Background Oculocutaneous albinism (OCA) is a human autosomal-recessive hypopigmentation disorder with hypopigmentation in the skin, hair, and eyes. OCA1 and OCA2 are caused by mutations of the TYR and OCA2 genes, respectively, which are responsible for most oculocutaneous albinism. However, the incidence of oculocutaneous albinism patients in Guangxi remains unclear. Methods To evaluate the molecular basis of oculocutaneous albinism in thirty-six patients in Guangxi, China. Peripheral venous blood samples were collected from these unrelated patients. The TYR and OCA2 genes of all individuals were analyzed by direct DNA sequencing and the sequences compared with are reference database and bioinformatics analysis. Results Among the 36 OCA patients, 8(22.2%) were found mutations on TYR gene , 28 (77.8%) on OCA2 . And we identified Twenty-seven different TYR and OCA2 mutations in these patients, including one novel TYR framshift mutation c.561_562insTTATTATGTGTCAAATTATCCCCCA, three novel OCA2 mutations: one nonsense mutation c.2195C > G(p.S732X), one deletation mutation(c.1139-1141delTGG), one missense mutations c.2495A > C(p.H832P). The population screening and the bioinformatic analysis to determined the effects of the mutations, which revealed these four novel mutations were pathogenic. Conclusions This study expands the mutation spectrum of oculocutaneous albinism. Four novel mutational alleles c.1139-1141delTGG, c.1832 T > C and c.2195C > G and of the OCA2 gene and c.561_562insTTATTATGTGTCAAATTATCCCCCA of TYR were associated with OCA. The genotype–phenotype correlations suggest that molecular diagnosis is more accurate and important in OCA. Electronic supplementary material The online version of this article (10.1186/s12881-019-0842-7) contains supplementary material, which is available to authorized users.

Osteogenesis imperfecta (OI) is a rare congenital disorder characterized by bone fragility and fractures, and associated with bone deformity, short stature, dentin, ligament and blue-gray eye sclera. OI is caused by a heterozygous mutation in collagen α-1(I) chain (COL1A1) or collagen α-2(I) chain (COL1A2) genes that encode α chains of type I collagen. Collagen α chain peptide contains an N-propeptide, which has a role in assembly and processing of collagen. Point mutations in the N-propeptide domain appear to trigger OI. In the present study, a novel heterozygous missense mutation, c.281T>A (p.Val94Asp), was identified in the von Willebrand C domain of N-terminal of type I collagen in an individual with type IV OI. The majority of N-terminal mutations are associated with OI/Ehlers-Danlos syndrome (EDS); however, in the present study, the affected individual did not suffer from EDS and the level of serum phosphorus of the patient was low (0.67 mmol/l). A number of clinical phenotypes were observed at the same variation site or in the same region on the polypeptide chain of COL1A, which suggests that additional genetic and environmental factors may influence the severity of OI. The present study may provide insight into the phenotype-genotype association in collagen-associated diseases and improve clinical diagnosis of OI.