TY  - JOUR
A1  - Bahena, Paulina
A1  - Daftarian, Narsis
A1  - Maroofian, Reza
A1  - Linares, Paola
A1  - Villalobos, Daniel
A1  - Mirrahimi, Mehraban
A1  - Rad, Aboulfazl
A1  - Doll, Julia
A1  - Hofrichter, Michaela A. H.
A1  - Koparir, Asuman
A1  - Röder, Tabea
A1  - Han, Seungbin
A1  - Sabbaghi, Hamideh
A1  - Ahmadieh, Hamid
A1  - Behboudi, Hassan
A1  - Villanueva-Mendoza, Cristina
A1  - Cortés-Gonzalez, Vianney
A1  - Zamora-Ortiz, Rocio
A1  - Kohl, Susanne
A1  - Kuehlewein, Laura
A1  - Darvish, Hossein
A1  - Alehabib, Elham
A1  - La Arenas-Sordo, Maria de Luz
A1  - Suri, Fatemeh
A1  - Vona, Barbara
A1  - Haaf, Thomas
T1  - Unraveling the genetic complexities of combined retinal dystrophy and hearing impairment
JF  - Human Genetics
N2  - Usher syndrome, the most prevalent cause of combined hereditary vision and hearing impairment, is clinically and genetically heterogeneous. Moreover, several conditions with phenotypes overlapping Usher syndrome have been described. This makes the molecular diagnosis of hereditary deaf-blindness challenging. Here, we performed exome sequencing and analysis on 7 Mexican and 52 Iranian probands with combined retinal degeneration and hearing impairment (without intellectual disability). Clinical assessment involved ophthalmological examination and hearing loss questionnaire. Usher syndrome, most frequently due to biallelic variants in MYO7A (USH1B in 16 probands), USH2A (17 probands), and ADGRV1 (USH2C in 7 probands), was diagnosed in 44 of 59 (75%) unrelated probands. Almost half of the identified variants were novel. Nine of 59 (15%) probands displayed other genetic entities with dual sensory impairment, including Alström syndrome (3 patients), cone-rod dystrophy and hearing loss 1 (2 probands), and Heimler syndrome (1 patient). Unexpected findings included one proband each with Scheie syndrome, coenzyme Q10 deficiency, and pseudoxanthoma elasticum. In four probands, including three Usher cases, dual sensory impairment was either modified/aggravated or caused by variants in distinct genes associated with retinal degeneration and/or hearing loss. The overall diagnostic yield of whole exome analysis in our deaf-blind cohort was 92%. Two (3%) probands were partially solved and only 3 (5%) remained without any molecular diagnosis. In many cases, the molecular diagnosis is important to guide genetic counseling, to support prognostic outcomes and decisions with currently available and evolving treatment modalities.
KW  - Usher syndrome
KW  - hearing impairment
KW  - combined retinal dystrophy
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-267750
SN  - 1432-1203
VL  - 141
IS  - 3-4
ER  - 
TY  - JOUR
A1  - Hofrichter, Michaela A. H.
A1  - Mojarad, Majid
A1  - Doll, Julia
A1  - Grimm, Clemens
A1  - Eslahi, Atiye
A1  - Hosseini, Neda Sadat
A1  - Rajati, Mohsen
A1  - Müller, Tobias
A1  - Dittrich, Marcus
A1  - Maroofian, Reza
A1  - Haaf, Thomas
A1  - Vona, Barbara
T1  - The conserved p.Arg108 residue in S1PR2 (DFNB68) is fundamental for proper hearing: evidence from a consanguineous Iranian family
JF  - BMC Medical Genetics
N2  - Background:
Genetic heterogeneity and consanguineous marriages make recessive inherited hearing loss in Iran the second most common genetic disorder. Only two reported pathogenic variants (c.323G>C, p.Arg108Pro and c.419A>G, p.Tyr140Cys) in the S1PR2 gene have previously been linked to autosomal recessive hearing loss (DFNB68) in two Pakistani families. We describe a segregating novel homozygous c.323G>A, p.Arg108Gln pathogenic variant in S1PR2 that was identified in four affected individuals from a consanguineous five generation Iranian family.

Methods:
Whole exome sequencing and bioinformatics analysis of 116 hearing loss-associated genes was performed in an affected individual from a five generation Iranian family. Segregation analysis and 3D protein modeling of the p.Arg108 exchange was performed.

Results:
The two Pakistani families previously identified with S1PR2 pathogenic variants presented profound hearing loss that is also observed in the affected Iranian individuals described in the current study. Interestingly, we confirmed mixed hearing loss in one affected individual. 3D protein modeling suggests that the p.Arg108 position plays a key role in ligand receptor interaction, which is disturbed by the p.Arg108Gln change.

Conclusion:
In summary, we report the third overall mutation in S1PR2 and the first report outside the Pakistani population. Furthermore, we describe a novel variant that causes an amino acid exchange (p.Arg108Gln) in the same amino acid residue as one of the previously reported Pakistani families (p.Arg108Pro). This finding emphasizes the importance of the p.Arg108 amino acid in normal hearing and confirms and consolidates the role of S1PR2 in autosomal recessive hearing loss.
KW  - 3D modeling
KW  - autosomal recessive non-synstromic hearing loss
KW  - DFNB68
KW  - mixed hearing loss
KW  - whole exome sequencing
KW  - S1PR2
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-175755
VL  - 19
IS  - 81
ER  -