Genotype-phenotype associations in Sotos syndrome: an analysis of 266 individuals with NSD1 aberrations.
We identified 266 individuals with intragenic NSD1 mutations or 5q35 microdeletions encompassing NSD1 (referred to as "NSD1-positive individuals"), through analyses of 530 subjects with diverse phenotypes. Truncating NSD1 mutations occurred throughout the gene, but pathogenic missense mutations occurred only in functional domains (P < 2 x 10(-16)). Sotos syndrome was clinically diagnosed in 99% of NSD1-positive individuals, independent of the molecular analyses, indicating that NSD1 aberrations are essentially specific to this condition. Furthermore, our data suggest that 93% of patients who have been clinically diagnosed with Sotos syndrome have identifiable NSD1 abnormalities, of which 83% are intragenic mutations and 10% are 5q35 microdeletions. We reviewed the clinical phenotypes of 239 NSD1-positive individuals. Facial dysmorphism, learning disability, and childhood overgrowth were present in 90% of the individuals. However, both the height and head circumference of 10% of the individuals were within the normal range, indicating that overgrowth is not obligatory for the diagnosis of Sotos syndrome. A broad spectrum of associated clinical features was also present, the occurrence of which was largely independent of genotype, since individuals with identical mutations had different phenotypes. We compared the phenotypes of patients with intragenic NSD1 mutations with those of patients with 5q35 microdeletions. Patients with microdeletions had less-prominent overgrowth (P = .0003) and more-severe learning disability (P = 3 x 10(-9)) than patients with mutations. However, all features present in patients with microdeletions were also observed in patients with mutations, and there was no correlation between deletion size and the clinical phenotype, suggesting that the deletion of additional genes in patients with 5q35 microdeletions has little specific effect on phenotype. We identified only 13 familial cases. The reasons for the low vertical transmission rate are unclear, although familial cases were more likely than nonfamilial cases (P = .005) to carry missense mutations, suggesting that the underlying NSD1 mutational mechanism in Sotos syndrome may influence reproductive fitness.
Tatton-Brown
Katrina
K
Section of Cancer Genetics, Institute of Cancer Research, Sutton, Surrey, United Kingdom.
Douglas
Jenny
J
Coleman
Kim
K
Baujat
Genevieve
G
Cole
Trevor R P
TR
Das
Soma
S
Horn
Denise
D
Hughes
Helen E
HE
Temple
I Karen
IK
Faravelli
Francesca
F
Waggoner
Darrel
D
Turkmen
Seval
S
Cormier-Daire
Valerie
V
Irrthum
Alexandre
A
Rahman
Nazneen
N
D000595:Amino Acid Sequence; D002895:Chromosomes, Human, Pair 5 / Q000235:genetics; D005091:Exons; D019066:Facies; D005260:Female; D016368:Frameshift Mutation; D017353:Gene Deletion; D005838:Genotype; D006130:Growth Disorders / Q000235:genetics* / Q000473:pathology; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; D006720:Homozygote; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D007859:Learning Disabilities / Q000235:genetics* / Q000473:pathology; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D020125:Mutation, Missense; D009687:Nuclear Proteins / Q000235:genetics*; D010641:Phenotype; D011110:Polymorphism, Genetic; D011379:Prognosis; D017386:Sequence Homology, Amino Acid; D013577:Syndrome; D016335:Zinc Fingers
D047908:Intracellular Signaling Peptides and Proteins; D009687:Nuclear Proteins; D000076983:Histone Methyltransferases; D011495:Histone-Lysine N-Methyltransferase; C113272:NSD1 protein, human