John P. Osborne

Two loci for Tuberous Sclerosis: one on 9q34 and one on 16p13

32 families informative for the segregation of Tuberous sclerosis (TSC) have been examined for genetic markers on chromosomes 9, 11, 12 and 16. In one large family there was clear evidence of linkage to markers on chromosome 16p13.3 (lodscore with D16S291 of 4·7 at θ= 0) but other families were too small to give individually convincing lodscores. Combined results for all families gave positive results with ABO/DBH on chromosome 9 (max lod 2·63) and with D16S291 on chromosome 16 (max lod 3·98) at values of theta of 0·2 in each case. Further analysis showed strong evidence for heterogeneity with approximately half the families linked to a locus TSC1 on chromosome 9 between ASS and D9S298 and half to TSC2 on chromosome 16 close to D16S291. There was no definite support for a third locus although in many families this could not be excluded. In three families the segregation pattern of TSC remains unexplained. In two of these the family apparently segregates for TSC1 but in each case a single affected individual appeared to exclude the whole of the candidate region. Preliminary analysis of clinical features did not reveal any definite differences in incidence of mental handicap between individuals in different linkage groups or with different sex of the parent of origin. The frequencies of periungual fibromas and facial angiofibromas were also similar in both linkage groups. The difficulties of detecting linkage in small families where there is locus heterogeneity are discussed. The program ZZ was found to be helpful in this respect.

The United Kingdom Infantile Spasms Study (UKISS) comparing hormone treatment with vigabatrin on developmental and epilepsy outcomes to age 14 months: a multicentre randomised trial

BACKGROUND Infantile spasms is a severe infantile seizure disorder that is difficult to treat and has a high morbidity. Absence of spasms on days 13 and 14 after randomisation is more common in infants allocated hormone treatments than in those allocated vigabatrin. We sought to assess whether early control of spasms is associated with improved developmental or epilepsy outcomes. METHODS Infants enrolled in the United Kingdom Infantile Spasms Study (UKISS) were randomly assigned hormone treatment (n=55) or vigabatrin (n=52) and were followed up until clinical assessment at 12-14 months of age. We assessed neurodevelopment with the Vineland adaptive behaviour scales (VABS) at 14 months of age on an intention to treat basis. FINDINGS Of 107 infants enrolled, five died and 101 survivors reached both follow-up assessments. Absence of spasms at final clinical assessment (hormone 41/55 [75%] vs vigabatrin 39/51 [76%]) was similar in each treatment group (difference 1.9%, 95% CI -18.3% to 14.4%; chi(2)=0.05; p=0.82). Mean VABS score did not differ significantly (hormone 78.6 [SD 16.8] vs vigabatrin 77.5 [SD 12.7]; difference 1.0, 95% CI -4.9 to 7.0; t(99)=0.35, p=0.73). In infants with no identified underlying aetiology, the mean VABS score was higher in those allocated hormone treatment than in those allocated vigabatrin (88.2 [17.3] vs 78.9 [14.3]; difference 9.3, 95% CI 1.2 to 17.3; t(95)=2.28, p=0.025). INTERPRETATION Hormone treatment controls spasms better than does vigabatrin initially, but not at 12-14 months of age. Better initial control of spasms by hormone treatment in those with no identified underlying aetiology may lead to improved developmental outcome.

The United Kingdom Infantile Spasms Study comparing vigabatrin with prednisolone or tetracosactide at 14 days: a multicentre, randomised controlled trial

BACKGROUND Infantile spasms, which comprise a severe infantile seizure disorder, have a high morbidity and are difficult to treat. Hormonal treatments (adrenocorticotropic hormone and prednisolone) have been the main therapy for decades, although little evidence supports their use. Vigabatrin has been recorded to have a beneficial effect in this disorder. We aimed to compare the effects of vigabatrin with those of prednisolone and tetracosactide in the treatment of infantile spasms. METHODS The United Kingdom Infantile Spasms Study assessed these treatments in a multicentre, randomised controlled trial in 150 hospitals in the UK. The primary outcome was cessation of spasms on days 13 and 14. Minimum doses were vigabatrin 100 mg/kg per day, oral prednisolone 40 mg per day, or intramuscular tetracosactide depot 0.5 mg (40 IU) on alternate days. Analysis was by intention to treat. FINDINGS Of 208 infants screened and assessed, 107 were randomly assigned to vigabatrin (n=52) or hormonal treatments (prednisolone n=30, tetracosactide n=25). None was lost to follow-up. Proportions with no spasms on days 13 and 14 were: 40 (73%) of 55 infants assigned hormonal treatments (prednisolone 21/30 [70%], tetracosactide 19/25 [76%]) and 28 (54%) of 52 infants assigned vigabatrin (difference 19%, 95% CI 1%-36%, p=0.043). Two infants allocated tetracosactide and one allocated vigabatrin received prednisolone. Adverse events were reported in 30 (55%) of 55 infants on hormonal treatments and 28 (54%) of 52 infants on vigabatrin. No deaths were recorded. INTERPRETATION Cessation of spasms was more likely in infants given hormonal treatments than those given vigabatrin. Adverse events were common with both treatments.

A Proposal for Case Definitions and Outcome Measures in Studies of Infantile Spasms and West Syndrome: Consensus Statement of the West Delphi Group

Summary:  Purpose: To reach a broad consensus on case definitions, outcomes, and outcome measures that will ease future study design and facilitate comparison of data from different studies of infantile spasms and West syndrome.

MORBIDITY ASSOCIATED WITH TUBEROUS SCLEROSIS: A POPULATION STUDY

Neurological complications and other causes of morbidity were studied in 122 of 131 individuals (64 males. 67 females) with tuberous sclerosis, in a population in which its prevalence was 1/26,500. Seizures occurred in 78 per cent, beginning at less than one year of age in 69 per cent (in more males than females in both cases) and after age 16 in 4 per cent. More males than females also had infantile spasms and persistent seizures. Learning disorder occurred in 53 per cent (also in more males), all with a history of seizures, and was strongly correlated with age at onset of seizures, type of seizure and outcome for seizure control. Of subjects with learning disorder. 85 per cent required supervision for daily living and 65 per cent had little or no language: 97 per cent were fully mobile. Hcmiparesis had occurred in eight of the 131, giant cell astrocytomas in nine, bilateral polycystic kidney disease in two. and haemorrhagic complication relating to renal angiomyolipomas in six.

The cutaneous features of tuberous sclerosis : a population study

Summary We report the cross‐sectional age‐related prevalence of cutaneous features of the tuberous sclerosis complex in a defined population. Of 131 affected individuals, 126 (96%) exhibited skin signs. Although there is considerable variation in the age of expression of all the skin lesions, there is a trend towards the earlier expression of hypomelanic macules and forehead fibrous plaques compared with facial angiofibromas and ungual fibromas. Shagreen patches are usually present by puberty. Ungual fibromas appeared for the first time as late as the fifth decade and were the only clinical feature in three individuals. Gum fibromas were present in 36%. Ten individuals (8%) presented because of the skin manifestations and 21% received treatment for symptomatic skin lesions. Two individuals had large hamartomas at unusual sites (occiput and forearm).

The relation of infantile spasms, tubers, and intelligence in tuberous sclerosis complex

Background: The aetiology of the learning difficulty in tuberous sclerosis is debated. It may be related to the amount of tubers in the brain or caused by the infantile spasms that occur in early life. Aims: To examine the relative contributions to final intelligence (IQ) made by both cerebral tubers and infantile spasms. Methods: As part of an epidemiological study of tuberous sclerosis in the south of England, patients were recruited who were able to undergo magnetic resonance imaging (MRI) without the need for an anaesthetic. Epilepsy history was determined by interview and review of clinical records. IQ was assessed using either Wechsler intelligence scales or Raven’s matrices. Results: A total of 41 patients consented to have an MRI scan. IQ scores were normally distributed about a mean of 91. Twenty six patients had a positive history of epilepsy, and 11 had suffered from infantile spasms. There was a significant relation between the number of tubers and IQ. Infantile spasm status partly confounded the relation between tubers and IQ, but did not render the relation statistically insignificant. The relation between infantile spasms and learning difficulty remained strong even when controlling for the number of tubers.

Prevalence of tuberous sclerosis estimated by capture-recapture analysis.

time. Unfortunately, in human populations these assumptions are frequently violated. The problem can be minimised by the use of techniques such as log-linear modelling but a high degree of accuracy in the estimate of numbers of missing cases should not be expected. We carried out a capture-recapture analysis of data collected in the survey of prevalence of tuberous sclerosis in Wessex. Cases had been identified from a large number of different sources. Data from these individual sources were pooled to construct three summary sources: cases identified by paediatricians; cases identified by other medical practitioners; and cases identified from other sources (for example, the Tuberous Sclerosis Association or Hospital Activity Analysis). We used the method described by Hook and Regal to first derive estimates for the total number of cases from each of the three possible two-source models and finally from all three sources. The figure shows the number of cases identified from each source and the overlap between sources. No cases were identified from all three sources. Maximum likelihood estimates are given for the total number of people with tuberous sclerosis in this population derived from each of the two-source models and from the three-source model. Dependency between sources was investigated by including terms for interaction between sources in the loglinear model; none of these terms was statistically significant. The Wessex survey originally identified 131 cases of tuberous sclerosis in a population of 3·4 million. The results of the capture-recapture analysis suggest that, despite the efforts of the investigators to locate all cases, more than half remained undetected. A revised estimate of prevalence, taking account of unascertained cases, is 8·8 per 100 000 population (95% CI 6·8–12·4). One implication is that many people with tuberous sclerosis do not receive either genetic counselling or specialist medical supervision.

An epidemiological study of renal pathology in tuberous sclerosis complex

To report the frequency of renal symptoms and complications of patients with tuberous sclerosis complex (TSC), to describe the ultrasonographic appearance of the kidneys in a population‐based sample, and to investigate the relationship between a history of renal haemorrhage and renal lesions identified by ultrasonography.

Vigabatrin in the treatment of infantile spasms in tuberous sclerosis: literature review.

The purpose of this report is to review the efficacy and safety of vigabatrin in the treatment of infantile spasms in infants suffering from tuberous sclerosis complex. We reviewed all studies published in the English-language literature investigating the use of vigabatrin in the treatment of infantile spasms. Ten studies gave results for the efficacy of vigabatrin in infantile spasms for infants both with and without underlying diagnoses of tuberous sclerosis. Of the 313 patients without tuberous sclerosis complex, 170 (54%) had complete cessation of their infantile spasms; of the 77 patients with tuberous sclerosis complex, 73 (95%) had complete cessation of their seizures. We conclude that vigabatrin should be considered as first-line monotherapy for the treatment of infantile spasms in infants with either a confirmed diagnosis of tuberous sclerosis or those at high risk, ie, those with a first-degree relative with tuberous sclerosis complex. Paradoxically, in those without tuberous sclerosis complex, vigabatrin might be less efficacious than suggested by studies including patients with tuberous sclerosis complex. (J Child Neurol 1999;14:71-74).