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Magnesium is essential for the functioning and release of parathyroid hormone. Therefore, its deficiency can present as functional hypoparathyroidism. This case report describes a rare inherited disorder called congenital hypomagnesaemia with secondary hypocalcaemia due to TRPM6 gene mutation. This disease clinically and biochemically mimics hypoparathyroidism. However, unlike hypoparathyroidism, it can be treated only by long-term oral magnesium supplements. The patient presented to us with recurrent hypocalcaemic convulsions. The laboratory picture in each admission was similar to that of hypoparathyroidism. However, the hypocalcaemia persisted, and it was noticed to be associated with persistent hypomagnesaemia. A defect in the tubular magnesium reabsorption was postulated and a genetic analysis of the patient was done, which revealed a TRPM6 mutation causing hypomagnesaemia by excessive renal excretion of magnesium. The child responded well to oral magnesium supplements and is currently developmentally appropriate for her age and thriving well., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Hypocalcaemia is a frequently encountered electrolyte abnormality in neonates and it is mostly transient. However, persistent hypocalcaemia can point towards an endocrine abnormality like hypoparathyroidism, which is usually due to genetic disorders like DiGeorge and Kearns Sayre syndrome or due to mutations of genes like GCM2, CaSR and PTH.Our patient was a female child, who presented with hypocalcaemic convulsions in the neonatal period. On laboratory assessment, serum phosphate levels were noted to be high along with inappropriately low parathyroid hormone (PTH) levels. The child was diagnosed to have hypoparathyroidism and was started on oral calcium and 1,25-dihydroxycholecalciferol supplements to which she responded well. However, the child was lost to follow-up and was readmitted with hypocalcaemic convulsions in infancy. Clinical exome analysis done was diagnostic of homozygous PTH gene mutation. This case demonstrates a rare form of congenital isolated hypoparathyroidism with no other syndromic associations., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2023. No commercial re-use. See rights and permissions. Published by BMJ.)

Genetic causes of hypocalcaemia can be overlooked in patients who present without apparent syndromic features. One relatively common but under-recognised genetic disorder is DiGeorge syndrome, which is often diagnosed in childhood but rarely in adulthood. Its enigmatic diagnosis can be attributed to its broad heterogeneous clinical presentation, such as the absence of cardiac abnormalities with only subtly abnormal facies. The presence of hypoparathyroidism-related hypocalcaemia may be the first early sign. We describe a young female adult with childhood-onset hypocalcaemia who was diagnosed with DiGeorge syndrome during her pregnancy when the fetus was found to have the same condition on antenatal screening and autopsy. This case reminds clinicians to consider the genetic causes of hypoparathyroidism-induced hypocalcaemia early on in childhood, while acknowledging the possibility of a late diagnosis in adulthood. We also highlight the risks of severe hypocalcaemia in pregnancy and outline a systematic approach to the evaluation of chronic hypocalcaemia., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

A 58-year-old male patient was admitted at the São Bernardos's Hospital (Setúbal, Portugal) with generalised muscle spasms, dyspnoea, laryngospasm and bronchospasm in the context of severe hypocalcaemia. Despite efforts to correct serum calcium, it remained below average, leading to question the true cause of hypocalcaemia. Low parathyroid hormone and 25-hydroxyvitamin D, along with facial anomalies, palate defect and cognitive impairment with concomitant psychiatric disorder led to a suspicion of a DiGeorge/velocardiofacial/22q11.2 deletion syndrome (DS), which was confirmed through genetic testing. The 22q11.2 DS has a wide phenotypic expression and there are growing reports of diagnosis being made in adulthood. This case report highlights the importance of understanding the cause of refractory hypocalcaemia and alerts medical community to carefully access these patients, for this metabolic disorder may only present in later stages of life., Competing Interests: Competing interests: None delcared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

A growing amount of evidence indicates that 22q11.2 deletion syndrome (22q11.2DS) increases the risk of early-onset Parkinson's disease (EOPD). Here, we describe a 36-year-old patient with EOPD. The patient presented with 22q11.2DS features, including associated cognitive disabilities, hypocalcaemia and facial dysmorphia that led us to screen for and confirm this deletion. In addition, hypocalcaemia and vitamin D deficiency were the main factors responsible for severe, painful muscle spasms that were non-levodopa (L-Dopa) responsive and remitted after calcium and vitamin D replacement therapy. Many patients with this deletion remain undiagnosed until adulthood due to the absence of 'major' phenotypic hallmarks, which usually present during early childhood. Later onset problems involving various medical subspecialties are increasingly recognised as important components of 22q11.2DS. Therefore, the multisystem nature and associated burden of morbidities demand a high degree of suspicion for this entity from all clinicians regardless of their medical subspecialty., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Magnesium is the second most abundant intracellular cation and plays an essential role in neuronal, skeletal and cardiac tissue. Hypomagnesaemia can cause hypocalcaemia by inhibiting parathyroid hormone release and inducing resistance at its receptor sites. Untreated hypomagnesaemia can lead to tetany, recurrent seizures, status epilepticus and life-threatening arrhythmias. Primary hypomagnesaemia with secondary hypocalcaemia (HSH) is a rare metabolic disorder of intestinal magnesium absorption. The condition typically presents in the neonatal period with neuromuscular excitability and seizures refractory to antiepileptic therapy. Early diagnosis and prompt magnesium replacement are essential to prevent death or long-term neurodevelopmental sequelae. Fewer than a hundred cases are reported in the literature. Recent advances have added significantly to our understanding of the genetic basis of HSH. We report the presentation and long-term follow-up of an affected female who was found to have a mutation in the transient receptor potential melastatin 6 (TRPM6) gene, encoding a transient receptor potential cation channel., (2016 BMJ Publishing Group Ltd.)

Patients with chromosome 22q11.2 deletion syndrome (22q11.2DS) exhibit various combinations of signs and symptoms including facial dysmorphism, thymus absence, hypoparathyroidism, cellular immunodeficiency and cardiac abnormalities caused by microdeletion of chromosome 22q11.2. Most cases are diagnosed during post-natal cardiac evaluation, though some are diagnosed at later stages. We report the case of a 39-year-old man with 22q11.2DS presenting with seizure due to tardily manifested hypocalcaemia and anxiety disorder. Our experience suggests that 22q11.2DS patients lacking fatal or well-recognised manifestations such as cardiac defects, immunodeficiency and facial dysmorphism tend to survive without medical attention, and are therefore overlooked. Recognition of the age-related variance of the manifestations, and specifically of tardily manifested hypocalcaemia and psychiatric or developmental disorders as manifestations of 22q11.2DS in adulthood, is important for diagnosis and can also help us provide appropriate medical and psychosocial support for newly diagnosed 22q11.2DS patients in adolescence or adulthood and their families., (2015 BMJ Publishing Group Ltd.)

Stridor in older children can be due to diverse aetiology that includes infections, anaphylaxis and rarely systemic conditions leading to hypocalcaemia. We report the case of a previously asymptomatic 11-year-old girl who presented to the casualty with stridor due to hypocalcaemia. The aetiological investigations for hypocalcaemia uncovered previously undetected chronic renal failure, possibly due to a rare autosomal recessive condition called nephronophthisis. We report this case to highlight the importance of widening the diagnostic focus for children presenting with stridor, especially when they fall outside the usual age group for infections like croup, or when the history is atypical.