[Striatopallidodentate calcinosis, hypoparathyroidism and neurological features: a case series study]

Pseudohypoparathyroidism type I-b with neurological involvement is associated with a homozygous PTH1R mutation

Pseudohypoparathyroidism type 1b (PHP1b) is characterized by hypocalcemia, hyperphosphatemia, increased levels of circulating parathyroid hormone (PTH), and no skeletal or developmental abnormalities. The goal of this study was to perform a full characterization of a familial case of PHP1b with neurological involvement and to identify the genetic cause of disease. The initial laboratory profile of the proband showed severe hypocalcemia, hyperphosphatemia and normal levels of PTH, which was considered to be compatible with primary hypoparathyroidism. With disease progression the patient developed cognitive disturbance, PTH levels were found to be slightly elevated and a picture of PTH resistance syndrome seemed more probable. The diagnosis of PHP1b was established after the study of family members and blunted urinary cAMP results were obtained in a PTH stimulation test. Integration of whole genome genotyping and exome sequencing data supported this diagnosis by revealing a novel homozygous missense mutation in PTH1R (p.Arg186His) completely segregating with the disease. Here, we demonstrate segregation of a novel mutation in PTH1R with a phenotype of PHP1b presenting with neurological symptoms, but no bone defects. This case represents the extreme end of the spectrum of cognitive impairment in PTH dysfunction and defines a possible novel form of PHP1b resulting from the impaired interaction between PTH and PTH1R.

A Case of Primary Hypoparathyroidism Presenting with Acute Kidney Injury Secondary to Rhabdomyolysis

Hypoparathyroidism is the most common cause of symmetric calcification of the basal ganglia. Herein, a case of primary hypoparathyroidism with severe tetany, rhabdomyolysis, and acute kidney injury is presented. A 26-year-old male was admitted to the emergency clinic with leg pain and cramps, nausea, vomiting, and decreased amount of urine. He had been treated for epilepsy for the last 10 years. He was admitted to the emergency department for leg pain, cramping in the hands and legs, and agitation multiple times within the last six months. He was prescribed antidepressant and antipsychotic medications. He had a blood pressure of 150/90 mmHg, diffuse abdominal tenderness, and abdominal muscle rigidity on physical examination. Pathological laboratory findings were as follows: creatinine, 7.5 mg/dL, calcium, 3.7 mg/dL, alanine transaminase, 4349 U/L, aspartate transaminase, 5237 U/L, creatine phosphokinase, 262.000 U/L, and parathyroid hormone, 0 pg/mL. There were bilateral symmetrical calcifications in basal ganglia and the cerebellum on computerized tomography. He was diagnosed as primary hypoparathyroidism and acute kidney injury secondary to severe rhabdomyolysis. Brain calcifications, although rare, should be considered in dealing with patients with neurological symptoms, symmetrical cranial calcifications, and calcium metabolism abnormalities.

[Seizures revealing phosphocalcic metabolism abnormalities]

Hypocalcemia due to hypoparathyroidism produces a broad spectrum of clinical manifestations, but overt symptoms may be sparse. One unusual presentation is onset or aggravation of epilepsy in adolescence revealing hypoparathyroidism. This situation can lead to delayed diagnosis, with inefficacity of the antiepileptic drugs. We report five cases of adolescence-onset epilepsy with unsuccessful antiepileptic therapy, even with gradually increasing dose. Physical examination revealed signs of hypocalcemia, confirmed biologically. Full testing disclosed the origin of the seizures: hypoparathyroidism in three patients and pseudohypoparathyroidism in the other two. In four of five patients, computed tomography showed calcification of the basal ganglia, defining Fahr's syndrome. The patients were treated with oral calcium and active vitamin D (1-alphahydroxy vitamin D3). Seizure frequency progressively decreased and serum calcium levels returned to normal. These cases illustrate the importance of the physical examination and of routine serum calcium assay in patients with new-onset epileptic seizures in order to detect hypocalcemia secondary to hypoparathyroidism.