MedGen

A behavioral or psychological symptom that typically occurs following exposure to one or more traumatic events is posttraumatic stress disorder (PTSD). Symptoms of PTSD include intrusive recollections, such as re-experiencing the trauma through flashbacks, memories, or nightmares. Additionally, individuals may experience avoidant and numbing symptoms, which can include diminished emotions and avoidance of situations that serve as reminders of the traumatic event. Hyperarousal is another symptom, characterized by increased irritability, exaggerated startle reactions, and difficulties with sleeping or concentrating. [from HPO]

Tetrahydrobiopterin (BH4)-deficient hyperphenylalaninemia (HPA) comprises a genetically heterogeneous group of progressive neurologic disorders caused by autosomal recessive mutations in the genes encoding enzymes involved in the synthesis or regeneration of BH4. BH4 is a cofactor for phenylalanine hydroxylase (PAH; 612349), tyrosine hydroxylase (TH; 191290) and tryptophan hydroxylase (TPH1; 191060), the latter 2 of which are involved in neurotransmitter synthesis. The BH4-deficient HPAs are characterized phenotypically by hyperphenylalaninemia, depletion of the neurotransmitters dopamine and serotonin, and progressive cognitive and motor deficits (Dudesek et al., 2001). HPABH4A, caused by mutations in the PTS gene, represents the most common cause of BH4-deficient hyperphenylalaninemia (Dudesek et al., 2001). Other forms of BH4-deficient HPA include HPABH4B (233910), caused by mutation in the GCH1 gene (600225), HPABH4C (261630), caused by mutation in the QDPR gene (612676), and HPABH4D (264070), caused by mutation in the PCBD1 gene (126090). Niederwieser et al. (1982) noted that about 1 to 3% of patients with hyperphenylalaninemia have one of these BH4-deficient forms. These disorders are clinically and genetically distinct from classic phenylketonuria (PKU; 261600), caused by mutation in the PAH gene. Two additional disorders associated with BH4 deficiency and neurologic symptoms do not have overt hyperphenylalaninemia as a feature: dopa-responsive dystonia (612716), caused by mutation in the SPR gene (182125), and autosomal dominant dopa-responsive dystonia (DYT5; 128230), caused by mutation in the GCH1 gene. Patients with these disorders may develop hyperphenylalaninemia when stressed. [from OMIM]

An anxiety disorder precipitated by an experience of intense fear or horror while exposed to a traumatic (especially life-threatening) event. The disorder is characterized by intrusive recurring thoughts or images of the traumatic event; avoidance of anything associated with the event; a state of hyperarousal and diminished emotional responsiveness. These symptoms are present for at least one month and the disorder is usually long-term. [from NCI]