Gingival overgrowth, congenital generalized hypertrichosis, mental retardation and epilepsy: case report and overview

Hereditary gingival fibromatosis associated with the missense mutation of the KCNK4 gene

Hereditary gingival fibromatosis (HGF) is a rare oral condition that may appear as an isolated entity or as part of a genetic disease or syndrome. Molecular and biochemical mechanisms that trigger this pathologic process are not completely understood. In this article, we present a rare case of hereditary gingival fibromatosis in conjunction with a syndromic phenotype, associated with a rare missense mutation of the KCNK4 gene. This mutation induces a change in the structure of the TRAAK channel belonging to the 2-pore potassium channels. The gain of function promoted by the mutation could represent the pathogenetic basis of gingival fibromatosis.

"Electrifying dysmorphology": Potassium channelopathies causing dysmorphic syndromes

Potassium channels are a heterogeneous group of membrane-bound proteins, whose functions support a diverse range of biological processes. Genetic disorders arising from mutations in potassium channels are classically recognized by symptoms arising from acute channel dysfunction, such as periodic paralysis, ataxia, seizures, or cardiac conduction abnormalities, often in a patient with otherwise normal examination findings. In this chapter, we review a distinct subgroup of rare potassium channelopathies whose presentations are instead suggestive of a developmental disorder, with features including intellectual disability, craniofacial dysmorphism or other physical anomalies. Known conditions within this subgroup are: Andersen-Tawil syndrome, Birk-Barel syndrome, Cantú syndrome, Keppen-Lubinsky syndrome, Temple-Baraitser syndrome, Zimmerman-Laband syndrome and a very similar disorder called Bauer-Tartaglia or FHEIG syndrome. Ion channelopathies are unlikely to be routinely considered in the differential diagnosis of children presenting with developmental concerns, and so detailed description and photographs of the clinical phenotype are provided to aid recognition. For several of these disorders, functional characterization of the genetic mutations responsible has led to identification of candidate therapies, including drugs already commonly used for other indications, which adds further impetus to their prompt recognition. Together, these cases illustrate the potential for mechanistic insights gained from genetic diagnosis to drive translational work toward targeted, disease-modifying therapies for rare disorders.

Congenital Generalized Hypertrichosis Terminalis with Gingival Hyperplasia and a Coarse Face: a Case Report

Congenital generalized hypertrichosis, in its most common form, is idiopathic. In the absence of underlying endocrine or metabolic disorders, congenital generalized hypertrichosis is rare in humans, affecting as few as one in a billion individuals and may be an isolated condition of the skin, or a component feature of other disorders or syndromes. Congenital generalized hypertrichosis terminalis is an extremely rare condition, a distinct subset of disorders with congenital hypertrichosis, presenting with excessive hair as the primary clinical feature. Congenital generalized hypertrichosis terminalis is characterized by universal excessive growth of pigmented terminal hair and often accompanied with gingival hyperplasia and/or a coarse face. Gingival hyperplasia may be delayed even until puberty. Its pathogenesis may be caused by one of the following mechanisms: conversion of vellus to terminal hairs and/or prolonged anagenetic stage, and/or increase in the number of hair follicles. Since the Middle Ages, less than 60 individuals with congenital hypertrichosis terminalis have been described, and, according to the most recent estimates, less than 40 cases were documented adequately and definitively in the literature. Recent articles identified congenital generalized hypertrichosis terminalis as a genomic disorder.

This report is a follow up of a six-year-old boy born from the first normal pregnancy of non-consanguineous parents, starting from delivery. Our investigation revealed a history of: excessive hair growth and a coarse face from birth; increased body weight with high blood pressure and gingival hyperplasia at the age of four months. The parents denied any medication or chemical intake during pregnancy, as well as a history of hypertrichosis in their families. The child had a congenital hydronephrosis of the right kidney. Ultrasound and magnetic resonance imaging revealed severe congenital hydronephrosis of the right kidney and suspicion of hypertrophy of the left adrenal gland suggestive of an adenoma. The follow up showed normal values of hormones which excluded adrenal tumor. At the age of 8 months the patient underwent right-sided nephrectomy after several urinary infections. The child was admitted again to our Clinic at the age of four years, with generalized hypertrichosis, gingival hyperplasia and a coarse face without any other pathological signs. He has had a normal intellectual development, but was extremely shy, unconfident and dependent on his mother. The relevant laboratory investigations showed normal full blood count, biochemical, hormonal test results and normal function of the single kidney. Molecular chromosome analysis revealed heterozygous deletion on chromosome 17q12 region. Prolonged follow-up with routine checkups every 6–12 months was advised, including regular outpatient appointments particularly with an endocrinologist, because of the risk of diabetes mellitus, and with a nephrologist, for control of renal function.

Laser hair removal was suggested and the patient underwent one procedure with long pulsed neodynium:yttrium-albumin-garnet laser with a wavelength of 1064 nm. The procedure was effective and well-tolerated and the treatment course is currently ongoing.

Although it is now believed that most people with congenital generalized hypertrichosis have an unknown genetic defect, up to date, a clear specific molecular abnormality has not been proved. It has been suggested that the distal portion of human chromosome 17q may contain dosage-sensitive genes that contribute to excessive hair growth.

We present a sporadic case of an extremely rare congenital generalized hypertrichosis terminalis in a six-year-old boy born to non-consanguineous parents, with gingival hyperplasia, a coarse face and congenital hydronephrosis, with heterozygous deletion on chromosomal region 17q12 consistent with his renal phenotype.

Congenital generalized hypertrichosis: the skin as a clue to complex malformation syndromes

Hypertrichosis is defined as an excessive growth in body hair beyond the normal variation compared with individuals of the same age, race and sex and affecting areas not predominantly androgen-dependent. The term hirsutism is usually referred to patients, mainly women, who show excessive hair growth with male pattern distribution.Hypertrichosis is classified according to age of onset (congenital or acquired), extent of distribution (generalized or circumscribed), site involved, and to whether the disorder is isolated or associated with other anomalies. Congenital hypertrichosis is rare and may be an isolated condition of the skin or a component feature of other disorders. Acquired hypertrichosis is more frequent and is secondary to a variety of causes including drug side effects, metabolic and endocrine disorders, cutaneous auto-inflammatory or infectious diseases, malnutrition and anorexia nervosa, and ovarian and adrenal neoplasms. In most cases, hypertrichosis is not an isolated symptom but is associated with other clinical signs including intellective delay, epilepsy or complex body malformations.A review of congenital generalized hypertrichosis is reported with particular attention given to the disorders where excessive diffuse body hair is a sign indicating the presence of complex malformation syndromes. The clinical course of a patient, previously described, with a 20-year follow-up is reported.

De Novo 17q24.2-q24.3 microdeletion presenting with generalized hypertrichosis terminalis, gingival fibromatous hyperplasia, and distinctive facial features

Generalized hypertrichosis is a feature of several genetic disorders, and the nosology of these entities is still provisional. Recent studies have implicated chromosome 17q24.2-q24.3 microdeletion and the reciprocal microduplication in a very rare form of congenital generalized hypertrichosis terminalis (CGHT) with or without gingival hyperplasia. Here, we report on a 5-year-old Egyptian girl born to consanguineous parents. The girl presented with CGHT and gingival hyperplasia for whom we performed detailed clinical, pathological, and molecular studies. The girl had coarse facies characterized by bilateral epicanthic folds, thick and abundant eyelashes, a broad nose, full cheeks, and lips that constituted the distinctive facial features for this syndrome. Biopsy of the gingiva showed epithelial marked acanthosis and hyperkeratosis with hyperplastic thick collagen bundles and dense fibrosis in the underlying tissues. Array analysis indicated a 17q24.2-q24.3 chromosomal microdeletion. We validated this microdeletion by real-time quantitative PCR and confirmed a perfect co-segregation of the disease phenotype within the family. In summary, this study indicates that 17q24.2-q24.3 microdeletion caused CGHT with gingival hyperplasia and distinctive facies, which should be differentiated from the autosomal recessive type that lacks the distinctive facies.

Clinical and genetic study of two patients with Zimmermann-Laband syndrome and literature review

Zimmermann-Laband syndrome (ZLS) is a rare MCA/MR condition mainly characterized by gingival hypertrophy, hypo/aplastic nails and distal phalanges, hypertrichosis and intellectual disability. The molecular basis of ZLS is unknown. Most patients are sporadic, although familial aggregation is also observed with different inheritance patterns. We report on two unrelated children with full-blown characteristics of ZLS. Remarkable variability in expression included severity of neurocognitive involvement and extent of appendicular and facial features. In both, comparative genome hybridization array at a ~ 75 Mb resolution resulted negative, while aminoacid metabolic screening revealed high plasma levels of hypoxanthine and xanthine in one. Literature review identified 50 previously published patients (27 females, 23 males), including 14 familial, clustered in four pedigrees, and 37 sporadic. Tabulation of clinical features confirmed the core phenotype and identified developmental delay as the unique major clinical problem (occurring in 40% of the cases) with a moderately high risk of epilepsy (13%). Segregation analysis in the 20 sporadic patients with available data on healthy sibs and a single pedigree with affected sibs was significantly in contrast with an autosomal recessive mutation. An autosomal dominant mutation with high mutation rate and rare instances of germinal mosaicism seems the most likely inheritance pattern. This work may represent a starting point for future molecular studies aimed at identifying the molecular basis of ZLS.

Idiopathic gingival hyperplasia: a case report with a 17-year followup

This is a case report of a patient with idiopathic gingival hyperplasia and an undiagnosed genetic disorder that demonstrated static encephalopathy, mental retardation, developmental delay, seizures, hypotonia, and severe gingival hypertrophy. The clinical dental management and attempts to obtain a genetic diagnosis are described.

Expanding the phenotype of gingival fibromatosis-mental retardation-hypertrichosis (Zimmermann-Laband) syndrome

Zimmermann-Laband syndrome (ZLS) is a rare disorder characterized by gingival fibromatosis, hypertrichosis, intellectual disability, and absence and/or hypoplasia of the nails or terminal phalanges of the hands and feet. The syndromic features of ZLS are highly variable and can overlap with other entities featuring gingival fibrosis. This study describes a patient with ZLS with novel findings, including colpocephaly, hemivertebra, polydactyly, hyperpigmentation, and hemihyperplasia. Thus, the present report expands the phenotypic spectrum of this uncommon syndrome.

Current concepts on gingival fibromatosis-related syndromes

Gingival fibromatosis is a rare, benign, slowly-growing fibrous overgrowth of the gingiva, with great genetic and clinical heterogeneity. Gingival fibromatosis/overgrowth can be inherited as an isolated trait (hereditary gingival fibromatosis) and/or as a component of a syndrome, or it can be drug induced. As a clinical manifestation of a syndrome, gingival fibromatosis is usually associated with generalized hypertrichosis, mental retardation, or epilepsy. Gingival fibromatosis and its related syndromes are mainly inherited in an autosomal-dominant manner, but autosomal-recessive inheritance has also been reported. Clinical syndromic presentation includes Zimmermann-Laband syndrome, Ramon syndrome, Rutherford syndrome, Cowden syndrome, Cross syndrome, Göhlich-Ratmann syndrome, Avani syndrome, and I-cell disease. However, a phenotypic overlap has been suggested, as many combinations of their systemic manifestations have been reported. Treatment of choice is usually gingivectomy with gingivoplasty. Before any therapy, clinical practitioners must take into consideration the clinical course of a particular syndrome and every possible functional and esthetic disorder.

Cherubism combined with epilepsy, mental retardation and gingival fibromatosis (Ramon syndrome): a case report

Cherubism is an inherited, autosomal dominant disorder that characteristically affects the jaws of children. The disease typically manifest as a bilateral swelling with associated submandibular lymph node enlargements and usually regresses as age advances. The disease is microscopically indistinguishable from other giant cell lesions and is essentially a clinical diagnosis. The association of cherubism with gingival fibromatosis, epilepsy, mental retardation, stunted growth, and hypertrichosis is referred as Ramon syndrome. We report a case of Ramon syndrome in an 8 year old girl.