Case report: Disease phenotype associated with simultaneous biallelic mutations in ABCA4 and USH2A due to uniparental disomy of chromosome 1.

Inherited retinal diseases (IRDs) represent a spectrum of clinically and genetically heterogeneous disorders. Our study describes an IRD patient carrying ABCA4 and USH2A pathogenic biallelic mutations as a result of paternal uniparental disomy (UPD) in chromosome 1. The proband is a 9-year-old girl born from non-consanguineous parents. Both parents were asymptomatic and denied family history of ocular disease. Clinical history and ophthalmologic examination of the proband were consistent with Stargardt disease. Whispered voice testing disclosed moderate hearing loss. Next-generation sequencing and Sanger sequencing identified pathogenic variants in ABCA4 (c.4926C>G and c.5044_5058del) and USH2A (c.2276G>T). All variants were present homozygously in DNA from the proband and heterozygously in DNA from the father. No variants were found in maternal DNA. Further analysis of single nucleotide polymorphisms confirmed paternal UPD of chromosome 1. This is the first known patient with confirmed UPD for two recessively mutated IRD genes. Our study expands on the genetic heterogeneity of IRDs and highlights the importance of UPD as a mechanism of autosomal recessive disease in non-consanguineous parents. Moreover, a long-term follow-up is essential for the identification of retinal features that may develop as a result of USH2A-related conditions.

Meibografía infrarroja y evaluación molecular de la mutación del gen p63 en un paciente mexicano con síndrome EEC / Infrared meibography and molecular assessment of p63 gene mutations in a Mexican patient with EEC síndrome

OBJETIVO: Reportar el hallazgo de la meibografía infrarroja en un paciente mexicano con el síndrome de EEC (Ectrodactyly-ectodermal dysplasia-cleft syndrome) confirmado por análisis molecular del gen p63. CASO CLÍNICO: Paciente varón de 31 años de edad que acude por presentar una historia de pérdida visual progresiva en ambos ojos asociada a fotofobia de larga duración. El paciente nació con labio y paladar hendido, y ectodactilia de la mano derecha; posteriormente presentó displasia ungueal, anodoncia y alopecia, con lo que se diagnosticó displasia ectodérmica. Las alteraciones oftalmológicas se limitaron a los anexos y la superficie ocular. La meibografía infrarroja in vivo mostró la ausencia total de glándulas de Meibomio en los párpados inferiores y deficiencia severa en los párpados superiores. Además, identificamos que el paciente es un portador heterocigoto de una mutación de sentido equivocado R304W (C -> T) en el exón 8 del gen p63. DISCUSIÓN: La mutación R304W en la región del gen p63 está definitivamente relacionada con características tales como la ausencia de glándulas de Meibomio

OBJECTIVE: To report the finding of infrared meibography in a Mexican patient with EEC syndrome (Ectrodactyly-ectodermal dysplasia-cleft syndrome) confirmed by molecular analysis of the p63 gene. Clinical case: A 31 year-old male patient was seen due to a history of progressive visual loss in both eyes associated with long-term photophobia. The patient was born with cleft lip and palate, ectrodactyly of right hand, and afterwards, displayed nail dysplasia, anodontia and alopecia, with which ectodermal dysplasia was diagnosed. The ophthalmological findings were limited to the adnexa and the ocular surface. In vivo infrared meibography showed total absence of Meibomian glands in the lower eyelids and severe deficiency in the upper eyelids. In addition, it was shown that the patient was a heterozygous carrier of a missense mutation R304W (C -> T) in exon 8 of the p63 gene. DISCUSSION: The R304W mutation in the p63 gene region is definitely related to characteristics such as the absence of Meibomian glands

Infrared meibography and molecular assessment of p63 gene mutations in a Mexican patient with EEC syndrome. / Meibografía infrarroja y evaluación molecular de la mutación del gen p63 en un paciente mexicano con síndrome EEC.

OBJECTIVE: To report the finding of infrared meibography in a Mexican patient with EEC syndrome (Ectrodactyly-ectodermal dysplasia-cleft syndrome) confirmed by molecular analysis of the p63 gene. CLINICAL CASE: A 31 year-old male patient was seen due to a history of progressive visual loss in both eyes associated with long-term photophobia. The patient was born with cleft lip and palate, ectrodactyly of right hand, and afterwards, displayed nail dysplasia, anodontia and alopecia, with which ectodermal dysplasia was diagnosed. The ophthalmological findings were limited to the adnexa and the ocular surface. In vivo infrared meibography showed total absence of Meibomian glands in the lower eyelids and severe deficiency in the upper eyelids. In addition, it was shown that the patient was a heterozygous carrier of a missense mutation R304W (C → T) in exon 8 of the p63 gene. DISCUSSION: The R304W mutation in the p63 gene region is definitely related to characteristics such as the absence of Meibomian glands.