HDR syndrome is a rare condition with an autosomic dominant inheritance, firstly described in 1977. It is due to a mutation of GATA3 gene, a transcription factor expressed in parathyroid, inner ear, kidney, central nervous system and T lymphocytes. The most common manifestation is neurosensorial deaf, secondary to progressive degeneration of coclear cells. Hypoparathyroidism is present in 90% of patients that can be asymptomatic or, sometimes presents with neuromuscular, cardiac or cognitive symptoms. Kidney manifestions namely renal hypoplasia, renal cysts, tubular acidosis are less common. Other rarer manifestations are neurological and genital malformations, psoriasis and intestinal, cardiac and craniofacial defects. We report the case of a 17 yrs-old boy, who was referred to our Department in May 2018 for hypocalcemia incidentally detected at routine blood tests. The clinical history was unremarkable except for sporadic paresthesia. He successfully played agonistic sport. No cognitive symptoms were present, At physical examination he appeared in good general condition without cleft palate or signs of chronic candidiasis. Trousseau and Chvosteck signs were positive. Biochemical evaluation showed a severe hypocalcemia [albumin–corrected serum calcium 5.3 mg/dl (8.6–10.2) and ionized calcium 0.62 mmol/l (1.13–1.32)], undetectable PTH levels [< 4 pg/ml (8–40)] and normal 25–OH vitamin D level [26.6 µg/l]. He had since age 12 psoriasis treated with topical therapy. Computed tomography displayed multiple cerebral calcifications. Abdomen ultrasound and magnetic resonance imaging showed multiple renal cysts, the largest of which was 6.5 cm. Audiometric examination exhibited a sensorineural hearing loss. No cardiac alterations were detected at ECG and echocardiography. Taking into account the clinical and biochemical data an HDR syndrome was suspected. due to a mutation of GATA3 gene was suspected. Family history was remarkable for hypocalcemic disorders. Genetic analysis of GATA 3 gene in the proband showed a heterozygous mutation in exon 3 (c.404dupC) leading to a frameshift and a truncated protein (p.Ala136GlyfsTer168).The mutation was not identified in the proband parent’s indicating that the mutation was “de novo”. In conclusion, we describe a case of sporadic hypoparathyroidism due to HDR syndrome. This condition, although rare, must be suspected on the basis of clinical evidences and confirmed with genetic analysis. Our patient in on treatment with calcium carbonate and calcitriol, with a good control of serum calcium level and 24 h–urinary calcium excretion.
05 Sep 2020 - 09 Sep 2020