Hypoparathyroidism as the major manifestation in two patients with 22q11 deletions

Abstract

We report on two adolescents with 22q11 deletion. Their main clinical manifestation was chronic symptomatic hypocalcemia secondary to hypoparathyroidism, together with seizures and cerebral calcifications. Neither congenital cardiac abnormality nor T cell deficiency were detected. The phenotypic manifestations of the observed patients were consistent with velo-cardio-facial syndrome (VCFS). A microdeletion of chromosome region 22q11 has been demonstrated in approximately 90% of DiGeorge syndrome (DGS) patients and in 75% of VCFS patients; the association of the deletion with a wide spectrum of clinical findings suggests the existence of a contiguous gene syndrome. The presence of certain traits of DGS/VCFS should lead to investigations of the parathyroid function and molecular analysis of the 22q11 region hybridization studies.

Parathyroid Gland Dysfunction in 22q11.2 Deletion Syndrome

“…The 22q11.2 deletion syndrome (22q11DS) is a genetic disorder with an estimated prevalence of approximately 1 per 4,000 live births [1,2,3,4,5,6,7]. The phenotypic features include conotruncal cardiac defects, hypoparathyroidism (HPT), minor facial anomalies, and immune deficiency [1, 8].…”

“…Patients presenting with only mild facial anomalies [1] or with unusual hormone deficiencies (growth hormone deficiency, hypo- or hyperthyroidism) [9, 11] have also been described. While the etiology of these syndromes is heterogeneous, the microdeletion of chromosome 22q11.2 is found by fluorescence in situ hybridization (FISH) in up to 90% of patients with DGS and in 75% of patients with VCFS [4]. …”

“…Various forms of HPT in patients with 22q11DS have been reported. These include late onset [5, 9, 13], transient [9, 14, 15], latent [4, 8, 9, 16], and recurrent HPT [17]. However, the evolution over time of parathyroid gland dysfunction in 22q11DS is less well-characterized than its other manifestations.…”

DiGeorge Syndrome with Graves' Disease. A Case Report.

“…It also affects other portions of the pharyngeal pouch besides the third and fourth pharyngeal pouch, and abnormal migration of neural crest cells is thought to be the cause of this anomalies [l, 2]. More than 95% of the subjects reveal the deletion by translocation of the 22nd chromosome long arm q 11 [3][4][5][6][7][8][9][10][11][12][13][14][15] . The initial symptom is tetany due to hypocalcemia within 24-48 hours after birth, with symptoms associated with immune defects appearing later.…”

Deletion 22q11

“…1 It causes a spectrum of well-described clinical syndromes, which includes DiGeorge syndrome (conotruncal heart defect, hypocalcemia, and thymic hypoplasia) 2 ; velocardiofacial syndrome (VCFS) (cleft palate or velopharyngeal insufficiency, hypernasal speech, learning disabilities, heart defects, and characteristic facial findings) 2 ; and conotruncal anomaly face syndrome (conotruncal heart defects and typical facial appearance). 3 Chromosome 22q11 deletion has been found in 11% to 16% of cases of nonsyndromic congenital conotruncal heart disease, 4,5 and has been reported to present as apparently isolated neonatal hypocalcemia 6,7 or learning problems. 8 Furthermore, some individuals manifest only mild facial abnormalities.…”