Overgrowth syndromes are genetic conditions characterized by a generalized or localized increase in tissue.
Beckwith-Wiedemann Syndrome (BWS)
- Pathophysiology: Imprinting defect on chr 11p15.5 (maternal methylation loss, paternal UPD) deregulation of imprinted growth genes (IGF2, CDKN1C) somatic overgrowth.
- Clinical Features:
- Macrosomia & hemihyperplasia (asymmetric limb/body growth).
- Macroglossia (leads to airway obstruction and feeding difficulty).
- Omphalocele or umbilical hernia.
- Neonatal hypoglycemia (islet-cell hyperplasia hyperinsulinism).
- Earlobe creases, posterior helical pits, visceromegaly.
- Diagnosis:
- Initial: Clinical presentation + blood glucose monitoring.
- Confirmatory: Genetic testing (methylation analysis/MLPA of 11p15.5).
- Management:
- Hypoglycemia: Immediate feeds; IV D10W if refractory.
- Surgical: Omphalocele repair, reduction glossectomy (if airway/speech compromised).
- Tumor Surveillance:
- Abdominal US every 3 months until age 7 (screens for Wilms tumor and hepatoblastoma). c
- Serum AFP every 3 months until age 4 (screens for hepatoblastoma).
- Key Differentials:
- Sotos syndrome: Overgrowth with macrocephaly, intellectual disability, long face; no hypoglycemia.
- Congenital hypothyroidism: Macroglossia and umbilical hernia; differentiated by lethargy, hypotonia, and ↑ TSH.