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with autosomal dominant inheritance and at least two genes have been identified  one on
chromosome 20q (KCNQ2) and one on 8q (KCNQ3). Some consider this syndrome to be the
earliest form of idiopathic generalised epilepsy. Neurological and developmental outcome is
normal, but approximately 10–12% of these infants develop later epilepsy (in adolescence or
in early adult life), usually generalised tonic-clonic seizures. In most infants, seizures resolve
between six weeks and six months of age. The precise incidence (and prevalence) of this
syndrome is unknown. The inter-ictal EEG is usually normal.

Benign non-familial (sporadic) neonatal convulsions (seizures)9

This is another rare type of neonatal convulsions, again with no obvious cause. It is likely
that this represents the entity known previously as ‘fifth day fits’, which was once considered
(entirely erroneously), to be due to zinc deficiency. Seizures may persist for longer than in
the familial form but late epilepsy is much less common (under 1%), and may have no causal
relationship.

Epilepsy of infancy with migrating focal seizures (migrating partial seizures in
infancy10,11)

Although this would appear to be a rare syndrome it is probably under-recognised, like most
new epilepsy ‘syndromes’. Most infants present at less than six months of age and the
majority at less than six weeks of age. The seizures are brief but multiple and at their peak
may occur over 50 or 60 times per day. Eye and/or head deviation, autonomic features (facial
flushing and epiphora) and some facial/limb clonic activity characterize the seizures. As the
name implies, the seizures originate from (and migrate to) different parts of the brain – both
clinically and electrically, in the EEG. Developmental progress is generally very poor (from
the onset of the seizures) and survivors usually have moderate or severe learning difficulties.
Many infants die under two or three years of age. There is emerging evidence of a genetic
aetiology to this disorder with mutations in KCNT1 being the most frequently reported but
also cases with SLC25A22, SCN1A, SCN2A, TBC1D24, SCN8A and CHD2 mutations.
Seizure-control is usually very poor and no one anticonvulsant has proved to be any more
effective than another. Ketogenic diet and vagal nerve stimulation also are generally
ineffective. There has been some recent interest in gene-targeted treatment in children with
KCNT1 mutations using quinidine, however further evaluation of this is required12.

Myoclonic epilepsy in infants

Early onset, severe (early myoclonic encephalopathy) (EME). The condition may be
independent from, or, far less likely, may overlap with Ohtahara syndrome13 (early infantile
epileptic encephalopathy with burst-suppression on EEG). Both syndromes are severe
epileptic encephalopathies with a poor prognosis; seizures are typically resistant to treatment,
psychomotor retardation is both inevitable and profound and life expectancy is limited. In
EME seizures typically start in the first two months of life (with the majority starting in the
first ten days) and myoclonic seizures are frequent (distinguishing the condition from
Ohtahara syndrome). Metabolic aetiologies are common (non-ketotic hyperglycinaemia is
the commonest metabolic aetiology, and amino and organic acidopathies, urea cycle
disorders, mitochondrial disorders, pyridoxine and pyridoxal-5-phosphate disorders,
molybdenum cofactor deficiency, sulfite oxidase deficiency, Menke syndrome, Zellweger
syndrome and other disorders are also seen) and structural abnormalities are rare. A number
of familial cases have been reported raising the possibility of a genetic aetiology. Gene
mutations have been found in ErbB4.

Treatable metabolic aetiologies should be investigated at presentation and all infants should