Syndrome of amelogenesis imperfecta, nephrocalcinosis, impaired renal concentration, and possible abnormality of calcium metabolism

We describe a brother and sister with amelogenesis imperfecta, nephrocalcinosis and impaired renal concentrating ability. This is the second sibship reported, further substantiating autosomal recessive inheritance of this condition. There is lack of enamel, lifelong nocturnal enuresis, progressive punctate nephrocalcinosis, and decreased calcium and phosphate excretion over 24 hours and after an acute load. Increased serum osteocalcin and decreased urine delta-carboxyglutamic acid suggest involvement of vitamin K-dependent calcium binding proteins, although this may represent a secondary finding. No other evidence of abnormal calcium metabolism was found. Renal function is stable in the early teens, but the previously reported patients went on to renal failure.

The questionable relation between cochlear pigmentation and noise-induced hearing loss

Some evidence has suggested that susceptibility to noise-induced hearing loss may be inversely proportional to the amount of melanin in the cochlea. However, published data have not been consistent in demonstrating this relation, and some results may be contaminated by lack of genetic control in experimental animals. In this investigation, noise-induced hearing loss was evaluated in pigmented and albino C57BL/6J mice that differed only in their ability to produce melanin. Surface-recorded electric responses to sound were used to assess auditory sensitivity. Results indicated no difference between the two groups either in pre-exposure thresholds or in magnitude of noise-induced threshold shift.

Diagnosis of late infantile neuronal "ceroid-lipofuscinosis" from histochemical and ultrastructural changes in dental pulp

Sections of dental pulp were removed from a tooth of a boy 3 years 10 months of age with myoclonic seizures. When stained with hematoxylin and eosin, these sections showed eosinophilic inclusions. Ultrastructurally, these inclusions were large cytosomes filled with whorls of electron-opaque substance. The opaque material consisted of bilaminate strands, approximately 15 nm in diameter, arranged in a curvilinear pattern compatible with that seen in the late infantile form of "ceroid-lipofuscinosis." Most histochemical staining reactions were compatible with ceroid or lipofuscin, with the exception of the diamine silver reaction. Late infantile ceroid-lipofuscinosis represents another disease in which asymptomatic accumulation of storage material occurs in the dental pulp.

Combined chemical and electron microscopic studies of pheomelanosomes in human red hair

This study clarified the fine structure of pheomelanosomes in human red hair by quantifying the contents of pheomelanin and eumelanin and by identifying the fine structure of melanocytes and melanosomes based on their melanogenesis type in follicles. Out of 5 red-haired subjects, 3 were found to exhibit pheomelanogenesis in follicles, while the remaining 2 were found to have a mixed type melanogenesis of pheomelanin and eumelanin. Melanocytes in the pheomelanic follicles contained spherical melanosomes which revealed sequences of development identical to those seen in the pheomelanosomes of mice and guinea pigs. In contrast, the follicles of mixed type melanogenesis contained 2 different populations of melanocytes, i.e., one with synthesis of spherical melanosomes such as seen in the pheomelanic follicles and the other with synthesis of ellipsoidal-lamellar (filamentous) granules of eumelanosome form. It was concluded that (a) visual differentiation of hair color does not always reflect the melanogenesis type in human red hair, (b) chemical analysis of melanogenesis type corresponds well to the fine structural differentiation of eumelanosomes and pheomelanosomes, and (c) human pheomelanosomes are spherical granules with microvesicular (vesiculoglobular) and proteinaceous matrices on which melanin deposition is spotty and granular.

Auditory system abnormalities in human albinos

Auditory abnormalities were evaluated in human albinos using temporary threshold shift and dichotic listening tasks. Albinos exhibited a greater temporary threshold shift than did normally pigmented individuals after exposure to a fatiguing tone. In the dichotic listening task, albinos demonstrated a significantly larger right ear advantage than normally pigmented individuals. These results support earlier work indicating that hemispheric asymmetries are present in a albino auditory system and suggest that abnormalities may be present at the cochlear level as well.

Tyrosinase subcellular distribution and kinetic parameters in wild type and C-locus mutant C57BL/6J mice

The distribution and kinetic parameters of tyrosinase (EC 1.14.-18.1) from anagen hair follicles of the C57BL/6J mouse and several c-locus mutants were investigated. The results showed that c-locus mutations not only influenced the total tyrosinase activity, but the subcellular distribution as well. The kinetic parameters of tyrosinase were not influenced by the pigment mutations, suggesting that the mutations were not influencing the structure of the enzyme.

Platelet aggregation independent of ADP release or prostaglandin synthesis in patients with hermansky-Pudlak syndrome

Platelets from patients with the Hermansky-Pudlak (HPS) syndrome are deficient in the storage pool of adenine nucleotides and serotonin. As a result, the storage pool deficient (SPD) platelets develop only single waves of clumping when stimulated by threshold concentrations of aggregating agents which cause irreversible, biphasic aggregation of normal platelets. Yet, patients with HPS either have no bleeding problems or only mild symptoms. In the present study we have evaluated the importance of prostaglandin synthesis and secretion to the irreversible aggregation of HPS platelets. Results of the study demonstrate that aspirin-treated SPD platelets, which cannot form thromboxane or undergo the release reaction on stimulation by arachidonate, can still undergo irreversible aggregation in response to thrombin and ADP if treated first with epinephrine. A mechanism of membrane modulation mediated by alpha-adrenergic receptors cooperatively linked to the endoperoxide and thromboxane receptor can secure irreversible aggregation of normal or abnormal platelets despite absence of secretion and prostaglandin synthesis.

Auditory brainstem anomalies in human albinos

Brainstem auditory evoked potentials recorded from human albinos indicate significant hemispheric asymmetry. The asymmetry is symptomatic of differences between decussated and nondecussated auditory pathways in albino and pigmented humans at approximately the level of the superior olivary nuclei. Abnormal decussation of auditory pathways in albinos probably coincides with known visual system anomalies.

Taurodontism, an isolated trait associated with syndromes and X-chromosomal aneuploidy

A review of the literature on teeth with enlarged pulp chambers and apical displacement of the bifurcation or trifurcation of roots (taurodontism) and investigation of the association of this trait with X-chromosomal aneuploidy shows that: (1) Taurodontism is not a rare trait in modern man, as indicated by the majority of recent reports, but occurs in approximately 2.5% of adult Caucasians. (2) Taurodontism occurs in syndromes, particularly in those having an ectodermal defect. (3) Among 12 patients showing taurodontic teeth radiographically, all had normal karyotypes. (4) Among 12 patients showing various combinations of X-chromosomal aneuploidy, 11 had taurodontic molars. (5) Patients with a female habitus and X-chromosomal aneuploidy as well as patients with a male habitus and X-chromosomal states have taurodontic teeth. (6) There is no simple association of the degree of taurodontism and the number of X chromosomes, but, in general, patients with the more severe forms of the trait--meso- or hypertaurodontism--are more likely to have X-chromosomal aneuploidy. While taurodontism may be viewed as an extension of a continuous trait of pulp chamber size, the extreme shape may arise when conditions disturbing the epithelial-derived root sheath produce a generalized amplified instability of development, as has been suggested from tissue culture studies of X-chromosomal aneuploid cells.

Albinism in Nigeria with delineation of new recessive oculocutaneous type

Seventy-nine Nigerian oculocutaneous albinos were investigated. Fifty-six had typical tyrosinase-positive albinism (TPA) and 23 had brown albinism (BA), a new oculocutaneous type. The TPA were characterized by localized but no generalized skin pigment, yellow hair, blue to brown irides, nystagmus, and reduced or absent retinal pigment. Localized skin pigment included freckles and lentigines. The iris and skin pigment were the result of the slow accumulation of pigment with age as both were found in older individuals. The most severe skin changes were premalignant keratoses and squamous cell carcinoma of the skin, and the skin malignancies were the major factor in limiting the lifespan for TPA. The BA were characterized by generalized light brown skin pigment, light brown hair, blue to brown irides, nystagmus, and reduced retinal pigment. There was little accumulation or change of pigment in the eyes or skin with age. The generalized light skin pigment was effective in reducing sensitivity to solar radiation and very few BA had premalignant keratoses. Pedigree analysis for BA suggested on autosomal recessive inheritance pattern.

Concurrence of anorexia nervosa and yellow mutant albinism

A review of published clinical reports shows that anorexia nervosa has been found in association with several genetic anomalies, principally gonosomal aneuploidy. An additional, and unique, association is described here: a case of anorexia nervosa in a patient with the yellow mutant form of oculocutaneous albinism and no other apparent chromosomal abnormalities. While the concurrence of these two disorders in a single person is apparently a chance phenomenon, our review of experimental publications shows that feeding disturbances also occur in yellow mutant mice. Such complementary findings suggest the need for continuing investigation of the genetic foundations of eating behaviour.

The presence of Candida albicans in hereditary benign intraepithelial dyskeratosis. An ultrastructural observation

Specimens taken from the buccal mucosa of two patients with hereditary benign intraepithelial dyskeratosis (HBID) were studied by transmission electron microscopy. The ultrastructure of epithelial tissue in HBID was previously reported. Discovery of Candida albicans in this lesion was an accidental finding. The literature on the subject was reviewed and the ultrastructural features of Candida albicans were described.

Hereditary mucoepithelial dysplasia: a disease apparently of desmosome and gap junction formation

A previously unrecognized autosomal dominant syndrome affecting oral, nasal, vaginal, urethral, anal, bladder, and conjunctival mucosa with cataracts, follicular keratosis, nonscarring alopecia, and terminal lung disease is described in a four-generation kindred of German extraction. Severe photophobia, tearing, and nystagmus in infancy heralds the development of keratitis, corneal vascularization, and lens cataracts. Repeated corneal transplants have failed. Red, periorificial mucosal lesions involving the above structures are noted by 1 year of age and may persist throughout life. Chronic rhinorrhea and repeated upper respiratory infections frequently progress to bilateral pneumonia accompanied by loss of hair, diarrhea, occasional melena, enuresis, pyuria, and hematuria. Spontaneous pneumothorax is frequent, terminating in fibrocystic-type lung disease and cor pulmonale. Women have had repeated abnormal vaginal PAP smears. Histologically the mucosal epithelium shows dyshesion, thinning of the epithelial layer, and dyskeratosis. Mucosal PAP smears show lack of epithelial maturation, cytoplasmic vacuoles and inclusions, and individual cell dyskeratosis. Histochemically there is a lack of cornification and keratinization. Ultrastructural studies show lack of keratohyalin granules, a paucity of desmosomes, intercellular accumulations, cytoplasmic vacuolization, and formation of bands and aggregates of filamentous fibers and structures in the cytoplasm resembling desmosomes and gap junctions. The condition is probably a panepithelial cell defect of desmosomal and gap junction structure most prominently affecting mucosal epithelia associated with an increased susceptibility to a variety of adventitious organisms.

Chromosome breaks and sister chromatid exchanges in albinos in Nigeria

The prevalence of squamous cell carcinoma of the skin in albinos reaches approximately 90% in patients over 20 years of age in the vicinity of Enugu, Nigeria. Chromosome breaks and sister chromatid exchanges (SCE) were evaluated in tyrosinase-positive oculocutaneous albinos and pigmented controls of Ibo extraction who were life-long residents of Nigeria. No difference in the frequency of chromosomal breaks in 14 albinos compared to 6 pigmented controls, and no differences in the frequency of SCE in 9 albinos compared to 3 controls could be detected. Increased chromosomal abnormalities in lymphocytes do not appear to be assoicated with albinism or fulminating skin cancer present in albinos in the tropics.

Clinical, histologic, cytologic, and ultrastructural characteristics of the oral lesions from hereditary mucoepithelial dysplasia. A disease of gap junction and desmosome formation

Hereditary mucoepithelial dysplasia is an autosomal, dominantly inherited disorder affecting all of the orificial mucosa with cataracts, follicular keratosis of skin, nonscarring alopecia, bouts of pneumonia, spontaneous pneumothorax, and terminal cor pulmonale. The oral lesion is a fiery red, flat or micropapillary-appearing mucosa most frequently involving the gingiva and hard palate. All oral and pharyngeal mucosa may be involved, however. Red scrotal mucosa of the tongue is common. Histologically, the oral mucosa shows a lack of cornified and keratinized cells, a decrease in the thickness of the epithelial cell layer, dyshesion, and dyskeratosis. Papanicolaou smears show lack of epithelial cell maturation, poikilocytosis, anisocytosis, large paranuclear cytoplasmic vacuoles, and cytoplasmic strand-shaped inclusions. Ultrastructural features include a paucity of desmosomes, intercellular accumulations of amorphous material, cytoplasmic vacuoles, and paranuclear lesions with strands of material resembling gap junctions and desmosomes. The condition most likely represents a basic defect in gap junction and desmosome formation.

Odontodysplasia. Report of three cases with vascular nevi overlying the adjacent skin of the face

Three cases of odontodysplasia are described, and the literature is reviewed with reference to proposed etiologic mechanisms underlying the pathogenesis of the disorder. The distribution of affected teeth in all four quadrants of one patient is offered as evidence against a somatic mutation as an etiologic mechanism. As infants all three patients had vascular nevi in the facial skin overlying the area where defective teeth developed. Three cases from the literature involved similar vascular lesions. Hypoplastic teeth radiographically similar to odontodysplastic teeth occur in the linear sebaceous nevus syndrome. These findings strongly suggest that local vascular defects are involved in the pathogenesis of odontodysplasia.

Visual system anomalies in human ocular albinos

Visually evoked potentials recorded from two types of human ocular albinos demonstrated significant hemispheric asymmetry following monocular stimulation. The asymmetry is indicative of disorganization of retinogeniculostriate projections similar to that reported for mammals with total albinism. Abnormal optic projections are associated with lack of ocular pigment and are not associated with any specific generalized pigment defect.

Clinical, genetic, and histologic features of the trichoonychodental (TOD) syndrome

A syndrome of scanty, fine, curled hair, thin dysplastic nails, taurodontic molars, hypoplastic-hypomature enamel, dysplasia of dentin, and hypohidrosis segregating as an autosomal dominant trait is described in a Japanese family. The patients received repeated doses of tetracycline during odontogenesis which fortuitously assisted in interpreting the pathogenesis of the dentin defect. The condition was previously described as familial congenital ectodermal dysplasia by Westerholm and as odontogenesis imperfecta by Siirilä and Heikinheimo. It is suggested that the name trichoonychodental (TOD) syndrome is a better descriptive term for the condition.

Autosomal recessively inherited ocular albinism. A new form of ocular albinism affecting females as severely as males

A new form of ocular albinism, autosomal recessively inherited ocular albinism (AROA), was studied in seven females and two males from five unrelated Caucasian kindreds. Affected patients have the impaired vision, translucent irides, congenital nystagmus, photophobia, albinotic fundi with hypoplasia of the fovea, and strabismus that are also found in X-linked ocular albinism (XOA). Unlike XOA, however, this form of ocular albinism is inherited as an autosomal recessive trait, with females affected as severely as males. Obligate heterozygotes of AROA lack the ocular abnormalities that are present in females heterozygous for XOA. Also, skin and hairbulb biopsy specimens do not reveal any abnormalities in patients with AROA, whereas giant pigment granules are found in patients heterozygous and hemizygous for XOA. The recognition of this disorder is imperative for proper diagnosis and responsible genetic counseling.