Department of Morphology and Genetics, Universidade Federal de São Paulo, São Paulo, Brazil.
Department of Psychobiology, Universidade Federal de São Paulo, São Paulo, Brazil.
Mol Genet Genomic Med. 2019 Dec;7(12):e997. doi: 10.1002/mgg3.997. Epub 2019 Oct 1.
Malan syndrome is a recently introduced overgrowth disorder described in a limited number of individuals. Haploinsufficiency and also point mutations of NFIX gene have been proposed as its leading causative mechanism, however, due to the limited number of cases and different deletion sizes, genotype/phenotype correlations are still limited.
Here, we report the first Brazilian case of Malan syndrome caused by a 990 kb deletion in 19p13.2p13.12, focusing on clinical and behavioral aspects of the syndrome.
The patient presented with macrocephaly, facial dysmorphisms, hypotonia, developmental delay, moderate thoracolumbar scoliosis, and seizures. The intellectual and behavioral assessments showed severe cognitive, language, and adaptive functions impairments. The 19p deleted region of our patient encompasses NFIX, CACNA1A, which seems to be related to a higher frequency of seizures among individuals with microdeletions in 19p13.2, and 15 other coding genes, including CC2D1A and NACC1, both known to be involved in neurobiological process and pathways.
Deletions involving NFIX gene should be considered in patients with overgrowth during childhood, macrocephaly, developmental delay, and seizures, as well as severe intellectual disability.
Malan 综合征是一种新引入的过度生长障碍,在少数个体中被描述。NFIX 基因的杂合不足和点突变被提出作为其主要的致病机制,然而,由于病例数量有限且缺失大小不同,基因型/表型相关性仍然有限。
在这里,我们报告了首例巴西 Malan 综合征病例,由 19p13.2p13.12 中的 990kb 缺失引起,重点关注该综合征的临床和行为方面。
患者表现为大头畸形、面部畸形、低张力、发育迟缓、中胸腰椎侧凸和癫痫发作。智力和行为评估显示严重的认知、语言和适应功能障碍。我们患者的 19p 缺失区域包括 NFIX 和 CACNA1A,这似乎与 19p13.2 微缺失患者中癫痫发作的更高频率有关,还包括 15 个其他编码基因,包括 CC2D1A 和 NACC1,这两个基因都已知与神经生物学过程和途径有关。
在儿童期过度生长、大头畸形、发育迟缓、癫痫发作以及严重智力残疾的患者中,应考虑涉及 NFIX 基因的缺失。