Craniofacial growth was investigated in boys treated with low-dose testosterone for delayed puberty (> 14 years old; testicular volume < 4 ml; n = 7) and compared with controls (12-14 years; n = 37). Cephalometric radiographs, statural height and pubertal stage were recorded at the start of the study and after 1 year. Craniofacial growth was assessed by nine linear measurements. At the beginning of the study, statural height, mandibular ramus length, upper anterior face height, and total cranial base length were significantly shorter in the delayed puberty boys than in the controls. After 1 year, the growth rate of the statural height, total mandibular length, ramus length, and upper and total anterior face height was significantly higher in the treated boys than in the untreated height-matched controls (n = 7). The craniofacial measurements were similar in the treated boys as compared with the controls. These results show that statural height and craniofacial dimensions are low in boys with delayed puberty. Low doses of testosterone accelerate statural and craniofacial growth, particularly in the delayed components, thus leading towards a normalization of facial dimensions.
MSX1 mutations have been reported in four unrelated families with autosomal dominant tooth agenesis. In one family, some individuals also had cleft lip and/or palate. We have identified a novel MSX1 mutation (559 C --> T, resulting in Gln187Stop) in three individuals of one family.
Purpose
Here we aimed to identify a novel genetic cause of tooth agenesis (TA) and/or orofacial clefting (OFC) by combining whole exome sequencing (WES) and targeted re-sequencing in a large cohort of TA and OFC patients.
Methods
WES was performed in two unrelated patients, one with severe TA and OFC and another with severe TA only. After identifying deleterious mutations in a gene encoding the low density lipoprotein receptor-related protein 6 (LRP6), all its exons were re-sequenced with molecular inversion probes, in 67 patients with TA, 1,072 patients with OFC and in 706 controls.
Results
We identified a frameshift (c.4594delG, p.Cys1532fs) and a canonical splice site mutation (c.3398-2A>C, p.?) in LRP6 respectively in the patient with TA and OFC, and in the patient with severe TA only. The targeted re-sequencing showed significant enrichment of unique LRP6 variants in TA patients, but not in nonsyndromic OFC. From the 5 variants in patients with TA, 2 affect the canonical splice site and 3 were missense variants; all variants segregated with the dominant phenotype and in 1 case the missense mutation occurred de novo.
Conclusion
Mutations in LRP6 cause tooth agenesis in man.
These data indicate that the periodontium in UCLP patients can cope well with a long-term orthodontic treatment, even in unfavourable conditions (like absence of attached gingiva and poor oral hygiene).
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