Noonan syndrome-like disorder with loose anagen hair

Noonan syndrome-like disorder with loose anagen hair (also known as Mazzanti syndrome or Noonan-like syndrome with loose anagen hair) is a rare genetic condition that shares many features with classic Noonan syndrome but is distinguished by a characteristic hair abnormality known as loose anagen hair. In this hair condition, hairs can be easily and painlessly pulled from the scalp because they are poorly anchored during the growth (anagen) phase. The disorder is primarily caused by mutations in the SHOC2 gene, which plays a role in the RAS-MAPK signaling pathway. The condition affects multiple body systems. Key clinical features include distinctive facial characteristics (such as a broad forehead, hypertelorism, downslanting palpebral fissures, and low-set posteriorly rotated ears), short stature, congenital heart defects (particularly pulmonary valve stenosis, septal defects, and hypertrophic cardiomyopathy), ectodermal abnormalities (sparse, thin, slow-growing hair with the loose anagen hair phenotype, as well as darkly pigmented skin with eczema-like features), and cognitive delays ranging from mild to moderate intellectual disability. Macrocephaly, a short neck with redundant skin folds, and a distinctive voice may also be present. Growth hormone deficiency has been reported in some patients. There is no cure for this condition, and management is supportive and symptom-based. Treatment may include cardiac monitoring and surgical intervention for heart defects, growth hormone therapy for short stature when growth hormone deficiency is documented, developmental support and early intervention services for cognitive delays, and dermatologic care for skin and hair abnormalities. Regular multidisciplinary follow-up with cardiology, endocrinology, and developmental specialists is recommended to optimize outcomes.

Common questions about Noonan syndrome-like disorder with loose anagen hair