, are solid deposits of minerals and salts formed inside the kidneys. In medical terminology, "calculus" refers to the stone itself, while "lithiasis" describes the process of stone formation. Depending on their location within the urinary system, these stones may be classified as either urolithiasis, when situated within the urinary tract, or nephrolithiasis, when located within the kidneys. Each term signifies the specific impact of the stone.Predisposition...
415
Inborn Errors of Metabolism01:20

Inborn Errors of Metabolism

Phenylketonuria (PKU) is a protein metabolism disorder characterized by high blood levels of the amino acid phenylalanine. This results from a mutation in the gene responsible for phenylalanine hydroxylase, an enzyme that converts phenylalanine into tyrosine. When this enzyme is deficient, phenylalanine builds up in the blood, leading to symptoms such as vomiting, rashes, seizures, growth deficiency, and severe mental retardation. An early diagnosis and a diet restricting phenylalanine intake...
699
Cystic Fibrosis: Pathogenesis01:23

Cystic Fibrosis: Pathogenesis

Cystic fibrosis (CF), an autosomal recessive disorder, significantly affects the function of exocrine glands. This genetically inherited disease is characterized by the production of thick and sticky mucus, which can severely affect various organs and systems in the body.
CF is primarily caused by a genetic mutation in a chromosome 7 gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The most common gene mutation leading to CF is the ΔF508 mutation,...
730
Urinary Tract Calculi II: Pathophysiology and Clinical Manifestations01:26

Urinary Tract Calculi II: Pathophysiology and Clinical Manifestations

Renal calculi, commonly termed kidney stones, are crystalline solid masses that form in the kidneys but can occur at any point within the urinary system, encompassing the kidneys, ureters, bladder, and urethra.The pathophysiology of renal stones involves several key factors: supersaturation of the urine with stone-forming constituents, changes in urine pH, a decrease in urine volume, and the presence of substances that promote or inhibit stone formation.Supersaturation of Urine: This is the...
375
Mutations01:39

Mutations

Overview
94.4K
Cardiomyopathy III: Hypertrophic Cardiomyopathy01:29

Cardiomyopathy III: Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy, or HCM, is an autosomal dominant genetic disorder characterized by asymmetric left ventricular hypertrophy without ventricular dilation. It is more common in men and is typically diagnosed in young, athletic adults.EtiologyHCM is primarily genetic and is caused by mutations in genes encoding sarcomeric proteins. Researchers have identified over 1400 mutations across at least 11 different genes. Among these, the most frequently occurring mutations are found in the...
416