Femoral-facial syndrome (FFS, OMIM 134780), also known as femoral hypoplasia-unusual face syndrome, is a rare sporadic syndrome associated with maternal diabetes, and comprising femoral hypoplasia/agenesis and a distinct facies characterized by micrognathia, cleft palate, and other minor dysmorphisms. The evaluation of 14 unpublished Brazilian patients, prompted us to make an extensive literature review comparing both sets of data. From 120 previously reported individuals with FFS, 66 were excluded due to: not meeting the inclusion criteria (n = 21); not providing sufficient data to ascertain the diagnosis (n = 29); were better assigned to another diagnosis (n = 3); and, being fetuses of the second trimester (n = 13) due to the obvious difficult to confirm a typical facies. Clinical-radiological and family information from 54 typical patients were collected and compared with the 14 new Brazilian patients. The comparison between the two sets of patients did not show any relevant differences. Femoral involvement was most frequently hypoplasia, observed in 91.2% of patients, and the typical facies was characterized by micrognathia (97%), cleft palate (61.8%), and minor dysmorphisms (frontal bossing 63.6%, short nose 91.7%, long philtrum 94.9%, and thin upper lip 92.3%). Clubfoot (55.9%) was commonly observed. Other observed findings may be part of FFS or may be simply concurrent anomalies since maternal diabetes is a common risk factor. While maternal diabetes was the only common feature observed during pregnancy (50.8%), no evidence for a monogenic basis was found. Moreover, a monozygotic discordant twin pair was described reinforcing the absence of a major genetic factor associated with FFS.

<b><i>Introduction:</i></b> Pathogenic variants in the <i>SLC26A2/DTDST</i> gene cause the following spectrum of phenotypes: achondrogenesis 1B (ACG1B), atelosteogenesis 2 (AO2), diastrophic dysplasia (DTD), and recessive-multiple epiphyseal dysplasia (rMED), the first 2 being lethal. Here, we report a cohort and a comprehensive literature review on a genotype-phenotype correlation of <i>SLC26A2/DTDST</i>-related disorders. <b><i>Methods:</i></b> The local patients were genotyped by Sanger sequencing or next-generation sequencing (NGS). We reviewed data from the literature regarding phenotype, zygosity, and genotype in parallel. <b><i>Results:</i></b> The local cohort enrolled 12 patients, including one with a Desbuquois-like phenotype. All but one showed biallelic mutations, however, only one allele mutated in a fetus presenting ACG1B was identified. The literature review identified 42 articles and the analyses of genotype and zygosity included the 12 local patients. <b><i>Discussion:</i></b> The R279W variant was the most prevalent among the local patients. It was in homozygosity (hmz) in 2 patients with rMED and in compound heterozygosity (chtz) in 9 patients. The genotype and zygosity review of all patients led to the following conclusions: DTD is the most common phenotype in Finland due to a Finnish mutation (c.727–1G&#x3e;C). Outside of Finland, rMED is the most prevalent phenotype, usually associated with R279W in hmz. In contrast, DTD’s genotype is usually in chtz. Despite a large number of variants (38), just 8 are recurrent (R279W, C653S, c.−26+2T&#x3e;C, R178*, K575Sfs*10, V340del, G663R, T512K). The last 3 in hmz lead to lethal phenotypes. The Finnish mutation is found only in chtz outside of Finland, being associated with all 4 classical phenotypes. The p.R178* and p.K575Sfs*10 variants should be viewed as lethal mutations since both were mainly described with lethal phenotypes and were never reported in hmz. The existence of 9 patients with only one mutated allele suggests that other mutations in the other allele of these patients still need to be unveiled.

Molecular diagnosis is important to provide accurate genetic counseling of skeletal dysplasias (SD). Although next-generation sequencing (NGS) techniques are currently the preferred methods for analyzing these conditions, some of the published results have not shown a detection rate as high as it would be expected. The present study aimed to assess the diagnostic yield of targeted NGS combined with Sanger sequencing (SS) for low-coverage exons of genes of interest and exome sequencing (ES) in a series of patients with rare SD and use two patients as an example of our strategy.This study used two different in-house panels. Of 93 variants found in 88/114 (77%) patients, 57 are novel. The pathogenic variants found in the following genes: B3GALT6, PCYT1A, INPPL1, LIFR, of four patients were only detected by SS. In conclusion, the high diagnostic yield reached in the present study can be attributed to both a good selection of patients and the utilization of the SS for the insufficiently covered regions. Additionally, the two case reports-a patient with acrodysostosis related to PRKAR1A and another with ciliopathy associated with KIAA0753, add new and relevant clinical information to the current knowledge.