Clinical and laboratory outcomes of ketogenic versus glycine-restricted diet in nonketotic hyperglycinemia: A comparative study

BOZACI A. E., Erdal İ., ÖNER G., Clark Ö. A., Köken Ö. Y., Soyuçen E.

Molecular Genetics and Metabolism, cilt.148, sa.2, 2026 (SCI-Expanded, Scopus) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 148 Sayı: 2
  • Basım Tarihi: 2026
  • Doi Numarası: 10.1016/j.ymgme.2026.110118
  • Dergi Adı: Molecular Genetics and Metabolism
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, Chemical Abstracts Core, EMBASE, MEDLINE
  • Anahtar Kelimeler: glycine encephalopathy, Inborn errors of metabolism, Ketogenic therapy, Metabolic epilepsy, Seizure control
  • Akdeniz Üniversitesi Adresli: Evet

Özet

Aim: This study aimed to compare the clinical, biochemical, and nutritional outcomes of classical nonketotic hyperglycinemia (NKH) patients treated with a ketogenic diet (KD) versus a glycine-restricted diet (GRD). Methods: This retrospective study included patients with classical nonketotic hyperglycinemia treated with either a KD (n = 8) or a GRD (n = 6). Seizure frequency, seizure scores, antiepileptic drug (AED) use, motor function (GMFCS-E&R), swallowing difficulties, plasma glycine levels, and nutritional parameters were evaluated before and after dietary treatment. Results: Baseline characteristics did not differ significantly between groups. Post-treatment assessments showed no significant differences in GMFCS scores, swallowing function, or plasma glycine levels. However, KD resulted in significantly reduced seizure frequency and seizure scores, and decreased AED use compared with GRD. Within-group analysis showed significant seizure control in the KD group, whereas seizure frequency increased in the GRD group. An increase in LDL cholesterol was observed in KD group, as expected; other nutritional parameters remained stable. Mortality was similarly high in both groups. Conclusion: Neither diet altered biochemical parameters or motor outcomes. However, KD provided better seizure control compared to GRD, supporting its role as a useful adjunctive therapy in NKH.