目的:报告1例女孩表现为以突出的溶骨性病变和外胚层缺损为特征的A型下颌骨发育不良(MADA),与罕见的纯合LMNA错义突变相关(c.1579C>T)。
方法:在住院期间对一名6岁女孩进行评估,表现出以下畸形体征:具有突出眼睛的异形相,明显的小颌和后颌,小喙鼻子,牙齿拥挤,嘴唇薄,全身性脂肪营养不良,狭窄和倾斜的肩膀,骨端指骨的广义关节刚度和骨重吸收。在皮肤病学检查中,萎缩性皮肤,皮肤弹性丧失,角化过度,真皮钙质沉着,并观察到色素沉着和低色斑。放射学检查显示双侧下颌髁突缺失,锁骨吸收局部无定形骨量与肩胛骨汇合,肩关节半脱位和严重的骨发育不良,髋关节发育不良,骨量减少和皮下钙化。
结论:MADA是一种由LMNA基因突变引起的罕见常染色体隐性遗传疾病。它的特点是颅面畸形,骨骼异常,皮肤改变,身体某些区域的脂肪营养不良和过早衰老。典型的MADA是由LMNA基因中的p.R527H突变引起的。然而,从患者口腔上皮细胞进行的分子分析显示罕见突变c.1579C>T,p.LMNA外显子9中的R527C。这是文献中描述的具有这种突变的第六个家族。
OBJECTIVE: To report the case of a girl presenting a severe phenotype of mandibuloacral dysplasia type A (MADA) characterized by prominent osteolytic changes and ectodermal defects, associated with a rare homozygous LMNA missense mutation (c.1579C>T).
METHODS: A 6-year-old girl was evaluated during hospitalization exhibiting the following dysmorphic signs: subtotal alopecia, dysmorphic facies with prominent eyes, marked micrognathia and retrognathia, small beaked nose, teeth crowding and thin lips, generalized lipodystrophy, narrow and sloping shoulders, generalized joint stiffness and bone reabsorption in the terminal phalanges. In dermatological examination, atrophic skin, loss of cutaneous elasticity, hyperkeratosis, dermal calcinosis, and hyperpigmented and hypochromic patches were observed. Radiology exams performed showed bilateral absence of the mandibular condyles, clavicle resorption with local amorphous bone mass confluence with the scapulae, shoulder joints with subluxation and severe bone dysplasia, hip dysplasia, osteopenia and subcutaneous calcifications.
CONCLUSIONS: MADA is a rare autosomal recessive disease caused by mutations in LMNA gene. It is characterized by craniofacial deformities, skeletal anomalies, skin alterations, lipodystrophy in certain regions of the body and premature ageing. Typical MADA is caused by the p.R527H mutation in the LMNA gene. However, molecular analysis performed from oral epithelial cells obtained from the patient showed the rare mutation c.1579C>T, p. R527C in the exon 9 of LMNA. This is the sixth family identified with this mutation described in the literature.