3M syndrome is a rare autosomal recessive genetic disorder characterized by severe growth retardation, dysmorphic facial features, skeletal dysplasia, and normal intelligence. Variants in CUL7, OBSL1, and CCDC8 genes have been reported to be responsible for this syndrome. In this study, the clinical and molecular findings of four 3M syndrome cases from three families are presented. All cases had growth retardation, relative macrocephaly, and typical dysmorphic facial features. Their neurological developments were normal. Sequencing of CUL7, OBSL1, and CCDC8 genes revealed two different novel homozygous variants in CUL7 in Families 1 and 3 and a previously reported homozygous pathogenic variant in OBSL1 in Family 2. In conclusion, a comprehensive dysmorphological evaluation should be obtained in individuals presenting with short stature and in such individuals with typical facial and skeletal findings, 3M syndrome should be considered. Our report expands the genotype of 3M syndrome and emphasizes the importance of thorough physical and dysmorphological examination.

中文翻译：

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症状性矮小的罕见原因：三个家庭的3M综合征

3M综合征是一种罕见的常染色体隐性遗传疾病，其特征是严重的发育迟缓，面部畸形，骨骼发育异常和智力正常。据报道，CUL7，OBSL1和CCDC8基因的变异是造成这种综合征的原因。在这项研究中，提出了来自三个家庭的四例3M综合征病例的临床和分子发现。所有病例均具有发育迟缓，相对大头畸形和典型的畸形面部特征。他们的神经系统发育正常。的测序CUL7，OBSL1和CCDC8基因揭示了两个不同的纯合新颖变体CUL7在家庭1和3中，以及先前报道的在家庭2中在OBSL1中有纯合的致病变异。总之，应该对身材矮小的个体以及具有典型面部和骨骼特征的个体进行全面的畸形评估，应考虑3M综合征。我们的报告扩展了3M综合征的基因型，并强调了全面体检和畸形检查的重要性。