Identification of TBX5 mutations in a series of 94 patients with Tetralogy of Fallot.

Tetralogy of Fallot (TOF) (OMIM #187500) is the most frequent conotruncal congenital heart defect (CHD) with a range of intra- and extracardiac phenotypes. TBX5 is a transcription factor with well-defined roles in heart and forelimb development, and mutations in TBX5 are associated with Holt-Oram syndrome (HOS) (OMIM#142900). Here we report on the screening of 94 TOF patients for mutations in TBX5, NKX2.5 and GATA4 genes. We identified two heterozygous mutations in TBX5. One mutation was detected in a Moroccan patient with TOF, a large ostium secundum atrial septal defect and complete atrioventricular block, and features of HOS including bilateral triphalangeal thumbs and fifth finger clinodactyly. This patient carried a previously described de novo, stop codon mutation (p.R279X) located in exon 8 causing a premature truncated protein. In a second patient from Italy with TOF, ostium secundum atrial septal defect and progressive arrhythmic changes on ECG, we identified a maternally inherited novel mutation in exon 9, which caused a substitution of a serine with a leucine at amino acid position 372 (p.S372L, c.1115C>T). The mother's clinical evaluation demonstrated frequent ventricular extrasystoles and an atrial septal aneurysm. Physical examination and radiographs of the hands showed no apparent skeletal defects in either child or mother. Molecular evaluation of the p.S372L mutation demonstrated a gain-of-function phenotype. We also review the literature on the co-occurrence of TOF and HOS, highlighting its relevance. This is the first systematic screening for TBX5 mutations in TOF patients which detected mutations in two of 94 (2.1%) patients.

The use of propranolol for complicated infantile hemangiomas.

OBJECTIVE: To assess propranolol efficacy and safety in complicated infantile hemangiomas in two different age groups. PATIENTS AND METHODS: We report on 68 infants with infantile hemangiomas treated with oral propranolol at the lowest effective dose at different ages for a period of six months. Inclusion criteria were life-threatening hemangiomas, function-threatening hemangiomas, facial hemangiomas with risk for disfigurement, and extensive and ulcerated hemangiomas. A previously designed safety protocol was applied to all patients. The evolution of all hemangiomas since baseline (pre-therapy) until the end of follow-up was assessed on the basis of clinical features (color, palpable softening, size, and volume) and taken at follow-up visits. RESULTS: Our results showed that propranolol was effective in arresting the proliferative phase and in accelerating the involution of infantile hemangiomas in 92.6% of cases. Propranolol efficacy was clear even when it was started after 12 months of life at low dose; after discontinuation of therapy there was a moderate-to-severe regrowth in 9.3% of cases and a mild regrowth in 22.5%. No adverse events were observed. CONCLUSIONS: Propranolol should be used as first-line medical treatment in all cases of complicated infantile hemangiomas.

Genetic heterogeneity and phenotypic anomalies in children with atrioventricular canal defect and tetralogy of Fallot.

Tetralogy of Fallot associated with the atrioventricular canal defect has been usually reported in association with Down syndrome. The aim of the present study was to describe the cardiac aspects and the genetic anomalies in children with this association of heart defects. We identified 64 patients with atrioventricular canal defect tetralogy of Fallot. All children underwent complete cardiovascular, clinical phenotypic and genetic evaluation. A genetic syndrome or extracardiac anomalies were found in 56 patients (87.5%). Down syndrome (43 patients, 67.2%) was the most frequent genetic diagnosis. Other syndromes were 8p deletion, trisomy 13, duplication 5p, cranio-cerebello-cardiac syndrome, Cantrell syndrome, CHARGE association, VACTERL association, and DiGeorge syndrome related to maternal diabetes. No patients in our series had 22q11 deletion. Tetralogy of Fallot with extreme dextroposition of the aorta was found in seven patients (only one with Down syndrome). Additional cardiac malformations were present in 23 patients (only 11 with Down syndrome). The association between atrioventricular canal defect and tetralogy of Fallot represents a cardiac phenotype with strong genetic characteristics. For this reason, a careful genetic examination is required. Our study confirms the high prevalence of Down syndrome, but also reveals a significant genetic heterogeneity. Additional cardiac defects are prevalent in patients without Down syndrome.