An Introduction to Hallermann-Streiff Syndrome

Hearing that your child has a condition as rare as Hallermann-Streiff Syndrome (HSS) can feel incredibly isolating. Because there are only about 200 documented cases worldwide, you may find that many doctors you encounter have never treated a patient with HSS before ^[1][2]. This guide is designed to help you understand the basics of the syndrome and prepare you for the specialized care your child will receive.

Understanding HSS

Hallermann-Streiff Syndrome is a rare congenital condition—meaning it is present at birth—that primarily affects the growth of the skull, face, and eyes. While the exact genetic cause is still being researched and is often described as a “missing molecular link,” the diagnosis is usually made by doctors recognizing a specific set of physical features ^[3][4].

Despite the significant physical challenges affecting the skull and face, it is highly reassuring to know that children with Hallermann-Streiff Syndrome typically have normal intelligence and cognitive development ^[3].

Common Features of HSS

Doctors look for several “cardinal” features to identify HSS. Your child may have some or all of the following:

• Distinctive Facial Structure: A small, thin, or “bird-like” nose and a significantly small lower jaw (micrognathia) ^[5][3].
• Skull Shape: A head that may appear shorter or wider than average (brachycephaly), sometimes with a prominent forehead ^[5].
• Eye Characteristics: Unusually small eyes (microphthalmia) and the presence of congenital cataracts (clouding of the lens of the eye) at birth ^[5][6].
• Dental Anomalies: Teeth that may be present at birth (natal teeth) or teeth that are missing or unusually shaped later in life ^[7][8].
• Skin and Hair: Thinning hair (hypotrichosis) and skin that may appear thin or tight, especially on the face ^[5][9].

Immediate Priorities for Your Infant

In the first days and weeks of life, the medical team will focus on two critical areas: breathing and feeding.

Protecting the Airway

Because the lower jaw in babies with HSS is often very small, the tongue can fall back and block the airway. This can lead to obstructive sleep apnea (OSA), where breathing stops and starts during sleep ^[10].

• Monitoring: Your baby may need a sleep study (polysomnogram) to check for breathing issues ^[10].
• Intervention: Some infants may need support from non-invasive ventilation (like a CPAP machine) or, in more severe cases, a procedure to gently lengthen the jaw to create more room for breathing.

Supporting Nutrition

The same jaw and airway challenges that affect breathing can also make feeding difficult. For a baby with severe airway issues and a tiny jaw, the risk of aspiration (inhaling fluid into the lungs) is high. While specialized bottles can help some, many infants require a feeding tube (such as an NG-tube through the nose or a surgically placed G-tube in the stomach) to survive and grow safely without the exhaustion of trying to suck and swallow ^[11][12]. This is a normal, life-saving necessity for many children with HSS.

What’s Next

Because HSS affects multiple parts of the body, your child will benefit from a multidisciplinary team. The following pages will dive deeper into your child’s specific needs and provide you with actionable steps:

While the early months can be filled with many appointments and intensive monitoring, children with HSS can grow, learn, and lead fulfilling lives. As the “expert” on your child, you are the most important member of this care team.