Type I Nonketotic Hyperglycinemia (NKH) is a rare genetic disorder characterized by the accumulation of the amino acid glycine in the body. It is considered an autosomal recessive disorder, meaning that it is inherited from both parents who each carry a copy of the affected gene.
NKH typically manifests in infancy and affects the central nervous system, leading to impaired brain development and function. Symptoms may include seizures, lethargy, weak muscle tone, and difficulty feeding. Newborns with this condition may also experience respiratory problems and exhibit a distinctive high-pitched cry.
The elevated levels of glycine in NKH occur due to a deficiency or malfunction of the enzyme known as glycine cleavage system, which is responsible for breaking down glycine. The build-up of glycine in the brain disrupts normal neurotransmission, leading to neurological impairment.
Diagnosis of NKH is confirmed by measuring glycine levels in the blood, urine, or cerebrospinal fluid. Genetic testing may also be utilized to identify specific mutations associated with the disorder.
Treatment options for NKH are limited and mainly focus on managing symptoms rather than reversing the condition. Medications such as sodium benzoate or dextromethorphan may be prescribed to help reduce glycine levels. Furthermore, a strict dietary regimen low in protein intake may be recommended.
Given the severity and complexity of the disorder, children with Type I Nonketotic Hyperglycinemia often face significant developmental challenges and require ongoing medical and supportive care.
