Hyperphenylalaninemia due to DNAJC12 deficiency

Hyperphenylalaninemia due to DNAJC12 deficiency is a rare inherited condition that affects how the body processes an amino acid called phenylalanine. Amino acids are the building blocks of protein found in food. When the DNAJC12 gene does not work properly, levels of phenylalanine can build up in the blood. This condition is sometimes called DNAJC12-related hyperphenylalaninemia or DNAJC12 deficiency. Unlike the more well-known condition called PKU (phenylketonuria), DNAJC12 deficiency also affects the production of important brain chemicals called neurotransmitters, including dopamine and serotonin. These chemicals help the brain send signals that control movement, mood, and thinking. Because of this, people with DNAJC12 deficiency can experience a range of neurological symptoms, including intellectual disability, movement problems, and behavioral or psychiatric issues, even when phenylalanine levels are only mildly elevated. Babies are often identified through newborn screening programs that check blood phenylalanine levels, but the diagnosis can be missed if doctors do not look for the specific gene change. Treatment usually involves a combination of a low-phenylalanine diet, neurotransmitter replacement therapy using medications like levodopa and 5-hydroxytryptophan, and sometimes a medication called sapropterin (Kuvan), which can help lower phenylalanine levels in some patients. Early diagnosis and treatment are very important because starting therapy early can significantly improve outcomes and quality of life.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

Bring these to your next appointment

• Q1.What phenylalanine level should we be aiming for, and how often should we check it?,Should my child have a spinal fluid test to check neurotransmitter levels, and how will this guide treatment?,Is my child a candidate for sapropterin (Kuvan), and how do we find out?,What are the signs that the levodopa or 5-HTP dose needs to be adjusted?,Are there any clinical trials or research studies we could participate in?,What school or developmental support services should we be asking for?,Should other family members be tested for this condition?

Common questions about Hyperphenylalaninemia due to DNAJC12 deficiency