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We explored the elevational richness patterns of birds in a biodiversity hotspot in south-western China, the Gaoligong Mountains and assessed the role of different spatial factors, climatic factors and landscape composition in shaping the richness patterns. The east slope of the southern part of Gaoligong Mountains (24.79°N-26.49°N, 98.65°E-98.93°E) is the western-most part of the Hengduan Mountains, China. We conducted field surveys of birds at each 300-m band from 700 to 3400 m a.s.l., and for the two bands from 3400 to 4000 m a.s.l., we obtained data from historical records. We obtained climatic recording data from local meteorological stations that were located in our study area and calculated the mean annual temperature and precipitation. We also calculated the area, MDE (the mid-domain effect), NDVI (the normalized difference vegetation index), habitat heterogeneity and human disturbance for each 300-m band. We then used multiple regression analysis to test the explanatory power of different factors for the elevational richness patterns of overall, endemic, non-endemic, large-ranged, and small-ranged birds. A total of 277 breeding bird species were recorded. We found consistent hump-shaped patterns of species richness with elevation with varied peaks for different groups. The richness of endemic birds peaked at higher elevation than non-endemic birds. Temperature and human disturbance played important roles in shaping the richness patterns of most bird groups whereas MDE contributed to the richness pattern of large-ranged species. Although none of the seven factors (area, MDE, mean annual temperature, annual precipitation, NDVI, habitat heterogeneity and human disturbance) showed consistent explanatory power among different species groups, temperature and human disturbance correlated well with most bird groups, indicating that more studies are needed in this biodiversity hotspot to clarify the detailed influence of anthropogenic activities and climate change on elevational distributions of birds.

Purpose To identify the causative mutation with its possible origin in a Chinese family with congenital fibrosis of extraocular muscles type 1 (CFEOM1) and to characterize the ocular phenotypes and lesions in the corresponding intracranial nerves. Methods Three affected siblings and their asymptomatic parents underwent comprehensive ophthalmic examinations and neuropathologic analysis involving magnetic resonance imaging (MRI). KIF21A, PHOX2A, and TUBB3 genes were sequenced on the leukocyte-derived DNA to detect variants. The disease-linked haplotype was analyzed using four microsatellite markers across the KIF21A locus. Results All three affected individuals displayed typical CFEOM1. MRI revealed complicated but consistent neuromuscular abnormalities in the two patients examined, including hypoplastic oculomotor nerves, complete absence of bilateral superior rectus muscles, and unilateral absence of the abducens nerve with marked atrophy of the corresponding lateral rectus muscle. A heterozygous hotspot mutation KIF21A c.2860C>T was identified in all patients, but it was absent in both parents. Haplotype analysis of the disease locus showed the likely maternal inheritance of the disease-associated haplotype to all three affected offspring, strongly suggesting maternal germline mosaicism of the mutation. Conclusions Germline mosaicism of KIF21A c.2860C>T is likely to cause the high occurrence of this mutation in the population. This information may be useful for genetic counseling. KIF21A mutations can affect the abducens nerve and cause complete absence of the bilateral superior rectus muscles. MRI characterization of new CFEOM1 phenotypes would assist clinical management.

Purpose To identify the causative mutations in two Chinese families with autosomal dominant Marfan syndrome and to describe the associated phenotypes. Methods Complete physical, ophthalmic, and cardiovascular examinations were given to the patients and unaffected individuals in the two families. Exclusive linkage mapping was performed for transforming growth factor beta receptor II (TGFBR2) and fibrillin-1 (FBN1) loci in both families. The entire coding region and flanking splice sites of the FBN1 gene were screened for mutations in the two families with Sanger sequencing. The potential mutations of FBN1 were tested in 100 normal controls. Results Lens dislocation was observed in two out of ten patients in the MF1 family and all patients in the MF2 family. However, the MF1 family displayed more severe cardiovascular and skeletal system involvement compared with the MF2 family. The transforming growth factor beta receptor II locus was excluded in both families by linkage analysis. A maximum multipoint lod score score of 2.83 was obtained for marker D15S992 (located in the FBN1 gene) in the MF1 family and 1.51 for the same marker in the MF2 family. Two novel mutations of FBN1, p.C271* and p.C637Y, were identified in the MF1 and MF2 families, respectively. Conclusions Genotype-phenotype correlations in this study indicate that nonsense mutations of FBN1 may correlate with relatively severe systemic phenotypes when compared with cysteine substitutions, the most common type of FBN1 mutations. Genetic diagnosis for patients with Marfan syndrome would help with genetic counseling, clinical intervention, and prognosis.