RESUMO
Proximal region of chromosome 15 long arm is rich in duplicons that, define five breakpoints (BP) for 15q rearrangements. 15q11.2 microdeletion between BP1 and BP2 has been previously associated with developmental delay and atypical psychological patterns. This region contains four highly-conserved and non-imprinted genes: NIPA1, NIPA2, CYFIP1, TUBGCP5. Our goal was to investigate the phenotypes associated with this microdeletion in a cohort of 52 patients. This copy number variation (CNV) was prevalent in 0.8% patients presenting with developmental delay, psychological pattern issues and/or multiple congenital malformations. This was studied by array-CGH at six different French Genetic laboratories. We collected data from 52 unrelated patients (including 3 foetuses) after excluding patients with an associated genetic alteration (known CNV, aneuploidy or known monogenic disease). Out of 52 patients, mild or moderate developmental delay was observed in 68.3%, 85.4% had speech impairment and 63.4% had psychological issues such as Attention Deficit and Hyperactivity Disorder, Autistic Spectrum Disorder or Obsessive-Compulsive Disorder. Seizures were noted in 18.7% patients and associated congenital heart disease in 17.3%. Parents were analysed for abnormalities in the region in 65.4% families. Amongst these families, 'de novo' microdeletions were observed in 18.8% and 81.2% were inherited from one of the parents. Incomplete penetrance and variable expressivity were observed amongst the patients. Our results support the hypothesis that 15q11.2 (BP1-BP2) microdeletion is associated with developmental delay, abnormal behaviour, generalized epilepsy and congenital heart disease. The later feature has been rarely described. Incomplete penetrance and variability of expression demands further assessment and studies.
Assuntos
Deficiências do Desenvolvimento/genética , Epilepsia/genética , Cardiopatias/genética , Deficiência Intelectual/genética , Transtornos Mentais/genética , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Adolescente , Adulto , Transtorno do Deficit de Atenção com Hiperatividade/genética , Proteínas de Transporte de Cátions , Criança , Transtornos Globais do Desenvolvimento Infantil/genética , Pré-Escolar , Aberrações Cromossômicas , Deleção Cromossômica , Cromossomos Humanos Par 15/genética , Estudos de Coortes , Hibridização Genômica Comparativa , Variações do Número de Cópias de DNA , Deficiências do Desenvolvimento/diagnóstico , Epilepsia/diagnóstico , Feminino , Cardiopatias/congênito , Cardiopatias/diagnóstico , Humanos , Hibridização in Situ Fluorescente , Lactente , Deficiência Intelectual/diagnóstico , Masculino , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Transtornos Mentais/diagnóstico , Proteínas Associadas aos Microtúbulos/genética , Proteínas Associadas aos Microtúbulos/metabolismo , Pessoa de Meia-Idade , Fenótipo , Distúrbios da Fala/genética , Adulto JovemRESUMO
The introduction of molecular karyotyping technologies into the diagnostic work-up of patients with congenital disorders permitted the identification and delineation of novel microdeletion and microduplication syndromes. Interstitial 16p13.3 duplication, encompassing the CREBBP gene, which is mutated or deleted in the Rubinstein-Taybi syndrome, have been proposed to cause a recognisable syndrome with variable intellectual disability, normal growth, mild facial dysmorphism, mild anomalies of the extremities, and occasional findings such as developmental defects of the heart, genitalia, palate or the eyes. We here report the phenotypic and genotypic delineation of 9 patients carrying a submicroscopic 16p13.3 duplication, including the smallest 16p13.3 duplication reported so far. Careful clinical assessment confirms the distinctive clinical phenotype and also defines frequent associated features : marked speech problems, frequent ocular region involvement with upslanting of the eyes, narrow palpebral fissures, ptosis and strabismus, frequent proximal implantation of thumbs, cleft palate/bifid uvula and inguinal hernia. It also confirms that CREBBP is the critical gene involved in the duplication 16p13.3 syndrome.
