Pachajoa Harry, Ruiz-Botero Felipe, Isaza Carolina
Faculty of Health, Universidad Icesi, Research Centre on Congenital Anomalies and Rare Diseases (CIACER), Calle 18 No, 122-135, bloque L, Oficina: 5025A Pance, Cali, Colombia.
J Med Case Rep. 2014 Jun 13;8:191. doi: 10.1186/1752-1947-8-191.
Microcephalic osteodysplastic primordial dwarfism is a syndrome characterized by the presence of intrauterine growth restriction, post-natal growth deficiency and microcephaly. Microcephalic osteodysplastic primordial dwarfism type II is the most distinctive syndrome in this group of entities. Individuals affected by this disease present at an adult height of less than 100 cm, a post-pubertal head circumference of 40 cm or less, mild mental retardation, an outgoing personality and bone dysplasia.
We report the first case of a five-year-old Colombian boy of mixed race ancestry (mestizo), with clinical features of microcephaly, prominent and narrow nose, arched palate, amelogenesis imperfecta, short stature, tall and narrow pelvis, disproportionate shortening of fore-arms and legs, and mild coxa vara. Analysis of the PCNT gene by sequencing showed the presence of a nucleotide change in exon 10, c. 1468C>T, evidencing a new mutation not reported in the literature for microcephalic osteodysplastic primordial dwarfism.
The new mutation identified in this case could be associated with the severity of the phenotypic expression of the disease, resulting in the extreme short stature of the patient. Further studies are required to reach an explanation that can justify such findings, and it is vital to emphasize the importance of detection and follow-up by the epidemiological surveillance groups in birth defects and rare diseases.
小头畸形性骨发育不良原发性侏儒症是一种以宫内生长受限、出生后生长发育迟缓及小头畸形为特征的综合征。II型小头畸形性骨发育不良原发性侏儒症是该组病症中最具特色的综合征。患有这种疾病的个体成年身高不足100厘米,青春期后头围40厘米或更小,有轻度智力障碍、外向性格及骨骼发育异常。
我们报告了首例患有小头畸形、鼻子突出且狭窄、腭裂、牙釉质发育不全、身材矮小、骨盆高且窄、前臂和腿部不成比例缩短以及轻度髋内翻等临床特征的5岁哥伦比亚混血(梅斯蒂索人)男孩。通过测序对PCNT基因进行分析显示,第10外显子存在核苷酸变化,即c.1468C>T,证实这是小头畸形性骨发育不良原发性侏儒症文献中未报道的一种新突变。
该病例中鉴定出的新突变可能与疾病表型表达的严重程度相关,导致患者极度矮小。需要进一步研究以得出能够解释此类发现的结论,并且必须强调出生缺陷和罕见病流行病学监测组进行检测和随访的重要性。