Establishment of a Pilot Newborn Screening Program for Spinal Muscular Atrophy in Saint Petersburg.

Spinal muscular atrophy 5q (SMA) is one of the most common neuromuscular inherited diseases and is the most common genetic cause of infant mortality. SMA is associated with homozygous deletion of exon 7 in the SMN1 gene. Recently developed drugs can improve the motor functions of infants with SMA when they are treated in the pre-symptomatic stage. With aim of providing an early diagnosis, newborn screening (NBS) for SMA using a real-time PCR assay with dried blood spots (DBS) was performed from January 2022 through November 2022 in Saint Petersburg, which is a representative Russian megapolis. Here, 36,140 newborns were screened by the GenomeX real-time PCR-based screening test, and three genotypes were identified: homozygous deletion carriers (4 newborns), heterozygous carriers (772 newborns), and wild-type individuals (35,364 newborns). The disease status of all four newborns that screened positive for the homozygous SMN1 deletion was confirmed by alternate methods. Two of the newborns had two copies of SMN2, and two of the newborns had three copies. We determined the incidence of spinal muscular atrophy in Saint Petersburg to be 1 in 9035 and the SMA carrier frequency to be 1 in 47. In conclusion, providing timely information regarding SMN1, confirmation of disease status, and SMN2 copy number as part of the SMA newborn-screening algorithm can significantly improve clinical follow-up, testing of family members, and treatment of patients with SMA.

Cytogenomic Profile of Uterine Leiomyoma: In Vivo vs. In Vitro Comparison.

We performed a comparative cytogenomic analysis of cultured and uncultured uterine leiomyoma (UL) samples. The experimental approach included karyotyping, aCGH, verification of the detected chromosomal abnormalities by metaphase and interphase FISH, MED12 mutation analysis and telomere measurement by Q-FISH. An abnormal karyotype was detected in 12 out of 32 cultured UL samples. In five karyotypically abnormal ULs, MED12 mutations were found. The chromosomal abnormalities in ULs were present mostly by complex rearrangements, including chromothripsis. In both karyotypically normal and abnormal ULs, telomeres were ~40% shorter than in the corresponding myometrium, being possibly prerequisite to chromosomal rearrangements. The uncultured samples of six karyotypically abnormal ULs were checked for the detected chromosomal abnormalities through interphase FISH with individually designed DNA probe sets. All chromosomal abnormalities detected in cultured ULs were found in corresponding uncultured samples. In all tumors, clonal spectra were present by the karyotypically abnormal cell clone/clones which coexisted with karyotypically normal ones, suggesting that chromosomal abnormalities acted as drivers, rather than triggers, of the neoplastic process. In vitro propagation did not cause any changes in the spectrum of the cell clones, but altered their ratio compared to uncultured sample. The alterations were unique for every UL. Compared to its uncultured counterpart, the frequency of chromosomally abnormal cells in the cultured sample was higher in some ULs and lower in others. To summarize, ULs are characterized by both inter- and intratumor genetic heterogeneity. Regardless of its MED12 status, a tumor may be comprised of clones with and without chromosomal abnormalities. In contrast to the clonal spectrum, which is unique and constant for each UL, the clonal frequency demonstrates up or down shifts under in vitro conditions, most probably determined by the unequal ability of cells with different genetic aberrations to exist outside the body.

Catechol-O-methyltransferase Val158Met polymorphism is associated with increased risk of multiple uterine leiomyomas either positive or negative for MED12 exon 2 mutations.

AIMS: To study the possible association of catechol-O-methyltransferase (COMT) Val158Met polymorphism with multiple and solitary uterine leiomyomas (ULs) and to check whether the COMT Val/Val genotype is associated with MED12 exon 2 mutations in fibroids. METHODS: The COMT Val158Met allele and genotype frequencies were compared between age-matched women with ULs (n=104) and controls (n=59). Patients with UL were subcategorised by diagnosis of solitary (n=59) or multiple (n=45) fibroids and by the presence of somatic MED12 exon 2 mutations in at least one fibroid (n=32) or in neither fibroid (n=26). The association of COMT Val/Val genotype with the presence of any ULs, solitary/multiple ULs and ULs positive/negative for MED12 exon 2 mutations was evaluated by χ2 tests using a dominant genotype model (G/G vs G/A+A/A) and expressed as ORs and 95% CIs. RESULTS: The COMT Val/Val genotype frequency did not differ between the patients with UL and the controls (28.8% vs 18.6%, p=0.149, OR 1.77; CI 0.81 to 3.86). However, it was significantly higher in the patients who had multiple UL compared with the solitary UL (40% vs 20.3%, p=0.028, OR 2.61; CI 1.09 to 6.24) and to the controls (40% vs 18.6%, p=0.016, OR 2.91; CI 1.20 to 7.06). No association of the COMT Val/Val genotype with UL-specific MED12 exon 2 mutations was found (p=0.662, OR 0.77; CI 0.23 to 2.53). CONCLUSIONS: Women with COMT Val/Val genotype are at high risk of developing multiple uterine fibroids either positive or negative for MED12 exon 2 mutations. These data are important to design new strategies for UL prophylaxis and treatment.

Frequency and Spectrum of MED12 Exon 2 Mutations in Multiple Versus Solitary Uterine Leiomyomas From Russian Patients.

Uterine leiomyomas (ULs) are common benign tumors affecting women of different ethnicities. A large proportion of UL has mutations in MED12. Multiple and solitary ULs usually manifest with different severities, suggesting that their origin and growth pattern may be driven by different molecular mechanisms. Here, we compared the frequency and the spectrum of MED12 exon 2 mutations between multiple (n=82) and solitary (n=40) ULs from Russian patients. Overall, we detected MED12 exon 2 mutations in 51.6% (63/122) of ULs. The frequency of MED12 exon 2 mutations was almost two-fold higher in samples from the multiple UL patients than in those from the solitary UL patients - 61% (50/82) versus 32.5% (13/40). The increased MED12 exon 2 mutation frequency in the multiple ULs was not accompanied by significant alterations in the spectrum of mutation categories, which included missense mutations, deletions, splicing defects, and multiple (double/triple) mutations. Each mutation category had a unique mutation set, comprising both frequent and rarely encountered mutations, which did and did not overlap between the studied groups, respectively. We conclude that in contrast to the solitary ULs, the multiple ULs predominantly originate through MED12-associated mechanisms. The nature of these mechanisms seems to be similar in solitary and multiple ULs, as they contain similar mutations. In multiple UL patients, they are likely to be nonsporadic, indicating the existence of specific factors predisposing to multiple UL development. These data suggest that to clearly understand UL pathogenesis, solitary and multiple tumors should probably be analyzed as separate sets.