ABSTRACT
Background: Sex determining region Y box transcription factor 2 (SOX2) mutations lead to bilateral anophthalmia with autosomal dominant human inheritance. SOX2 mutations could result in severe ocular phenotypes usually associated with variable systemic defects. Most patients described with SOX2 anophthalmia syndrome possessed de novo mutations in this gene. Case Presentation: In this case report, we describe 2 brothers with mental retardation and bilateral anophthalmia caused due to SOX2 germline mosaicism in unaffected parents. Next-generation DNA sequencing was carried out to determine the family's possible cause of genetic mutation. Sanger sequencing was performed on the patients and their parents. Prenatal diagnosis was done in both pregnancies of the older brother's wife via chorionic villus sampling. A novel heterozygous pathogenic frameshift deletion variant (exon1:c.58_80del:p.G20fs) was identified in the SOX2 gene, which was confirmed by Sanger sequencing in both affected brothers and did not exist in healthy parents, indicating germline mosaicism. Conclusion: Most SOX2 mutations known look to arise de novo in probands and are diagnosed through anophthalmia or microphthalmia. Prenatal diagnosis should be offered to healthy parents with a child with SOX2 mutation every pregnancy.
ABSTRACT
Deletion 9p syndrome is a rare chromosomal abnormality with a wide spectrum of manifestations such as craniofacial dysmorphism, congenital anomalies, and psychomotor delay. We report a case of a seven-year-old girl with simultaneous 9p24.3 deletion and 8p23.3 duplication detected using multiplex ligation-dependent probe amplification (MLPA). Chromosomal and cytogenetic analyses using MLPA are effective in assessing genetic abnormalities in patients with developmental delay and mental retardation. We found breakpoints at 9p24.3 and duplication in the 8p23.3 region, leading to a wide variety of manifestations including speech delay, upslanting palpebral fissures, hypertelorism, epicanthal fold, high arched eyebrows, flat nasal bridge, thin upper lip, and cleft palate. Simultaneous detection of 9p24.3 deletion and 8p23.3 duplication has been rarely reported. Clinical phenotypes of our patient resembled the features of Nicolaides-Baraitser syndrome, which might have been primarily caused by the haploinsufficiency of SMARCA2 (SWI/SNF-related, matrix associated, actin-dependent regulator of chromatin, subfamily A, member 2) gene located at 9p24.3.
Subject(s)
Craniofacial Abnormalities , Intellectual Disability , Actins/genetics , Chromatin , Humans , Intellectual Disability/genetics , Multiplex Polymerase Chain ReactionABSTRACT
beta-Thalassemias are a group of heterogenous recessive disorders common in many parts of the world. Despite the great advances in the treatment of thalassemia, there is so far no cure, but perhaps bone marrow transplantation (BMT) is a possibility. Prevention, using prenatal diagnosis and selective abortion in the cases where the fetus is found to be affected, should be considered as a sensible alternative. During the past 5 years, 112 couples have been referred to our Center for detection of their beta-thalassemia (beta-thal) carrier status. In this group, common and rare mutations were detected. Of these, 106 couples (94.6%) came for counseling during pregnancy and six (5.4%) came before becoming pregnant. Prenatal diagnosis was performed for the 106 couples at risk. Fetal DNA was obtained from both chorionic villus sampling (CVS) (99) and amniotic fluid (7). Using reverse hybridization, 64 (60.4%) were found to be heterozygous for a beta-thal mutation and 24 (22.6%) were normal. Eighteen (17.0%) were found to carry an affected fetus and these pregnancies were terminated.
