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This chapter discusses systemic inherited disorders with dental involvement. It discusses acroosteolysis, amelocerebrohypohidrosis syndrome, cryptodontic brachymetacarpalia, hypodontia and nail dysgenesis, hypophosphatasia, hypophosphatemic vitamin D-resistant rickets, hypoplastic-hypocalcified enamel, onycholysis, functionali hypohidrosis, incontinentia pigmenti, oculodentoosseous dysplasia, otodental syndrome, pseudohypoparathyroidism and pseudo-pseudohypoparathyroidism, and rothmund−thomson syndrome among others. Acroosteolysis, which has an autosomal dominant mode of inheritance, is characterized by short stature, disintegration of the terminal phalanges of fingers and toes, abnormal skull shape, and premature loss of teeth. The Amelocerebrohypohidrosis syndrome is characterized by the following features: (1) severe seizures, (2) progressive mental retardation, (3) muscular spasticity, (4) hypohidrosis, and (5) enamel hypoplasia. There is marked hypoplasia of enamel, resulting in complete absence, except for small zones of thin enamel at cervix of the tooth crowns. The enamel defect is generalized and involves all teeth in both primary and secondary dentitions.

This chapter discusses some of the various systemic inherited disorders involving oral or perioral soft tissue involvement. Acrodermatitis enteropathica is rare and is characterized by skin lesions, hair loss, nail changes, and gastrointestinal disturbances. Acrodermatitis enteropathica generally becomes manifest between three weeks and ten years of age and is only occasionally seen in adults. The lips and perioral skin are affected. Pustular formation at the angle of the mouth is almost always complicated with deep fissuring. Bloom syndrome is inherited in an autosomal recessive manner. It has an increased incidence among Jews of Eastern-European extraction. Parental consanguinity, while higher among non-Jews, is no greater among Jews, indicating the rarity of the gene among the former. The Chediak–Higashi syndrome is manifested by defective pigmentation, large eosinophilic, peroxidase-positive inclusion bodies in myeloblasts and promyelocytes of the bone marrow, neutropenia, and susceptibility to infection and malignant lymphoma. The syndrome is inherited in an autosomal recessive manner.

This chapter discusses some of the systemic inherited disorders that are associated with facial clefting. The syndrome of cleft lip-palate and congenital lip pits has been recognized for over 100 years. The condition is transmitted as an autosomal dominant condition with 80% penetrance of any component of the syndrome. The syndrome is seen with a frequency of about 1 in 75,000–100,000 live births and affects both sexes equally. The cleft lip-palate and tetraphocomelia syndrome consists of cleft lip-palate, tetraphocomelia with a reduction in digit number, exophthalmus and ocular hypertelorism, and deficient growth. The facies is characterized by ocular hypertelorism, exophthalmos, and usually bilateral cleft lip palate.

This chapter reviews single gene inheritance patterns and provides an overview of genetic counseling and oral examination. Many heritable syndromes have distinctive oral manifestations that aid the diagnostician. The chapter provides a brief review of the normal oral configuration and some of the frequent variations from normal. Two indispensable aids are needed to perform an accurate oral examination: (1) an intraoral mirror and (2) good illumination. Manifestations of inherited disorders may occur in any area of the oral cavity and therefore, a systematic approach to clinical inspection is recommended. The mouth is divided into two parts: (1) the vestibule and (2) the oral cavity proper. The vestibule is bound by the teeth and gingiva on the one side and by the buccal and labial mucosae on the other. The roof and floor of this area are known as the vestibular sulci. Within the sulcus, frenulas are normally seen in the anterior maxilla and mandible, extending from the lip to the gingival mucosa. Whitening of the oral soft tissues, generally known as leukoplakia, is also associated with some inherited disorders. Other white conditions are also frequently found. The chapter additionally presents a brief summary of some intraoral radiologie landmarks.

This chapter discusses some of the various systemic disorders involving multiple oral structures. In bird-headed dwarfism, the face is narrow with a receding mandible. The eyes are large with mild antimongoloid obliquity of the palpebral fissures, strabismus, and ocular hypertelorism. The most characteristic finding is the beak-like protrusion of the midface. The chapter discusses another disorder, cleidocranial dysplasia, which is transmitted in an autosomal dominant manner—although in less than half the cases, it arises spontaneously— caused either by mutation or a gene with poor penetrance. The cockayne syndrome is characterized by cachectic dwarfism, premature aging, mental deficiency, microcephaly, intracranial calcifications, neurological deficits, retinal pigmentary abnormalities, sensorineural deafness, and photosensitivity. The facies has a typical bird-like appearance, accentuated by a beak-like nose, sunken eyes, and prominent cheek bones.

This chapter discusses some of the various systemic inherited disorders involving the jaw bones. Apert syndrome is a form of craniosynostosis consisting of turribrachycephaly and syndactyly of hands and feet. A high-arched palate, occasionally with a marked median furrow, is frequently observed. Physical development is within normal limits. Most patients have an intelligence below normal. The cranium has a characteristic oxycephalic appearance. Carpenter syndrome consists of acrocephaly, soft-tissue syndactyly and brachymesophalangy, preaxial polydactyly and syndactyly of the toes, coxa valga and pes varus, congenital heart disease, mental retardation, hypogenitalism, mild obesity, and hernia. The syndrome is inherited as an autosomal recessive condition. Low level of intelligence is generally observed in those patients who do not die of congenital heart disease.

This chapter discusses some inherited conditions affecting only calcified dental tissue. Hereditary defects in enamel, unassociated with other generalized defects, are referred to as amelogenesis imperfect. In general, hypoplastic types of amelogenesis imperfecta are those in which the enamel has not attained a normal thickness. In enamel that has attained normal thickness, subnormal hardness differentiates hypocalcified varieties from hypomaturation amelogenesis imperfecta. Coronal dentin dysplasia is characterized by the following features: (1) amber-translucent primary teeth, (2) obliteration of primary tooth pulp chambers, (3) normally colored permanent teeth, and (4) radicular extension of pulp chamber in permanent teeth. Dentin dysplasia type II is inherited as an autosomal dominant condition. Although both dentitions are affected, the pattern is different. Primary teeth have a translucent-amber color and show obliteration of pulp chambers by abnormal dentin. These teeth closely resemble dentinogenesis imperfect type II. Dentinogenesis imperfect is characterized by the following features: (1) bluish brown teeth, (2) bulbous crowns, (3) absence of pulp chambers and canals, and (4) enamel hypoplasia (20%). The condition is inherited in an autosomal dominant mode with high penetrance.