Table 1.
Clinical details of family members with reported neonatal seizures
| Patients | IV.2 (IP) | IV.4 | IV.5 | III.4 | II. 1 | III.6 |
|---|---|---|---|---|---|---|
| Current age, years | 4 | 2 | 1 | 31 | 55 | 19 |
| Mutation | KCNQ3 c.835G>T (het) P.V279F KCNQ2 c.297–18C>T p.? | KCNQ3 c.835G>T (het) p.V279F | KCNQ3 c.835G>T (het) P.V279F KCNQ2 wild type | KCNQ3 c.835G>T (het) P.V279F | not done | not done |
| Sex | M | F | M | F | F | M |
| Exam at birth (length, weight, OFC) | 48 cm, 3, 130 g, 34.5 cm, Apgar 10/10/10, pH 7.28 | 2,725 g, 47 cm, 39 cm | 3, 160 g, 47 cm, 35 cm, Apgar 9/10/10 | 3,000 g, 49 cm, 33 cm, Apgar 9/10/10 | not known | not known |
| Gestational age, weeks | 39+2 | 39+2 | 39+0 | 39+3 | not known | not known |
| Seizure onset (day of life) | d5 | d6 | d5 | d3 | during first week | during first week |
| Seizure type at onset | focal clonic, secondary GTCS with cyanosis, multiple per day | focal clonic, secondary GTCS with cyanosis, multiple per day | focal clonic, secondary GTCS with cyanosis, multiple per day | tonic and focal clonic, GTCS with cyanosis, multiple per day | cyanotic spells | cyanotic spells |
| Seizure cessation (day of life) | d20 | d12 | d10 | d4 | not available | not available |
| Treatment and outcome | unsuccessful trials with pyridoxine, pyridoxal-phosphate, folinic acid, LEV after d9, slowly increasing up to 65 mg/kg on d20 (no further seizures after d20) | LEV after d12, up to 70 mg/kg (no further seizures after first dose) | LEV after d6, up to 85 mg/kg on d8 (still up to 4 seizures per day), OXC after d10, up to 20 mg/kg (no further seizures after first dose) | no treatment | no treatment, spells prompted cardiological monitoring and investigations | not available |
| Associated movement disorder | not reported | not reported | not reported | not reported | not reported | not reported |
| Seizure outcome | seizure free | single febrile seizure at 5 months | seizure free | putative seizure at 12 years | seizure free | seizure free |
| EEG at onset | focal sharp wave on ictal and interictal EEG, normal background activity | focal sharp wave on ictal EEG, normal interictal EEG, normal background activity | normal interictal EEG, normal background activity | normal interictal EEG, normal background activity | not known | not known |
| EEG at follow-up | normal | at 6 weeks, focal sharp waves on interictal EEG, normal EEG after 5 months | normal | normal | not known | not known |
| Developmental outcome | normal at 4 years | normal at 2 years | normal | normal | normal | normal |
| Brain imaging | normal MRI at d6 | normal ultrasound at d6 | normal ultrasound at d6 | not done | not done | not done |
| Additional investigations | normal results for tandem-MS, urinary organic acids, creatine metabolism; CSF analysis incl. glucose quotient, neurotransmitter, pterines, sulfite test | no additional investigations | no additional investigations | CSF analysis | not known | not known |
CSF = Cerebrospinal fluid; GTCS = generalized tonic-clonic seizures; OFC = occipitofrontal circumference; tandem-MS = tandem mass spectrometry.