A Case of CATCH22 Syndrome with First Attack of Hypocalcemic Seizure at 13 Years of Age / 소아과

The acronym 'CATCH22' is characterized by many clinical manifestations such as cardiac defects, abnormal face, thymic and parathyroid hypoplasia, cleft palate and hypocalcaemia. It is now known to arise from chromosome 22q11.2 microdeletion, and it is also called 22q11.2 deletion syndrome. Hypocalcemia occurs in more than 50% cases of this syndrome, most frequently in neonatal periods, with some exceptions. Our patient was not diagnosed until age 13, although he had a cleft palate and presented with nasal speech and learning disturbances. He had no clinical manifestations of hypocalcemia until age 13, when he developed generalized tonic-clonic convulsions several times in that year. Laboratory tests showed hypocalcemia, hyperphosphatemia, with normo-to-low parathyroid hormone levels in the serum. Chromosome analysis with FISH revealed a deletion on the proximal portion of the long arm of chromosome 22(22q11.2). The authors herein report a case of CATCH22 syndrome who showed hypocalcemic convulsions in late childhood with a review of the literature.

Clinical Features and Molecular Diagnosis of CATCH-22 Syndrome

BACKGROUND: CATCH-22 syndrome is a common genetic disorder with features of cardiac defect, abnormal face, thymic hypoplasia, cleft palate, and hypocalcemia, along with microdeletion at chromosome 22. This study is to report twelve Korean patients with CATCH-22 syndrome diagnosed by the fluorescent in situ hybridization (FISH) method. METHOD: Clinical features were analyzed according to the FISH result and the Southern blot analysis using new probes DGCR680 and pDH-1 was performed to correlate with the clinical findings and FISH results. Twelve patients were studied by FISH method and eight of them were studied by Southern blot analysis. RESULTS: Seven patients had typical facial features for CATCH-22 syndrome, but five patients had equivocal face, although they were originally suspected to have the conotruncal face. The main cardiac lesion of eight patients were tetralogy of Fallot (TOF) and seven of them had pulmonary atresia. Two cases had other anomalies in the ventricular outflow tract, being common arterial trunk or pulmonary stenosis. Two cases had a patent arterial duct or atrial septal defect (ASD). All of twelve patients had positive result on FISH study. Among eight patients with positive FISH study, six cases were positive for Southern blot analysis. CONCLUSION: We conclude that CATCH-22 syndrome has variable facial, cardiac and genetic features, and the combined use of probes is recommended for a more accurate diagnosis.