5q spinal muscular atrophy (5q SMA) is one of the most common autosomal recessive disorders in the Russian Federation. The first medication to treat 5q SMA was registered in the Russian Federation for treatment of all 5q SMA types in 2019, and the last of the three currently available in December 2021. We launched the pilot newborn screening (NBS) program for 5q SMA in Moscow, the Russian Federation, starting in 2019. During the pilot program, 23,405 neonates were tested for the deletion of exon 7 of the SMN1 gene, the most common cause of 5q SMA. We used the SALSA® MC002 SMA Newborn Screen Kit (MRC Holland) to specifically detect homozygous deletions of SMN1 exon 7. We used the restriction fragment length polymorphism (RFLP) approach to validate detected homozygous deletions and the SALSA MLPA Probemix P060 SMA Carrier Kit (MRC Holland) to determine the SMN2 exon 7 copy number to prescribe gene therapy for 5q SMA. Three newborns with a homozygous deletion of the SMN1 gene were detected. The calculated birth prevalence of 1:7801 appears to be similar to the results in other European countries. The children did not show any signs of respiratory involvement or bulbar weakness immediately after birth. Until now, no 5q SMA case missed by NBS has been detected.
Introduction: Pathogenic variants in the OFD1 gene are linked to a spectrum of syndromes that exhibit partial clinical overlap. Hemizygous loss-of-function variants are considered lethal in males, while heterozygous loss-of-function variants generally result in oro-facial-digital syndrome type 1. A reported phenotype, Simpson–Golabi–Behmel syndrome type 2, was published once but remains controversial, with many specialists questioning its validity and arguing about its continued listing in the OMIM database. Methods: To investigate the genetic and phenotypic characteristics of the patients, we performed clinical exome sequencing, family-based genetic analysis, X-inactivation studies, electron microscopy, and detailed clinical assessments. Results: Three patients from unrelated families carrying loss-of-function variants in the OFD1 gene were identified, emphasizing the diverse phenotypic spectrum of OFD1-associated disorders. The first patient, a female with a heterozygous frameshift variant p.(Gln398LeufsTer2), was diagnosed with oro-facial-digital syndrome type 1. The second patient, a male with a heterozygous nonsense variant p.(Gln892Ter), presented with features resembling Simpson–Golabi–Behmel syndrome type 2, as previously reported under this diagnosis. The third patient, a male with another heterozygous nonsense variant p.(Glu879Ter), exhibited isolated primary ciliary dyskinesia without any syndromic features. Conclusions: This study contributes to the growing body of evidence on the expanding phenotypic spectrum of OFD1-associated disorders. It underscores the need for further investigation into the molecular mechanisms underlying the diverse presentations and the necessity of re-evaluating diagnostic classifications for conditions such as SGBS2 in the context of variants in the OFD1 gene.
The expanded newborn screening (NBS) program in the Russian Federation was initiated in 2023, among which severe combined immunodeficiency (SCID) is screened using TREC/KREC assays. Here, we report a rare case of a TP63-associated disease identified through this NBS program. Dried blood spots from newborns were initially screened for TREC/KREC levels, and those with values below the cut-off underwent confirmatory testing and further genetic analysis, including whole-exome sequencing (WES). A male newborn was identified with significantly reduced TREC values, indicative of T cell lymphopenia. Genetic analysis revealed a heterozygous NM_003722.5:c.1027C>T variant in TP63, leading to the p.(Arg343Trp) substitution within the DNA binding domain. This mutation has been previously associated with Ectrodactyly–Ectodermal Dysplasia–Cleft lip/palate syndrome (EEC) syndrome and shown to reduce the transactivation activity of TP63 in a dominant-negative manner. This case represents one of the few instances of immune system involvement in a patient with a TP63 mutation, highlighting the need for further investigation into the immunological aspects of TP63-associated disorders. Our findings suggest that comprehensive immunological evaluation should be considered for patients with TP63 mutations to better understand and manage potential immune dysfunctions.