Table 2. NKH symptoms and disease categories.
| Disease Category* | Symptom | Percent Recorded |
|---|---|---|
| Cognitive Disorders | Profound mental retardation (PMR) | 81% |
| Cognitive impairment | ||
| Speech delay | ||
| ADHD | ||
| Aggressive behavior | ||
| Hyperactivity | ||
| Hypoactivity | ||
| Sexual impulsivity | ||
| Stranger anxiety | ||
| Autism | ||
| Delirium | ||
| Seizure | Intractable seizures | 72% |
| Irregular EEG | ||
| Hiccups | ||
| Automatisms | ||
| Eye deviation | ||
| Epilepsy | ||
| Myoclonic seizures | ||
| Multifocal clonus | ||
| Muscle/Movement Control | Brisk reflexes and clonus | 35% |
| Flexor spasms | ||
| Spasticity | ||
| Reduced deep tendon reflexes | ||
| Inability to walk | ||
| Ataxia | ||
| Choreoathetosis | ||
| Dysdiadochokinesia | ||
| Psychomotor delay | ||
| Severe spastic diplegia | ||
| Global developmental delay | ||
| Hemiparesis | ||
| Hypotonia | ||
| Poor suck/failure to feed | ||
| Dysphagia | ||
| Weak cry | ||
| Lethargy | ||
| Brain Malformations / Injury | Coma | 32% |
| Hypoplasia of corpus callosum | ||
| Thin corpus callosum | ||
| Agenesis of corpus callosum | ||
| Microcephaly | ||
| Simplified gyral pattern | ||
| Restricted diffusion | ||
| Myelination pattern changes | ||
| Hydrocephaly | ||
| Respiration | Apnea | 17% |
| Cyanosis | ||
| Respiratory distress | ||
| Respiratory failure | ||
| Respiratory acidosis | ||
| Hormonal Disorders | Hypothyroidism | 2% |
| Premature adrenarche | ||
| Hearing | Hypoacusis | 1% |
| Eyesight | Optic atrophy | 1% |
| Nystagmus | ||
| Immune System | Pyrexia | 1% |
| Digestion | Hypertrophic pyloric stenosis | 1% |
*While elevation of glycine is a diagnostic criterion for NKH, blood glycine level is not a good predictor of subsequent disease progression.