Investigation of the relationship between reproductive disorders and chromosomal abnormalities in a large-scale, single-center 10-year retrospective study.

OBJECTIVE: Chromosomal changes are an important cause of reproductive disorders. This study investigated the chromosomal changes and prevalence of pathologies in individuals admitted to our Genetic Evaluation Center over a 10-year period due to a reproductive disorder. MATERIALS & METHODS: The chromosomal findings of 4345 individuals with reproductive disorders who applied to our Genetic Evaluation Center at Akdeniz University in Antalya, Turkey between 2011 and 2021 were retrospectively evaluated. RESULTS: In this study, an abnormal karyotype was found in a total of 138 individuals (87 males and 51 females). Although the incidence of this abnormal karyotype varied among the diseases in the reproductive disorder subgroups, it was most frequently seen in azoospermia (17.0%). Of the 138 abnormalities, 75 were numerical and 54 were structural. The remaining 9 abnormalities consisted of 6 sex reversals and 3 patients with both numerical and structural anomalies. Additionally, the X chromosome was the chromosome most frequently involved in these abnormalities, being observed in 40.6% of patients. CONCLUSION: This 10-year, single-center study involved one of the largest case series in the literature to investigate the subtypes of reproductive disorders and their chromosomal relationship. Although the importance of chromosome analysis has been deemphasized, it is still recommended for use by the guidelines and, as the results of this study demonstrate, is still a highly effective method in the investigation of reproductive disorders. Furthermore, chromosome analysis of individuals diagnosed with a reproductive disorder is also very important in the practice of the increasingly utilized preimplantation genetic diagnosis (PGD).

Evaluation of exonic copy numbers of SMN1 and SMN2 genes in SMA.

SMA is a neuromuscular disease and occurs primarily through autosomal recessive inheritance. Identification of deletions in the SMN1 gene especially in the exon 7 and exon 8 regions (hot spot), are used in carrier testing. The exact copy numbers of those exons in the SMN1 and SMN2 genes in 113 patients who presented with a pre-diagnosis of SMA were determined using MLPA method. We aimed to reveal both the most common copy number profiles of different SMA types. It was found that the frequency of homozygous deletions in SMN1 was 15.9%, while heterozygous deletions was 16.9%. The most common SMN-MLPA profile was 0-0-3-3. In the cases with homozygous deletion, SMA type III diagnosis was observed most frequently (44%), and the rate of consanguineous marriage was found 33%. Two cases with the same exonic copy number profile but with different clinical subtypes were identified in a family. We also detected distinct exonic deletion and duplication MLPA profiles for the first time. We created "the SMA signature" that can be added to patient reports. Furthermore, our data are important for revealing potential local profiles of SMA and describing the disease in genetic reports in a way that is clear and comprehensive.

Coexistence of a Homozygous Chromosome 4q35.2 Deletion and Hidden IQSEC2 Pathogenic Variant in a Child with Intellectual Disability.

Terminal deletions in the long arm of chromosome 4 are an uncommon event, with a worldwide incidence of approximately 0.001%. The majority of these deletions occur de novo. Terminal deletion cases are usually accompanied by clinical findings that include facial and cardiac anomalies, as well as intellectual disability. In this study, we describe the case of a 2-year-old girl, the fourth child born to consanguineous parents. While her karyotype was normal, a homozygous deletion was identified in the chromosome 4q35.2 region by subtelomeric FISH. A heterozygous deletion of the chromosome 4q35.2 region was observed in both parents. According to the literature, this is the first report of a case that has inherited a homozygous deletion of chromosome 4qter from carrier parents. Subsequent array-CGH analyses were performed on both the case and her parents. Whole-exome sequencing was also carried out to determine potential variants. We detected a NM_001111125.3:c.2329G>T (p.Glu777Ter) nonsense variant of the IQSEC2 gene in the girl, a variant that is related to X-linked intellectual disability.

Gap-PCR Screening for Common Large Deletional Mutations of ß-Globin Gene Cluster Revealed a Higher Prevalence of the Turkish Inversion/Deletion (δß)0 Mutation in Antalya.

OBJECTIVE: Although the calculated carrier frequency for point mutations of the ß-globin gene is around 10% for Antalya Province, nothing is known about the profile of large deletional mutations involving the ß-globin gene. In this study, we aimed to screen common deletional mutations in the ß-globin gene cluster in patients for whom direct DNA sequencing was not able to demonstrate the mutation(s) responsible for the disease phenotype. MATERIALS AND METHODS: Thirty-one index cases selected with a series of selection events among 60 cases without detected ß-globin gene mutation from 580 thalassemia-related cases tested by direct sequencing over the last 4 years in our diagnostic center were screened for the most common 8 different large deletional mutations of the ß-globin gene cluster by gap-PCR. RESULTS: We detected 1 homozygous and 9 heterozygous novel unrelated cases for the Turkish inversion/deletion (δß)0 mutation in our series of 31 cases. Our study showed that the Turkish inversion/deletion (δß)0 mutation per se accounts for 16.6% of the unidentified causative alleles and also accounts for 1.5% of all detected mutations over the last 4 years in our laboratory. CONCLUSION: Since molecular diagnosis of deletional mutations in the ß-globin gene cluster warrants different approaches, it deserves special attention in order to provide prenatal diagnosis and prevention opportunities to the families involved. We conclude that the Turkish inversion/deletion (δß)0, as the most prevalent deletional mutation detected so far, has to be routinely tested for in Antalya, and the gap-PCR approach has valuable diagnostic potential in the patients at risk.

Bilateral congenital cataracts in an infant with Klinefelter syndrome.

Congenital cataract is one of the most treatable causes of visual impairment and blindness during infancy, with an estimated prevalence of approximately 2.5:10,000 infants under the age of 1 year. Congenital cataract can be observed with certain chromosomal abnormalities, such as trisomies, deletions, translocations and Turner syndrome. In Klinefelter syndrome, however, ocular complications and cataract are not commonly encountered, so reports in the literature are very rare. In this manuscript, we present a 3-month-old male infant who had congenital cataracts. Chromosomal analysis revealed that his karyotype was 47,XXY. He did not show any of the main clinical signs of Klinefelter syndrome because of his very young age. To the best of our knowledge, our patient is only the second-ever case reported in the literature in which congenital cataracts have been found in an infant with a nonmosaic 47,XXY karyotype. The aim of the present report is to both describe the ocular abnormalities that can sometimes be found in Klinefelter syndrome and to emphasize the importance of performing a karyotype analysis in order to rule out chromosome abnormalities in patients with congenital cataracts.

Mixed gonadal dysgenesis in a patient with de novo tas(Y;19)(p11.3;q13.4) and 45,X mosaicism.

We report a patient with a de novo telomeric association between chromosomes 19 and Y in conjunction with mixed gonadal dysgenesis. The patient was first admitted to the clinic because of abnormal external genitalia. Laparoscopic evaluation revealed (1) a rudimentary uterus, one fallopian tube, and a small gonad resembling an ovary on the right side, and (2) an immature fallopian tube, a vas deferens, and a gonad resembling a testis on the left side. Conventional cytogenetic analysis performed on cultivated peripheral blood cells, and tissue obtained from the phallus and a gonadal structure which resembled a testis revealed two different cell lines with the 46,X,tas (Y;19)(p11.3;q13.4) and 45,X karyotype. Y chromosome microdeletion analysis showed that the patient did not have any genomic deletions in the AZFa, b, c, or SRY regions on the long arm of the Y chromosome. This is the first report of a patient with mixed gonadal dysgenesis that is accompanied by a telomeric association between chromosomes 19 and Y with 45,X mosaicism.

The association of Klinefelter syndrome and multiple pterygium syndrome: an unusual presentation.

Multiple pterygium syndrome is characterized by a number of phenotypic features, small stature, webbing of the neck, elbows, and/or knees, and joint contractures. In this report, we present an 11-year-old boy who had the classical findings of multiple pterygium syndrome, and his chromosomal analysis revealed a 47,XXY karyotype. Interestingly, he did not show any of the main clinical signs of Klinefelter syndrome. This patient appears to be the first reported case in the literature in which a non-mosaic 47,XXY karyotype has been found in a patient with multiple pterygium syndrome. The aim of the present report is to describe a non-classic Klinefelter syndrome associated with multiple pterygium syndrome and to emphasize the importance of karyotype analysis in patients with multiple pterygium syndrome.