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

Phakomatoses

Phakomatoses present with characteristic findings on the skin, central or peripheral nervous system, and tumors. Neurofibromatosis type 1 is the most common syndrome and is characterized by Café-au-lait macules, intertriginous freckling, Lisch nodules, and tumors including neurofibromas, malignant peripheral nerve sheath tumors, and gliomas. Tuberous Sclerosis Complex is characterized by benign hamartomas presenting with hypomelanotic macules, shagreen patches, angiofibromas, confetti lesions and tumors including cortical tubers, subependymal nodules, subependymal giant cell astrocytomas and tumors of the kidney, lung, and heart. Managing these disorders requires disease specific supportive care, tumor monitoring, surveillance for selected cancers, and treatment of comorbid conditions.

A systematic review on the burden of illness in individuals with tuberous sclerosis complex (TSC)

Objective

This review will summarize current knowledge on the burden of illness (BOI) in tuberous sclerosis complex (TSC), a multisystem genetic disorder manifesting with hamartomas throughout the body, including mainly the kidneys, brain, skin, eyes, heart, and lungs.

Methods

We performed a systematic analysis of the available literature on BOI in TSC according to the PRISMA guidelines. All studies irrespective of participant age that reported on individual and societal measures of disease burden (e.g. health care resource use, costs, quality of life) were included.

Results

We identified 33 studies reporting BOI in TSC patients. Most studies (21) reported health care resource use, while 14 studies reported quality of life and 10 studies mentioned costs associated with TSC. Only eight research papers reported caregiver BOI. Substantial BOI occurs from most manifestations of the disorder, particularly from pharmacoresistant epilepsy, neuropsychiatric, renal and skin manifestations. While less frequent, pulmonary complications also lead to a high individual BOI. The range for the mean annual direct costs varied widely between 424 and 98,008 International Dollar purchasing power parities (PPP-$). Brain surgery, end-stage renal disease with dialysis, and pulmonary complications all incur particularly high costs. There is a dearth of information regarding indirect costs in TSC. Mortality overall is increased compared to general population; and most TSC related deaths occur as a result of complications from seizures as well as renal complications. Long term studies report mortality between 4.8 and 8.3% for a follow-up of 8 to 17.4 years.

Conclusions

TSC patients and their caregivers have a high burden of illness, and TSC patients incur high costs in health care systems. At the same time, the provision of inadequate treatment that does not adhere to published guidelines is common and centralized TSC care is received by no more than half of individuals who need it, especially adults. Further studies focusing on the cost effectiveness and BOI outcomes of coordinated TSC care as well as of new treatment options such as mTOR inhibitors are necessary.

Spectrum of orocutaneous disease associations: Genodermatoses and inflammatory conditions

The oral cavity and cutaneous organ systems share a close embryologic origin. Therefore, there are numerous dermatologic conditions presenting with concomitant oral findings of which the dermatologist must be aware. The second article in this continuing medical education series reviews inflammatory orocutaneous conditions and a number of genodermatoses. It is essential for dermatologists to be familiar with oral cavity manifestations associated with dermatologic diseases for prompt diagnosis, management, and appropriate referral to stomatology and dentistry.

"Pitted" lesions in dermatology

Cutaneous pitting, dimpling, or depressions are frequently dealt with in clinical practice. Such lesions may be primary manifestations of a disorder or develop as secondary changes during the course of the disease. Cutaneous pitting may be a manifestation of certain genodermatoses and internal disorders when it serves as a marker of such conditions. This article describes various types of pitted lesions affecting the ectodermal structures (skin, nails, and teeth) and their clinical significance along with brief description of the associated conditions.

Tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects multiple organ systems and is caused by loss-of-function mutations in one of two genes: TSC1 or TSC2. The disorder can affect both adults and children. First described in depth by Bourneville in 1880, it is now estimated that nearly 2 million people are affected by the disease worldwide. The clinical features of TSC are distinctive and can vary widely between individuals, even within one family. Major features of the disease include tumours of the brain, skin, heart, lungs and kidneys, seizures and TSC-associated neuropsychiatric disorders, which can include autism spectrum disorder and cognitive disability. TSC1 (also known as hamartin) and TSC2 (also known as tuberin) form the TSC protein complex that acts as an inhibitor of the mechanistic target of rapamycin (mTOR) signalling pathway, which in turn plays a pivotal part in regulating cell growth, proliferation, autophagy and protein and lipid synthesis. Remarkable progress in basic and translational research, in addition to several randomized controlled trials worldwide, has led to regulatory approval of the use of mTOR inhibitors for the treatment of renal angiomyolipomas, brain subependymal giant cell astrocytomas and pulmonary lymphangioleiomyomatosis, but further research is needed to establish full indications of therapeutic treatment. In this Primer, we review the state-of-the-art knowledge in the TSC field, including the molecular and cellular basis of the disease, medical management, major knowledge gaps and ongoing research towards a cure.

Tuberous sclerosis complex diagnosed from oral lesions

CONTEXT

Tuberous sclerosis complex (TSC) is a genetic disease in the group known as neurocutaneous syndromes, with dominant autosomal inheritance. It is characterized by skin and adnexal lesions and central and peripheral nervous system tumors, with neurological and psychiatric findings. It may affect the heart, kidneys, eyes, face, bones, lungs, stomach and dentition.

CASE REPORT

We present the case of a 66-year-old man with dermatological signs that included hypopigmented maculae, confetti-like lesions, shagreen plaque, angiofibromas on nasolabial folds, neck and back, nail dystrophy and periungual fibromas on fingers and toes. An electroencephalogram produced normal results, but magnetic resonance imaging showed a nodular image measuring 1.2 x 1.0 cm close to the Monro foramen, which was similar to cerebral parenchyma and compatible with a subependymal giant-cell astrocytoma. A conservative approach was taken, through control imaging examinations on the lesion for seven years, with absence of any expansive process or neurological symptoms. Abdominal ultrasonography revealed a solid, heterogenic and echogenic mass with a calcified focus, measuring 4.6 x 3.4 cm, in the rightkidney, compatible with angiomyolipoma. The patient was treated by means of complete nephrectomy because of malignant areas seen on histopathological examination and died one month after the procedure. This case report illustrates the importance of oral clinical findings such as dental enamel pits and angiofibromas in making an early diagnosis of TSC, with subsequent screening examinations, treatment and genetic counseling.

Systemic disorders and their influence on the development of dental hard tissues: a literature review

OBJECTIVES

This report highlights the influence of a number of disorders with systemic physiological effects that impact on the development of dental hard tissues. It focuses in particular, on the pathological effects of systemic conditions with less well recognised, but no less important, impacts on dental development. Such conditions, include cystic fibrosis, HIV/AIDS, leukaemia, Alstrom syndrome, hypophosphatasia, Prader-Willi syndrome, Tricho-dento-osseous syndrome, tuberous sclerosis, familial steroid dehydrogenase deficiency and epidermolysis bullosa. These, along with developmental and environmental causes of enamel and dentine defects, are discussed and the possible aetiology of such effects are proposed. Furthermore, the dental management and long-term dental care of these patients is outlined.

SOURCES

MEDLINE/PubMed.

CONCLUSIONS

Enamel and dentine defects can present with a wide spectrum of clinical features and may be caused by a variety of factors occurring throughout tooth development from before birth to adulthood. These may include host traits, genetic factors, immunological responses to cariogenic bacteria, saliva composition, environmental and behavioural factors and systemic diseases. These diseases and their spectrum of clinical manifestations on the organs affected (including the dentition) require an increased knowledge by dental practitioners of the disease processes, aetiology, relevant treatment strategies and prognosis, and must encompass more than simply the management of the dental requirements of the patient. It is important that the impact of the disease and its treatment, particularly in respect of immunosuppression where dental interventions may become life-threatening, is also taken into consideration.

[Skin and teeth]

Skin and teeth not only share several characteristics in their development but also have a similar ontogenetic origin from the ectoderm. Thus, numerous congenital diseases, such as genetic, infectious, inflammatory, and immune disorders affect both skin and teeth. Particularly skin diseases are often identified by the synopsis of systemic symptoms. The understanding and appreciation of dental abnormalities guides dermatologists in the diagnosis and identification of syndromes as well as in finding an optimal therapy.

Tuberous sclerosis

Tuberous sclerosis is a genetic multisystem disorder characterised by widespread hamartomas in several organs, including the brain, heart, skin, eyes, kidney, lung, and liver. The affected genes are TSC1 and TSC2, encoding hamartin and tuberin respectively. The hamartin-tuberin complex inhibits the mammalian-target-of-rapamycin pathway, which controls cell growth and proliferation. Variations in the distribution, number, size, and location of lesions cause the clinical syndrome to vary, even between relatives. Most features of tuberous sclerosis become evident only in childhood after 3 years of age, limiting their usefulness for early diagnosis. Identification of patients at risk for severe manifestations is crucial. Increasing understanding of the molecular abnormalities caused by tuberous sclerosis may enable improved management of this disease.

Zahnanomalien bei Genodermatosen

Sowohl Haare, Nägel und Schweißdrüsen als auch die Zähne stellen ektodermale Anhangsgebilde dar. So ist es verständlich, warum Mutationen in Genen, welche die Embryogenese steuern, oft gleichzeitig die Haut und die Zähne in Mitleidenschaft ziehen. Autosomal dominante kutaneodentale Syndrome sind tuberöse Sklerose, tricho-dento-ossäres Syndrom, AEC-Syndrom, EEC-Syndrom, onychodentales Syndrom Typ Witkop, Amelogenesis imperfecta mit distaler Onycholyse und Böök-Syndrom. Autosomal rezessive Genodermatosen mit Zahndefekten sind Papillon-Lefèvre-Syndrom, GAPO-Syndrom, Steijlen-Syndrom und junktionale Epidermolysis bullosa. X-gebundene männlich-letale Syndrome mit Haut- und Zahnsymptomatik sind Incontinentia pigmenti, Goltz-Syndrom und OFD1-Syndrom. Unter den X-gebundenen nichtletalen Phänotypen ist das Christ-Siemens-Touraine-Syndrom wohlbekannt, während die ektodermale Dysplasie Typ Zonana eine erst kürzlich beschriebene Krankheitsentität, verursacht durch „hypomorphe“ Mutationen im NEMO-Gen, darstellt. Da auch diese Krankheit mit einer ausgeprägten Hypohidrose einhergeht, taugt die Bezeichnung „X-chromosomale hypohidrotische ektodermale Dysplasie“ heute nicht mehr zur Kennzeichnung des Christ-Siemens-Touraine-Syndroms.

Tuberous sclerosis complex: advances in diagnosis, genetics, and management

Tuberous sclerosis complex (TSC) is an autosomal dominant multisystem neurocutaneous syndrome characterized by the development of multiple hamartomas distributed throughout the body, skin, brain, heart, kidneys, liver, and lungs. Two-thirds of patients represent sporadic mutations. The classic triad is seizures, mental retardation, and cutaneous angiofibromas. However, the full triad occurs in only 29% of patients; 6% of them lack all three of them. Two tumor suppressor genes responsible for TSC have been identified: TSC1 gene on chromosome 9 and TSC2 on chromosome 16. This article highlights the most recent significant advances in the diagnosis and genetics of TSC, along with a discussion on the limitations and the usefulness of the revised 1998 clinical criteria for the tuberous sclerosis complex. The "ash leaf" macule often comes in other shapes, such as round; most are polygonal, usually 0.5 cm to 2.0 cm in diameter, resembling a thumbprint. Since the death of its describer, Thomas Fitzpatrick, we call each a "Fitzpatrick patch." Special attention is paid in this work to TSC treatment options, including therapeutic trials with rapamycin, also known as sirolimus.

LEARNING OBJECTIVE

After completing this learning activity, participants should familiar with tuberous sclerosis complex, its cutaneous signs and systemic findings stratified by patient age, its genetics, and the potential for meaningful therapeutic intervention.

Oral findings in 58 adults with tuberous sclerosis complex

BACKGROUND

Gingival fibromas and dental pitting are among the diagnostic criteria for tuberous sclerosis complex (TSC).

OBJECTIVE

Our goal was to document the oral findings in 58 adult patients with TSC.

RESULTS

Forty patients (69%) had oral fibromas, appearing mostly on the attached or interdental gingiva. Other oral mucosal sites with fibromas included buccal and labial mucosa, the superior labial frenulum, palate, and tongue. In all, 56 patients (97%) had multiple dental enamel pits.

LIMITATIONS

This case series comprised predominantly adult women with TSC and lymphangioleiomyomatosis.

CONCLUSIONS

Oral fibromas in TSC are mostly, but not exclusively, gingival. Dental pits are present in nearly all patients. The multiple oral papules in TSC may appear similar to those observed in Cowden syndrome, Birt-Hogg-Dubé syndrome, and rarely in multiple endocrine neoplasia type 1.

Oral manifestations of genodermatoses

Many genodermatoses have distinct oral features that may help identify or confirm a genetic diagnosis. Oral features of the disorders described here are summarized in Table 1. These conditions provide clear examples of rapid progress in the field of genetic technology relevant to patient care. Less than a decade ago, the exact genetic locus of most of these disorders was unknown. Today, for many of these disorders, the exact location of the disease-causing mutation is known and clinical genetic testing is available for patients. This information has impact not only for genetic counseling and anticipatory medical care, but also provides insight into the mechanisms of disease. How this rapid progress will impact care, and ultimately treatment of patients, remains to be seen.

Overgrowth of oral mucosa and facial skin, a novel feature of aspartylglucosaminuria

Aspartylglucosaminuria (AGU) is a lysosomal storage disorder caused by deficiency of aspartylglucosaminidase (AGA). The main symptom is progressive mental retardation. A spectrum of different mutations has been reported in this disease, one missense mutation (Cys163Ser) being responsible for the majority of Finnish cases. We were able to examine 66 Finnish AGU patients for changes in the oral mucosa and 44 of these for changes in facial skin. Biopsy specimens of 16 oral lesions, 12 of them associated with the teeth, plus two facial lesions were studied histologically. Immunohistochemical staining for AGA was performed on 15 oral specimens. Skin was seborrhoeic in adolescent and adult patients, with erythema of the facial skin already common in childhood. Of 44 patients, nine (20%) had facial angiofibromas, tumours primarily occurring in association with tuberous sclerosis. Oedemic buccal mucosa (leucoedema) and gingival overgrowths were more frequent in AGU patients than in controls (p<0.001). Of 16 oral mucosal lesions studied histologically, 15 represented fibroepithelial or epithelial hyperplasias and were reactive in nature. Cytoplasmic vacuolisation was evident in four. Immunohistochemically, expression of AGA in AGU patients' mucosal lesions did not differ from that seen in corresponding lesions of normal subjects. Thus, the high frequency of mucosal overgrowth in AGU patients does not appear to be directly associated with lysosomal storage or with alterations in the level of AGA expression.

Diagnosis and management of tuberous sclerosis complex

Tuberous sclerosis complex (TSC) is an autosomal-dominant neurocutaneous disorder with a high spontaneous mutation rate. Understanding of this disorder has greatly increased in recent years. Two chromosomal loci can produce the TSC phenotype: 9q34 and 16p13. These appear to code for proteins that have a tumor suppressor function. TSC results in hamartomas that affect various organ systems, most commonly brain, skin, heart, and kidney. Previously thought to consist of intractable seizures, facial angiofibromas, and dementia, increasing numbers of persons with less severe involvement have been identified. Diagnostic criteria, various types of lesions, and medical management are reviewed.