Tuberous sclerosis: the incidence of sporadic cases versus familial cases

Tumorigenesis Mechanisms Found in Hereditary Renal Cell Carcinoma: A Review

Renal cell carcinoma is a heterogenous cancer composed of an increasing number of unique subtypes each with their own cellular and tumor behavior. The study of hereditary renal cell carcinoma, which composes just 5% of all types of tumor cases, has allowed for the elucidation of subtype-specific tumorigenesis mechanisms that can also be applied to their sporadic counterparts. This review will focus on the major forms of hereditary renal cell carcinoma and the genetic alterations contributing to their tumorigenesis, including von Hippel Lindau syndrome, Hereditary Papillary Renal Cell Carcinoma, Succinate Dehydrogenase-Deficient Renal Cell Carcinoma, Hereditary Leiomyomatosis and Renal Cell Carcinoma, BRCA Associated Protein 1 Tumor Predisposition Syndrome, Tuberous Sclerosis, Birt-Hogg-Dubé Syndrome and Translocation RCC. The mechanisms for tumorigenesis described in this review are beginning to be exploited via the utilization of novel targets to treat renal cell carcinoma in a subtype-specific fashion.

Tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is a neurocutaneous syndrome that can affect the brain, skin, eyes, kidneys, heart, and lungs. TSC alters cellular proliferation and differentiation, resulting in hamartomas of various organs, tumor formation, and altered neuronal migration. The phenotype is highly variable. Most individuals have seizures, commonly including infantile spasms, and there is variable intellectual disability and autism. Neonates can present with cardiac failure due to intracardiac rhabdomyomas. The likelihood of renal angiomyolipomas increases with age, and renal disease is the most common cause of death in adults with TSC. Pulmonary involvement occurs predominantly in women and carries a high morbidity and mortality. TSC is inherited as an autosomal dominant trait, but spontaneous mutations are common. A mutation of either TSC1 on chromosome 9 or TSC2 on chromosome 16 leads to dysfunction of hamartin or tuberin, respectively. These two proteins form a functional complex that modulates the mammalian target of rapamycin (mTOR) pathway. Medications that inhibit mTOR are being used to treat TSC-related tumors, and current studies are investigating whether these agents could alleviate other TSC complications. Consensus statements guide identification and optimal management of many of the TSC-related complications at diagnosis and throughout the lifespan. A multidisciplinary approach is necessary for optimal management of individuals with TSC.

Tuberous sclerosis-associated renal cell carcinoma: a clinicopathologic study of 57 separate carcinomas in 18 patients

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder with characteristic tumors involving multiple organ systems. Whereas renal angiomyolipoma (AML) is common in TSC, renal cell carcinoma (RCC) is rarely reported. Fifty-seven RCCs from 13 female and 5 male TSC patients were reviewed. Age at surgery ranged from 7 to 65 years (mean: 42 y). Nine patients (50%) had multiple synchronous and/or metachronous RCCs (range of 2 to 20 RCCs) and 5 had bilateral RCCs (28%). Seventeen patients (94%) had histologically confirmed concurrent renal AMLs, including 15 with multiple AMLs (88%) and 9 (50%) with AMLs with epithelial cysts. None of the 15 patients with available clinical follow-up information had evidence of distant metastatic disease from 6 to 198 months after their initial surgery (mean: 52 mo). The 57 RCCs exhibited 3 major distinct morphologies: (1) 17 RCCs (30%) had features similar to tumors previously described as "renal angiomyoadenomatous tumor" or "RCC with smooth muscle stroma"; (2) 34 RCCs (59%) showed features similar to chromophobe RCC; and (3) 6 RCCs (11%) showed a granular eosinophilic-macrocystic morphology. Distinct histologic changes were also commonly present in the background kidney parenchyma and included cysts or renal tubules lined by epithelial cells with prominent eosinophilic cytoplasm, nucleomegaly, and nucleoli. Immunohistochemically, all RCCs tested showed strong nuclear reactivity for PAX8 and HMB45 negativity. Compared with sporadic RCCs, TSC-associated RCCs have unique clinicopathologic features including female predominance, younger age at diagnosis, multiplicity, association with AMLs, 3 recurring histologic patterns, and an indolent clinical course. Awareness of the morphologic and clinicopathologic spectrum of RCC in this setting will allow surgical pathologists to better recognize clinically unsuspected TSC patients.

[Neuro-encephalic features of tuberous sclerosis complex]

Tuberous sclerosis is a phacomatosis resulting from an autosomal dominant inheritance. It is characterized by the presence of multiple hamartomas in various organs, especially the brain, the skin, the kidneys and the heart. The diagnosis of tuberous sclerosis is based on imaging and clinical examination, where magnetic resonance imaging constitutes the key investigation showing characteristic brain lesions. Neuro-encephalic manifestations may be particularly severe, and may even be life threatening. The authors report personal cases series and review the literature highlighting epidemiology, clinical features and imaging of neuro-encephalic tuberous sclerosis.

Epilepsy in the setting of neurocutaneous syndromes

The neurocutaneous syndromes are characterized by congenital dysplastic abnormalities involving the skin and nervous system. The commonest neurocutaneous syndromes manifesting epilepsy are tuberous sclerosis and the Sturge-Weber syndrome. Neurofibromatosis and other lesser-known entities, such as epidermal nevus syndrome, are also known to be accompanied by epilepsy. These syndromes are not related to one another. This article reviews what has been learned about the epileptic syndromes in these disorders.

The clinical utility of the Social Responsiveness Scale and Social Communication Questionnaire in tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is often associated with epilepsy, mental retardation, and autism spectrum disorders (ASDs). Thus, screening for ASDs is important when evaluating these individuals. We examined the utility of the Social Responsiveness Scale (SRS) and Social Communication Questionnaire (SCQ), two measures for screening for ASDs, in a TSC population. Twenty-one children were evaluated, with 52.4% classified as having ASDs on the SRS and 42.9% classified as such on the SCQ. Number of antiepileptic drugs significantly correlated with SRS Total score, as did level of intellectual functioning. Evidence for convergent validity was obtained between the SRS and SCQ Total scores (r=0.605). Moreover, all SRS subscales correlated with SCQ Total score (r>0.400). All SCQ subscales except for Communication correlated with SRS total. Overall, the results demonstrate that these questionnaires appear to be effective screens for ASDs in a TSC population and are measuring similar constructs.

[Phacomatosis and genetically determined tumors: the transition from childhood to adulthood]

Phacomatoses, or neurocutaneous disorders, are a group of congenital and hereditary diseases characterized by developmental lesions of the neuroectoderm, leading to pathologies affecting the skin and the central nervous system. There is a wide range of pathologies affecting individuals at different moments of life. The genetics is variable: while neurofibromatosis 1 and 2, tuberous sclerosis and von Hippel-Lindau disease are all inherited as autosomal dominant traits, Sturge-Weber syndrome is sporadic. Other neurocutaneous disorders can be inherited as autosomal recessive traits (i.e., ataxia-telangiectasia), X-linked (i.e., incontinentia pigmenti) or explained by mosaicism (i.e., hypomelanosis of Ito, McCune-Albright syndrome). In this review, we discuss the major types of neurocutaneous disorders most frequently encountered by the neurosurgeon and followed beyond childhood. They include neurofibromatosis types 1 and 2, tuberous sclerosis, Sturge-Weber syndrome and von Hippel-Lindau disease. In each case, a review of the literature, including diagnosis, genetics and treatment will be presented. The lifespan of the disease with the implications for neurosurgeons will be emphasized. A review of cases, including both pediatric and adult patients, seen in neurosurgical practices in the Lille, France and Lausanne, Switzerland hospitals between 1961 and 2007 is presented to illustrate the pathologies seen in different age-groups. Because the genes mutated in most phacomatoses are involved in development and are activated following a timed schedule, the phenotype of these diseases evolves with age. The implication of the neurosurgeon varies depending on the patient's age and pathology. While neurosurgeons tend to see pediatric patients affected with neurofibromatosis type 1, tuberous sclerosis and Sturge-Weber syndrome, there will be a majority of adult patients with von Hippel-Lindau disease or neurofibromatosis type 2.

Intrafamilial phenotypic variability in tuberous sclerosis complex

Clinical manifestations were retrospectively assessed in 5 families with tuberous sclerosis complex, including 1 pair of monozygotic twins. Interfamilial variation in tuber count was significantly larger than intrafamilial variation. Severity of epilepsy and cognitive profiles varied both between and within families, particularly between the monozygotic twins, and IQ was inversely related to tuber count. Cutaneous, renal, and cardiac findings did not appear to cluster within families. Although the monozygotic twins displayed similar physical manifestations of tuberous sclerosis complex (renal and cardiac hamartomas), they differed markedly in neurocognitive profiles. Phenotypic variation within these families may be explained largely as a function of the randomness of second-hit events that cause hamartomas in tuberous sclerosis complex or by as-yet-unidentified genetic modifiers. Familial variation in tuberous sclerosis complex phenotype has important implications for genetic counseling.

Tuberous sclerosis: a syndrome of incomplete tumor suppression

Tuberous sclerosis (TS) is a congenital neurocutaneous syndrome (or phacomatosis) characterized by widespread development of hamartomas in multiple organs. For affected individuals, neurological and psychiatric complications are the most disabling and lethal features. Although the clinical phenotype of TS is complex, only three lesions characterize the neuropathological features of the disease: cortical tubers, subependymal nodules, and subependymal giant cell astrocytomas. The latter is a benign brain tumor of mixed neuronal and glial origin. Tuberous sclerosis is caused by loss-of-function mutations in one of two genes, TSC1 or TSC2. The normal cellular proteins encoded by these genes, hamartin and tuberin, respectively, form a heterodimer that suppresses cell growth in the central nervous system by dampening the phosphatidylinositol 3–kinase signal transduction pathway. The authors review the clinical and neuropathological features of TS as well as recent research into the molecular biology of this disease. Through this work, investigators are beginning to resolve the paradoxical findings that malignant cancers seldom arise in patients with TS, even though the signaling molecules involved are key mediators of cancer cell growth.

Anaesthetic management of children with tuberous sclerosis

BACKGROUND

Tuberous sclerosis (TS) is a hamartomatous disease that usually presents with cutaneous and intracranial lesions, but can also affect other organ systems.

METHODS

In this report, we retrospectively reviewed the perioperative course of 24 children with TS who had medically intractable seizures as the primary disease process.

RESULTS

Cardiac rhabdomyoma was detected in 11 of 18 patients who had a cardiac evaluation, and coexisting congenital heart defects were diagnosed in six. Ten of 17 patients who had a renal evaluation were diagnosed with renal TS, presenting with azotaemia in one and hypertension in four. The major perioperative complications in the 52 anaesthetics, included death (a neonate after cardiac rhabdomyoma resection), seizures (five patients) and bradyarrhythmias (two patients).

CONCLUSIONS

Patients with TS and neurological disorders frequently have coexisting cardiac and renal disease as well. Patients with TS should be evaluated for these organ specific disorders prior to surgery.

Dermatologic clues to inherited disease

Genetic diseases often have cutaneous manifestations, which can be the first or most prominent signs of the underlying problem. Recognition of these dermatologic clues allows prompt diagnosis and intervention. In this article, the authors have attempted to outline several important examples of genodermatoses.

Tuberous Sclerosis Consensus Conference: recommendations for diagnostic evaluation. National Tuberous Sclerosis Association

At the recent Tuberous Sclerosis Consensus Conference, a subcommittee proposed recommendations to guide the rational use of diagnostic studies in patients with tuberous sclerosis complex. Recommendations were made for diagnostic evaluation at the time of diagnosis, when testing helps both to establish the diagnosis and to identify potential complications. Additional guidelines were proposed for the ongoing surveillance of established patients to detect later complications of tuberous sclerosis complex. In the absence of comprehensive population studies to govern the use of diagnostic studies in individuals with tuberous sclerosis complex, the panel developed guidelines based on the disorder's natural history, concentrating on complications that are common, clinically significant, and more easily managed when found early. Finally, the group made suggestions for the use of diagnostic tests to identify family members who have tuberous sclerosis complex. Although these recommendations should standardize and improve our use of diagnostic studies in individuals with tuberous sclerosis complex, the clinical approach in a given patient must remain flexible enough to meet the needs of individual patients and families.

Prenatal diagnosis of tuberous sclerosis with intracerebral signs at 14 weeks' gestation

We report the ultrasound detection of cranial abnormalities at 14 weeks' gestation in a fetus subsequently confirmed as having tuberous sclerosis using DNA linkage analysis within the affected family. The presence of asymmetrical ventricular enlargement persisted antenatally. Magnetic resonance imaging at 26 weeks indicated the possibility of poor gyral formation consistent with a neuronal migration disorder. Cardiac rhabdomyomata were not visualized on ultrasound scan until 30 weeks' gestation. Postnatal cranial ultrasound confirmed the significant neuropathology which was manifested by severe developmental delay and intractable fits in the child. The potential benefits of earlier diagnosis of tuberous sclerosis by cranial imaging are discussed, although in this patient the routine booking scan resulted in a path of prenatal diagnosis being undertaken which had originally been declined. A mechanism is proposed to explain the variable expression of tuberous sclerosis within this family based on altered TSC2 activity affecting neuronal migration.

Comprehensive mutation analysis of TSC1 and TSC2-and phenotypic correlations in 150 families with tuberous sclerosis

Tuberous sclerosis (TSC [MIM 191090 and MIM 191100]) is an autosomal dominant disorder characterized by hamartomas in many organs. Two thirds of cases are sporadic and are thought to represent new mutations. TSC is caused by mutations affecting either of the presumed tumor-suppressor genes, TSC1 and TSC2. Both appear to function as tumor suppressors, because somatic loss or intragenic mutation of the corresponding wild-type allele is seen in the associated hamartomas. Here we report the first comprehensive mutation analysis of TSC1 and TSC2 in a cohort of 150 unrelated TSC patients and their families, using heteroduplex and SSCP analysis of all coding exons and using pulsed-field gel electrophoresis and conventional Southern blot analysis and long PCR to screen for large rearrangements. Mutations were characterized in 120 (80%) of the 150 cases, affecting TSC1 in 22 cases and TSC2 in 98 cases. TSC1 mutations were significantly underrepresented in sporadic cases (P=. 000185). Twenty-two patients had TSC2 missense mutations that were found predominantly in the GAP-related domain (eight cases) and in a small region encoded in exons 16 and 17, between nucleotides 1849 and 1859 (eight cases), consistent with the presence of residues performing key functions at these sites. In contrast, all TSC1 mutations were predicted to be truncating, consistent with a structural or adapter role for the encoded protein. Intellectual disability was significantly more frequent in TSC2 sporadic cases than in TSC1 sporadic cases (P=.0145). These data provide the first representative picture of the distribution and spectrum of mutations across the TSC1 and TSC2 loci in clinically ascertained TSC and support a difference in severity of TSC1- and TSC2-associated disease.

Developmental enamel defects in tuberous sclerosis: a clinical genetic marker?

Ten probands with tuberous sclerosis (TS) and 20 first degree relatives were examined for evidence of pitted enamel hypoplasia; 100% of TS patients had pitting, compared to 65% of relatives and 72% of 25 controls. We found that 70% of TS cases had more than 14 pits per person compared with only 5% of relatives and 4% of controls; 85% of relatives and 84% of controls had fewer than six pits per person. Our results confirm that significantly increased numbers of dental enamel pits are found in persons with TS compared to controls. These results suggest that examination for the presence or absence of dental enamel pits is not a useful screening test for first degree relatives to detect otherwise unsuspected subjects with tuberous sclerosis. However, the lack of pits in first degree relatives in our study is probably largely because none of the relatives appeared to carry the TS gene.

Tuberous sclerosis--an unusual cause of seizures in an 18 year old

An 18 year old man presenting with seizures was found to have hypomelanotic macules and a cardiac rhabdomyoma. These features suggested a diagnosis of tuberous sclerosis (TS) but there were no other clinical signs, no family history and cranial imaging failed to reveal the characteristic appearances. The diagnostic criteria for TS are reviewed and the importance of thorough clinical examination and appropriate investigation in this disease is stressed.

Neurocutaneous syndromes

Many of the neurocutaneous disorders are more common than once suspected, in part because patients with milder forms of the disorders are now more likely to be recognized. Improved diagnostic studies and increasingly specific medical and surgical therapy allow some previously untreatable complications to be successfully managed. Genetic linkage analysis has localized the abnormal gene for some of the hereditary neurocutaneous disorders onto specific chromosomes, and newly developed clinical diagnostic criteria have improved our ability to establish a definite diagnosis in less obvious patients. Thus, the outlook for these patients is no longer uniformly pessimistic.

A fetal cystic neck mass associated with maternal tuberous sclerosis. Case report and literature review

Tuberous sclerosis is a single gene autosomal-dominant disorder, characterized by multiple hamartoma formation. It shows a wide variability of expression. Prenatal diagnosis by means of a DNA or biochemical marker is not yet possible. Ultrasound offers the only way to detect possible antenatal hamartoma formation, which is most commonly found in the central nervous system, the renal system, and the heart. We report a case of fetal involvement that appears unique because of the unusual location of a tumour in the neck of the fetus.

Tuberous sclerosis. Diagnostic problems in a family

This paper describes a family in which the first child, a girl born in 1988, has tuberous sclerosis (TS). The 28-year-old mother had no symptoms of TS but at ocular examination she presented with progressively increasing prominence of the optic nerve heads with a few glistening spots due to deep and superficial drusen, and tilted disks. Visual fields showed enlarged blind spots. Fluorescein angiography showed lobular drusen of the optic nerve heads. The ERG showed an absent B-wave. The family history was negative for TS. The question arises whether these ocular findings have to be interpreted as part of the syndrome of TS. In that case the recurrence risk for the disease is 50% for each next child. Assuming a spontaneous mutation in the first child, however, the risk can be nearly neglected. Until the genetic defect in TS is found, these problems in genetic counselling of parents with a child with TS will remain unsolved. Prenatal diagnosis by DNA-analysis is not yet possible; however a few cases of TS have been diagnosed prenatally by fetal ultrasonography of the heart, as was the case in the affected child.

The value of investigation for genetic counselling in tuberous sclerosis

Forty sets of parents and 24 sibs of patients with tuberous sclerosis were investigated by an extensive protocol, including clinical examination of skin, hair, and oral cavity, direct and indirect ophthalmoscopy, cranial CT scan, renal ultrasound, and a radiological skeletal survey. None of the clinical examinations provided evidence that any of the subjects was affected. Similarly, the cranial CT scan, renal ultrasound, and skeletal survey failed to identify any occult gene carriers. All of these investigations showed abnormalities in some parents but none was diagnostic. This study shows the difficulties in interpretation that these investigations may produce with consequent problems for genetic counselling. The study does not support the routine use of these tests. There are published reports where the diagnosis of tuberous sclerosis has been made in adults exclusively on a CT scan and an argument can be made for including this investigation. There is no indication for performing renal ultrasound nor skeletal x rays in parents who have normal clinical examinations.

Diagnostic and counselling difficulties using a fully comprehensive screening protocol for families at risk for tuberous sclerosis

Tuberous sclerosis (TS) results from an autosomal dominant gene which exhibits variable expression and reduced penetrance. Although there are well established diagnostic criteria for TS, examination of first degree relatives can cause diagnostic criteria for TS, examination of first degree relatives can cause diagnostic problems with consequent difficulties in genetic counselling. Using an extensive, non-invasive protocol consisting of skin examination with Wood's lamp, cranial CT scan, specialist ophthalmological and dental examination, skeletal survey, and echocardiography, we have examined 56 first degree relatives of persons with TS. These consisted of 40 parents and seven sibs from 25 sporadically affected families and nine persons from seven multigeneration families. In seven of the apparently sporadically affected families, three mothers had echocardiographical findings consistent with one or more rhabdomyoma. In another, the mother's renal ultrasound showed evidence of single cysts in both kidneys. In a fifth family, the father had suggestive but not diagnostic features of TS on the cranial CT scan and skeletal survey. In the sixth family, the mother was found to have atypical calcification on CT scan. In a seventh instance a sib from a two generation family had echocardiographical evidence of a rhabdomyoma. Even though the proband in three of the sporadically affected families presented with fits, developmental delay, and depigmented patches, and therefore did not strictly fulfil the diagnostic criteria for TS, two mothers were found to have evidence of rhabdomyomata on echocardiography and the brother of the third had typical depigmented patches. Although the presently accepted diagnostic criteria for TS may not allow one to make a definitive diagnosis of TS in these relatives, we recommend that an extensive screening protocol be used to examine first degree relatives and that caution be used in counselling apparently unaffected members of families at risk for TS.

Developmental enamel defects in primary teeth in children with cerebral palsy, mental retardation, or hearing defects: a review

Developmental enamel defects in primary teeth have been found at least twice as frequently in children with cerebral palsy or mental retardation as in control children, and frequently also in children with sensori-neural hearing deficits. The developing tooth germ is sensitive to a range of systemic disturbances, some of which may also affect neurologic development. Because the enamel cannot recover once it is damaged, it may provide a repository of information on the timing and nature of insults potentially affecting other ectodermally derived structures, including the brain. This paper reviews the literature on developmental defects of enamel in primary teeth, asking whether these might be useful as biological markers of the timing and in some cases the nature of insults. Among systemic factors related to development of enamel that might also have implications for neurologic development are certain genetic disorders including tuberous sclerosis, premature birth, neonatal nutritional disturbances (especially hypocalcemia), viral infections (such as rubella and cytomegalovirus during gestation), thyroid disorders, and maternal diabetes. It is concluded that further research is warranted concerning whether developmental defects of dental enamel can be useful markers for the timing of intra-uterine or perinatal events associated with certain neurologic and sensory disorders of children.

Tuberous sclerosis and the relation with renal angiomyolipoma. A genetic study on the clinical aspects

Renal angiomyolipomas were present in 23 out of a series of 38 patients with proven tuberous sclerosis (60.5%). Multiplicity and bilateral localization of combined renal angiomyolipomas were important differences between this category and the isolated, usually solitary, angiomyolipomas. One of the parents of a patient with tuberous sclerosis had small renal angiomyolipomas without signs of tuberous sclerosis. This indicates that renal angiomyolipomas might be a forme fruste of tuberous sclerosis. Two patients with suspected isolated renal angiomyolipomas proved to have tuberous sclerosis. From this study we can conclude that multiple angiomyolipomas, or a combination of a single renal hamartoma with one of the signs suggestive of tuberous sclerosis, warrant a thorough examination to exclude tuberous sclerosis.

Genetic aspects of tuberous sclerosis in the west of Scotland

Complete ascertainment of tuberous sclerosis was attempted in the west of Scotland (population 2,763,000). A total of 101 patients was identified, giving an overall minimum prevalence of 1 in 27,000, but for children under 10 years of age the minimum prevalence was 1 in 12,000. Both parents of 84 of the ascertained cases were assessed for signs of tuberous sclerosis. In 51 pairs of parents no evidence of the condition was seen, indicating that up to 60% of the cases were new mutations. The mutation rate was estimated at 2.5 X 10(-5) mutations per gene per generation. Analysis of parental ages for the new mutations did not show a significant age effect. Thirty-five patients occurred in 13 families containing other affected subjects. The pattern of inheritance was consistent with an autosomal dominant trait in these families. In one sibship, non-penetrance or gonadal mosaicism resulted in affected sibs with normal parents. Of two further sibships where non-penetrance was suspected, one was shown to represent a single new mutation in monozygotic twins and the other to involve non-paternity.

Biology of hypopigmentation

A review of the basics of pigment cell biology is followed by a discussion of the characteristics of several disorders of hypopigmentation. By determining such features as inheritance pattern, time of onset (congenital, childhood, adulthood), natural history (stable vs progressive), type of pigment loss (diffuse or circumscribed), distribution of lesions (generalized vs localized), degree of pigment loss (incomplete or complete), number of melanocytes, if any, in biopsy specimens of affected areas, type of melanocytic dysfunction, and associated inflammation or infection, one can classify the disorders of hypopigmentation. The proposed pathophysiology for each disorder of hypomelanosis is presented.

Tuberous sclerosis: a new estimate of prevalence within the Oxford region

Within the counties administered by the Oxford Regional Health Authority (population 2 328 100) the prevalence of tuberous sclerosis was estimated as 1 in 29 900 for persons under 65 years of age. For the population below 30 years of age the prevalence was 1 in 21 500 and for children under 5 years 1 in 15 400. Cases were ascertained through the records of the Department of Medical Genetics at Oxford and the Tuberous Sclerosis Association of Great Britain and also by a questionnaire sent to selected consultants within the region. A previous estimate of prevalence within the region was 1 in 100 000. This study suggests that the prevalence at birth might be even higher than 1 in 15 000.

tuberous sclerosis: hydroxyproline content in urine and tissues

To elucidate the nature of an overabundance of collagen seen on microscopic examination in tuberous sclerous (TS), the hydroxyproline content in tissues and urine was determined. TS tissues of 5 patients were obtained on necropsy or plastic surgery. Urine was collected from 10 patients with TS and 19 controls. Tumors in kidney, pancreas, lung and heart but not brain contained more hydroxyproline than the surrounding tissues. In brain with the lowest hydroxyproline content, the tumor showed reduced hydroxyproline compared to normal. Collagen sheet in TS skin and shagreen patch showed the same hydroxyproline content as control skin. Th urinary hydroxyproline: creatinine ratios of the patients with TS were all higher than those in age-matched controls with or without anticonvulsant treatment except for congenital muscular dystrophy. The higher content of hydroxyproline in several affected tissues and urine of patients with TS might indicate that an increase in collagen synthesis occurs in TS.