HEC syndrome

Overview

HEC syndrome is a very rare genetic disorder characterized by a triad of symptoms: Hydrocephalus, Endocardial fibroelastosis, and Cataracts - from which the name "HEC" is derived. This condition is typically identified in infancy or early childhood and affects multiple organ systems, particularly the central nervous system, heart, and eyes. Due to its rarity, much of the literature on HEC syndrome comes from isolated case reports, and its clinical course can be severe and life-threatening.

Causes

The exact genetic cause of HEC syndrome remains unclear due to the very limited number of reported cases. However, it is suspected to follow an autosomal recessive pattern of inheritance, meaning both copies of a particular gene must be mutated for the syndrome to manifest. The triad of hydrocephalus, endocardial fibroelastosis, and cataracts suggests a developmental defect that impacts multiple tissues during embryogenesis.

Symptoms

HEC syndrome presents with a characteristic triad, along with possible additional abnormalities:

• Hydrocephalus: Accumulation of cerebrospinal fluid in the brain, leading to increased head size, vomiting, lethargy, and developmental delays.

• Endocardial fibroelastosis: Thickening of the endocardium (inner lining of the heart), which can lead to heart failure, poor feeding, rapid breathing, and cyanosis.

• Cataracts: Clouding of the lens in one or both eyes, which may impair vision from birth or early infancy.

• Other potential findings: developmental delay, hypotonia, seizures, or additional structural abnormalities in the brain or heart.

Diagnosis

Diagnosis of HEC syndrome is typically made based on clinical findings, imaging, and supportive testing:

• Neuroimaging (MRI or CT scan): Confirms hydrocephalus

• Echocardiogram: Detects endocardial fibroelastosis and evaluates cardiac function

• Ophthalmologic examination: Identifies congenital or early-onset cataracts

• Genetic testing: May be performed to look for candidate mutations, although a specific gene has not yet been definitively linked to the syndrome

• Family history: Helps assess potential inheritance patterns, especially in consanguineous families

Treatment

Treatment for HEC syndrome is supportive and focused on managing individual symptoms. It typically involves a multidisciplinary team including neurologists, cardiologists, and ophthalmologists:

• Hydrocephalus: Managed with surgical intervention, typically ventriculoperitoneal (VP) shunting to relieve pressure on the brain

• Cardiac issues: May require medications for heart failure, and in severe cases, heart transplantation

• Cataracts: Surgical removal of cataracts may improve visual outcomes if performed early

• Developmental support: Physical therapy, occupational therapy, and special education may be needed based on developmental delays

Prognosis

The prognosis for individuals with HEC syndrome is generally poor, primarily due to the severity of cardiac and neurological involvement. Many affected infants may not survive beyond early childhood without aggressive and coordinated medical intervention. However, outcomes can vary depending on the severity of symptoms and the timing of treatment. Early diagnosis and multidisciplinary care are essential to managing complications and improving the quality of life for affected individuals and their families.