Clinical and genetic characteristics of the first Russian patient with a syndrome of craniofacial dysmorphia-deafness-anomalies of the upper limbs, caused by a mutation in the <i>PAX3</i> gene

Craniofacial dysmorphia-deafness-anomalies of the upper limbs is a rare autosomal dominant syndrome caused by variants in the PAX3 gene. In contrast to the two main nosological forms – Waardenburg syndrome types 1 and 3, caused by variants in this gene, the syndrome of craniofacial dysmorphias-deafness-anomalies of the upper limbs is not characterized by the presence of hair hypopigmentation and heterochromia of the iris, while congenital contractures of the wrist and interphalangeal joints of the hands. There is a description in the literature of three patients from the same family with a syndrome caused by the c.141C>G(p.Asn47Lys) variant in the PAX3 gene. Aim of the work is to present the clinical and genetic characteristics of the first Russian patient with the syndrome of craniofacial dysmorphia-deafness-anomalies of the upper extremities. Molecular genetic analysis of a 1-year and 10-month-old proband with phenotypic signs of the syndrome of craniofacial dysmorphia-deafness-anomalies of the upper limbs was carried out by direct automatic Sanger sequencing of the entire coding sequence of the PAX3 gene. Genotyping of parents was carried out by direct automatic sequencing according to Sanger. Sequencing was carried out on an ABIPrism3500хI instrument (Applied Biosystems) in accordance with the manufacturer’s protocol; primer sequences were selected according to the reference sequence of the target regions of the PAX3 gene (NM_181459.4). In Russian proband 1 year 10 months-old, the phenotypic characteristics of the syndrome of craniofacial dysmorphia-deafness-anomalies of the upper limbs did not differ from the description of sick family members presented in the literature. A molecular genetic study revealed a heterozygous variant c.141C>G(p.Asn47Lys) in the PAX3 gene in the presented patient.