Identification and Characterization of BTD Gene Mutations in Jordanian Children with Biotinidase Deficiency.

Biotinidase deficiency is an autosomal recessive metabolic disorder whose diagnosis currently depends on clinical symptoms and a biotinidase enzyme assay. This study aimed to investigate the mutational status and enzymatic activity of biotinidase deficiency in seven unrelated Jordanian families including 10 patients and 17 healthy family members. Amplified DNA was analyzed by the automated Sanger sequencing method, and the enzymatic assay was performed using a colorimetric assessment. Biotinidase level was significantly lower (p < 0.001) in BTD children compare to their non-affected family members. Genetic sequencing revealed six different mutations in Jordanian patients. One mutation was novel and located in exon 4, which could be a prevalent mutation for biotinidase deficiency in the Jordanian population. Identification of these common mutations and combing the enzymatic activity with genotypic data will help clinicians with regard to better genetic counseling and management through implementing prevention programs in the future.

Two novel mutations of FBN1 in Jordanian patients with Marfan syndrome.

Marfan syndrome is an autosomal dominant inheritance disorder with a 1/5000-live-birth prevalence. More than 3000 mutations have been characterized thus far in the FBN1 gene. The goal of this study is to facilitate Marfan syndrome diagnosis in Jordanian patients using a molecular genetic testing. All of the 65 coding exons and flanking intronic sequences of the FBN1 gene were amplified using polymerase chain reaction and were subjected to sequencing in five unrelated Jordanian patients suspected of having Marfan syndrome. Four different mutations were identified, including two novel mutations: the c.1553dupG frame-shift (p.Tyr519Ilefs*14) and the c.6650G>A (p.Cys2217Tyr) missense mutations. Two other missense mutations, c.2243G>A (p.Cys748Tyr) and c.2432G>A (p.Cys811Tyr), have been previously detected. Patient number five was heterozygous for the synonymous substitution variant c.1875T>C (p.Asn625Asn; rs#25458). Additionally, eight variants in the intronic sequence of the FBN1 gene were identified, of which the c.2168-46A>G mutation was a new variant. The data provide molecular-based evidence linking Marfan syndrome to pathogenic mutations in the FBN1 gene among Jordanians for the first time. Thus, our results will contribute to the better management of the disease using molecular tools and will help in genetic counseling of the patients' families.