Genetic influence and heritability in mandibular prognathism of Korean families

INTRODUCTION: This study examined the genetic influence of mandibular prognathism epidemiologically in Korean families. MATERIALS AND METHODS: Over a 5-year period from 2005 to 2009, a questionnaire with a pedigree chart was given to 100 (male 51, female 49) probands with skeletal Class III mandibular prognathism, who had undergone orthognathic surgery in Samsung Medical Center. RESULTS: The average age of the probands was 22.1. The average SNA, SNB and ANB angles of the probands were 81.2degrees, 84.1degreesand -2.9degrees, respectively. A total of 2729 (male 1,354, female 1,375) family members were examined, and the affected ratio of the families was 3.5% with no significant difference between genders. 45% of families had at least one member with a Class III malocclusion other than the proband. The affected ratio of the first-degree relatives (10.9%) was significantly higher than those of the second-degree (3.3%) and third-degree (1.9%) relatives. The affected ratio of the total relatives from the male probands (4.2%) was significantly higher than that of the female probands (2.8%). Heritability (h2, Falconer'method) was estimated to be 29.8% (0.298+/-0.059) in first-degree relatives. CONCLUSION: These results showed the significant influence of mandibular prognathism with relatively low heritability in first-degree relatives in Korean families of probands, who had undergone orthognathic surgery to correct a skeletal Class III malocclusion.

Concurrent Severe Alopecia Areata in Dizygotic Twins / 대한피부과학회지

A recent genetic study of alopecia areata shows that the patients with early onset, severe, familial group could be separated from the patients with later onset, milder severity with good prognosis in their genetic background. We have experienced an intractable clinical course of alopecia areata in dizygotic twin brothers and have come to sympathise with the genetic influence of the disease. The alopecia areata of the two brothers began for both at about 10 years of age and became severe and persistent over the twenties up to the present times. All treatments failed. The patients were thought to be an example showing the importance of genetic influences in the treatment of alopecia areata.