Table 3

Number of participants receiving additional investigations

InvestigationNo of participants (% of total)Comments
Blood investigations
 Clotting5Abnormal in one patient, but already known to be abnormal prior to referral for investigation of EDI
 Folate8Not diagnostic in any participant
 C reactive protein1Not diagnostic in any participant
 Erythrocyte sedimentation rate4Not diagnostic in any participant
 Glucose58No abnormalities
 Lactate178Persistently abnormal in one boy investigated at 1.4 years of age with dysmorphia, pulmonary stenosis, squint and hypertonia; MRS showed lactate peak although respiratory chain enzymes normal and no genetic diagnosis of mitochondrial disease made
 Acylcarnitine screen100Not diagnostic in any participant
 Magnesium3Not diagnostic in any participant
 Ammonia67Not diagnostic in any participant
 Homocysteine11Not diagnostic in any participant
 Uric acid103Not diagnostic in any participant
 Lipid/cholesterols40Not diagnostic in any participant
 White cell enzymes45Not diagnostic in any participant
 Very long chain fatty acids60Not diagnostic in any participant
 Transferrin isoelectric focusing46Not diagnostic in any participant
 Galactosaemia screen15Not diagnostic in any participant
 Copper21Not diagnostic in any participant
 Caeruloplasmin20Not diagnostic in any participant
 Free T39Not diagnostic in any participant
 Cortisol12Not diagnostic in any participant
 Vitamin A7Not diagnostic in any participant
 Vitamin B12 10Not diagnostic in any participant
 Vitamin D193Low levels were not felt to be the aetiological cause of EDI in any participant
 Vitamin E9Not diagnostic in any participant
 Coeliac screen40Not diagnostic in any participant
 Amylase5Not diagnostic in any participant
 Parathyroid hormone48Not diagnostic in any participant
 Immunoglobulins42Not diagnostic in any participant
 LDH3Not diagnostic in any participant
 Alpha fetoprotein5Not diagnostic in any participant
 ANA4Not diagnostic in any participant
 Rheumatoid factor2Not diagnostic in any participant
 Congenital infection screen34Not diagnostic in any participant
Urine investigations
 Urine amino acids150Not diagnostic in any participant
 Urine creatinine13Not diagnostic in any participant
 Oligosaccharides12Not diagnostic in any participant
 Purine/pyrimidine studies30Often done after a marginally low uric acid, normal in all participants
Cerebrospinal fluid tests
 CSF glucose lactate58Lactate raised in one boy investigated at 1.4 years of age with dysmorphia, pulmonary stenosis, squint and hypertonia; MRS showed lactate peak although respiratory chain enzymes normal and no genetic diagnosis of mitochondrial disease made
Glucose low in two patients: a boy investigated at 1.7 years with EDI, hypotonia, seizures and paroxysmal upgaze when fasted; a girl investigated at 1.9 years with EDI, left hemiplegia and seizures. Both confirmed to have mutations in Glut 1 deficiency syndrome gene
 CSF amino acids19Diagnostic in two cases: a boy, investigated at 4 months of age for developmental impairment, poor visual function, evolving dystonia and microcephaly diagnosed with serine deficiency; a boy investigated at 0.8 year for developmental impairment, poor visual function and microcephaly whose plasma amino acids revealed low serine, ultimately diagnosed with serine deficiency
 CSF neurotransmitters32N`ot diagnostic in any participant
 CSF viral studies18Not diagnostic in any participant
Other
 Skeletal survey2Not diagnostic in any participant
 Muscle biopsy9Not diagnostic in any participant
 Fibroblast culture2Sent for variety of tests—not diagnostic in any participant
  • ANA, antinuclear antibody; CSF, cerebrospinal fluid; EDI, early developmental impairment; LDH, lactate dehydrogenase; MRS, magnetic resonance proton spectroscopy.