Hypophosphataemic Rickets Secondary to Raine Syndrome: A Review of the Literature and Case Reports of Three Paediatric Patients’ Dental Management

Abstract

Raine Syndrome (RS) also referred to as lethal osteosclerotic bone dysplasia describes an exceptionally rare autosomal recessive disorder with an estimated prevalence of <1 in 1,000,000. Endocrinological manifestations such as hypophosphataemic rickets depict a recent finding within the phenotypic spectrum of nonlethal RS. The dental sequelae of hypophosphataemic rickets are significant. Spontaneous recurrent abscesses on noncarious teeth result in significant odontogenic pain and multiple dental interventions. The dental presentations of nonlethal RS are less widely described within the literature. Amelogenesis Imperfecta (AI), however, was recently postulated as a key characteristic. This article presents the dental manifestations and extensive restorative and oral surgical intervention of three siblings with hypophosphataemic rickets secondary to Raine Syndrome treated at Great Ormond Street Hospital for Children, a tertiary referral hospital.

Case Report: Squamous Suture Synostosis in Raine Syndrome Case Report and Literature Review

“…The prevalence of RS is one in a million individuals with Arab ancestry, accounting for most cases. 7,8 According to previous cases, RS is fatal within the first few weeks of life because of pulmonary hypoplasia and choanal atresia/stenosis. However, several cases have been found in which the patient survived into adolescence or adulthood, implying a non-lethal type of RS, and highlighting that lethality is not essential for diagnosis.…”

“…However, several cases have been found in which the patient survived into adolescence or adulthood, implying a non-lethal type of RS, and highlighting that lethality is not essential for diagnosis. 5,6,8 Moreover, there is no explicit distinction between the lethal and non-lethal forms of RS in terms of genetic and phenotypical expression. 12 The most common findings in newborns with RS are depressed nasal bridge, micrognathia, underdeveloped midface hypoplasia, wide fontanelles, microcephaly, tented upper lip, low-set ears, prominent exophthalmos, choanal atresia, hyperplastic gum, cleft soft palate.…”

“…For instance, if both parents have an autosomal recessive condition, there are high chances, almost 100%, that the mutated genes will be passed to the children. 8 However, if one mutant gene is inherited, the child is likely to be a carrier but will not show any symptoms of RS. On the other hand, children born from both parents have a 25% chance of being homozygous RS dominant, 50% of being a carrier, and 25% of being affected with RS.…”

Approach to Hypophosphatemic Rickets

“…FAM20C variants cause Raine syndrome, along with hypophosphatemia ( 44 , 45 ), cerebral calcifications, osteosclerosis of long bones, facial and acral dysmorphism, and dental decay. FAM20C enhances DMP1 expression ( 46 ) and phosphorylates FGF23, causing impairment of GALNT3-mediated O-glycosylation and making FGF23 prone to cleavage ( 20 ).…”

Timing of clinical eruption of permanent teeth in children with molar incisor hypomineralization

“…It is thought to be caused by ameloblasts that have been affected by local and systemic factors during the formation of enamel [1]. Studies have reported on eruption disorders in patients with developmental enamel defects other than MIH [2,3]. The eruption is a dynamic process that begins at the initial positioning of the tooth in the alveolar bone and continues until the final positioning at which it is occluded by a dental antagonist.…”