Noonan syndrome: Clinical and molecular profile with review of literature

Abstract

Background: Noonan syndrome is a rare genetic disorder, characterized by dysmorphic facies, short stature, congenital heart diseases, and delay in development of variable degree. Aims: The aim of this study was to highlight the clinical spectrum, molecular profile, and outcome of Noonan syndrome patients from India. Settings and Design: A retrospective observational study was carried out between 2017 and 2020 in our tertiary care teaching institute. Materials and Methods: The retrospective data of consecutive patients were collected including clinical profile, investigations, and molecular analysis. Results: There were seven pediatric patients with Noonan syndrome. Characteristic facies, broad nose, low-set ears, short stature, and congenital cardiac anomalies (pulmonary stenosis) were present in all 7/7 (100%) patients. Short neck was present in 6 (85.71%), depressed nasal bridge in 5 (71.43%), development was grossly delayed in 5 (71.43%), and chest wall deformities in 4 (57.14%) patients. Cryptorchidism was present in 5 out of 6 (83.33%) male patients. Mutation in protein-tyrosine phosphatase nonreceptor type 11 gene was detected in all 4 out of 7 (57.14%) patients in whom genetic study was performed. Conclusions: A high index of suspicion for Noonan syndrome should be kept in mind in a patient presenting with facial dysmorphism, short stature, and congenital heart diseases with genitourinary abnormalities including cryptorchidism. A proper health education and counseling to the parents about the problem and alternative methods for having a healthy baby should be emphasized. Molecular confirmation is essential for prenatal diagnosis.

Keywords

• autosomal dominant
• cryptorchidism
• noonan syndrome
• protein-tyrosine phosphatase nonreceptor type 11 mutation