Fig. 1: Variant classification, coding consequences, inheritance patterns and variant origins of the molecularly solved fetuses in the cohort.

Each unique variant is counted once per patient if present in a homozygous state. A Classification and proportions of variants of uncertain significance (VUS), likely pathogenic (LP), and pathogenic (P). A total of 31 variants were detected, eight likely pathogenic, 19 pathogenic variants, and four VUS. B Categorization of the variants based on their type: structural variant (SV), single nucleotide variant (SNV), or insertion/deletion (INDEL). In total, 31 variants were detected; out of these, the majority were SNVs. C Predicted coding consequences of the variants, categorized into missense, nonsense, frameshift, splice site, and other variants. The “other” category includes the prediction of a new start codon in SEC24D, an intragenic deletion in IFT74 and an in-frame indel in COL2A1. D Inheritance patterns and variant origins in the cohort. Inheritance patterns are categorized into autosomal dominant (AD), autosomal recessive (AR), and X-linked dominant (XLD), the majority being AD inheritance (19 out of 27 cases, corresponding to 70%). Among the AD cases, 12 were confirmed as de novo occurrences, and in an additional seven cases, de novo inheritance was assumed as neither of the parents exhibited the phenotype. Each fetus diagnosed with an AR condition, whether homozygous or compound heterozygous variants, is counted once. The variants identified in fetus number 28 have been excluded from the AR category, as this case remains molecularly unsolved. For the AR conditions (n = 7), all parents (n = 14) were tested and confirmed heterozygous carriers of the variants. Three fetuses carried homozygous variants, and four had compound heterozygous status. The XLD condition (fetus 24) was inherited de novo, confirmed by segregation analysis.