PACS-1 related syndrome causes intellectual disability, developmental delay, and distinctive facial features. This condition is present from birth. Symptoms of PACS-1 related syndrome may include low muscle tone, feeding difficulties, constipation, seizures, and heart defects. PACS1-related syndrome is caused by a specific genetic variant in the PACS1 gene. In most cases, this gene variant is not inherited, but occurs as a new change during the making of the egg or the sperm. The diagnosis is based on the symptoms, a clinical examination, and may be confirmed by the results of genetic testing. As of 2017, less than 70 people have been diagnosed with this syndrome. Treatment for PACS1-related syndrome is focused on managing the symptoms and may include medications to prevent seizures and placement of a feeding tube to help with weight gain.

Signs and symptoms of PACS1-related syndrome may include:

• Intellectual disability
• Developmental delay
• Low muscle tone (hypotonia)
• Feeding difficulties
• Seizures
• Behavioral features
• Distinctive facial features
• Heart defects

Children with PACS1-related syndrome often have facial features that make them look similar to each other. These features can include low hairline, low set ears, wide spaced eyes, and a round nasal tip. Some boys with PACS1-related syndrome may have undescended testes (cryptorchidism). Less than 70 cases of PACS1-related syndrome have been reported in the medical literature, and little is known about how this condition changes over time.

PACS1 gene is not working correctly. DNA changes known as pathogenic variants are responsible for making genes work incorrectly or sometimes, not at all.

PACS1 gene in either the egg or sperm. Neither parent has the genetic variant, and the chance for them to have another child with PACS1-related syndrome is less than 1%.

Diagnosis of PACS1-related syndrome is based on the symptoms, a clinical examination, and may confirmed by the results of genetic testing. Other conditions may need to be ruled out before PACS1-related syndrome is diagnosed.

Specialists involved in the care of someone with PACS1-related syndrome may include:

• Neurologist
• Gastroenterologist
• Cardiologist
• Ophthalmologist
• Developmental specialist
• Physical and/or occupational therapist
• Medical geneticist

Because PACS1-related syndrome is so rare, there is not a lot of information about the long-term outlook for children and adults with the syndrome. PACS1-related syndrome is not known to shorten a person’s lifespan. People with PACS1-related syndrome will likely need extra help in school, such as special education classes. They will also need to be monitored throughout their lives to make sure they do not develop any additional health issues.