Prenatal diagnosis and genetic analysis of 9p24 microdeletion in six fetuses / 中华围产医学杂志

Objective:To investigate the prenatal diagnosis and genetic analysis of 9p24 microdeletion in six fetuses.Methods:Genetic data of six pregnant women with positive results of serological Down's syndrome screening at Henan Provincial People's Hospital from January 2018 to January 2020 were retrospectively collected and analyzed. Amniotic fluid and the parents' peripheral blood samples were subjected to G banding and array comparative genomic hybridization (aCGH) analysis. Detected copy number variation (CNV) were classified based on the American College of Medical Genetics and Genomics (ACMG) scoring standard.Results:Six fetuses showed no abnormalities in ultrasound during the second trimester as well as in karyotyping. A chromosome deletion of 1 019~6 001 kb at 9p24 was found in all six fetuses by aCGH, referring to disease-related genes DMRT1, SMARCA2, DOCK8, etc. The deletion of case 3 was inherited from the asymptomatic father, and the other fetal five were all de novo mutations. Cases 1, 2, 5, and 6 were pathogenic/likely pathogenic CNV carriers and cases 3 and 4 were CNV of unknown clinical significance carriers. After genetic counseling, cases 1, 2, 5, and 6 chose to terminate the pregnancies; cases 3 and 4 continued and gave birth to normal offspring. Conclusions:Fetuses with 9p24 microdeletion lack specific phenotypes before born. DMRT1 and SMARCA2 may be the key genes in this region.

Polimorfismo del cromosoma 9. Presentación de dos casos / Polymorphism of chromosome 9. Presentation of two cases

Las variantes polimórficas en los cromosomas 1, 9, 16, y en el cromosoma Y son más frecuentes en la persona infértil que en la población general; la presencia de estas variantes en uno o ambos miembros de la pareja podría incrementar la frecuencia de infertilidad de causa idiopática. El cromosoma 9 es estructuralmente muy polimórfico y contiene la región más larga de heterocromatina que hay en los seres humanos. Por tales razones y por la indiscutible importancia que cobra el estudio citogenético en varones con alteraciones seminales severas, como parte del diagnóstico certero y oportuno de la pareja con fallo reproductivo, se presentan los casos de dos pacientes que fueron atendidos en el Centro Territorial de Reproducción Asistida de Cienfuegos, para estudio de una infertilidad. Se les realizó estudio citogenético y se diagnosticó polimorfismo del cromosoma 9.

Polymorphic variants on chromosomes 1, 9, 16, and on the Y chromosome are more frequent in the infertile person than in the general population; the presence of these variants in one or both members of the couple could increase the frequency of idiopathic cause infertility. Chromosome 9 is structurally highly polymorphic and contains the longest region of heterochromatin in humans. For these reasons and because of the indisputable importance of the cytogenetic study in men with severe seminal disorders, as part of the accurate and timely diagnosis of the couple with reproductive failure, the cases of two patients who were treated at the Cienfuegos Regional Center of Assisted Reproduction , for an infertility study. A cytogenetic study was performed and chromosome 9 polymorphism was diagnosed.

New report of two patients with mosaic trisomy 9 presenting unusual features and longer survival / Novo relato de dois pacientes com a trissomia do 9 em mosaico apresentando achados não usuais e uma sobrevida prolongada

CONTEXT: Mosaic trisomy 9 is considered to be a rare chromosomal abnormality with limited survival. Our objective was to report on two patients with mosaic trisomy 9 presenting unusual findings and prolonged survival. CASE REPORTS: The first patient was a boy aged six years and five months presenting weight of 14.5 kg (< P3), height of 112 cm (P10), head circumference of 49 cm (P2), prominent forehead, triangular and asymmetric face, thin lips, right microtia with overfolded helix, small hands, micropenis (< P10), small testes and hallux valgus. His lymphocyte karyotype was mos 47,XY,+9 [4 ]/46,XY [50 ]. Additional cytogenetic assessment of the skin showed normal results. The second patient was a two-year-old girl who was initially assessed at five months of age, when she presented weight of 5.3 kg (< P3), height of 61.5 cm (P2-P10), head circumference of 40.5 cm (P25), sparse hair, micrognathia, right ear with overfolded helix and preauricular pit, triphalangeal thumbs and sacral dimple. She also had a history of congenital heart disease, hearing loss, hypotonia, delayed neuropsychomotor development and swallowing disorder. Her lymphocyte karyotype was mos 47,XX,+9 [3 ]/46,XX [69 ]. Both patients had unusual clinical findings (the first, hemifacial hypoplasia associated with microtia, with a phenotype of oculo-auriculo-vertebral spectrum, and the second, triphalangeal thumbs and hearing loss) and survival greater than what is usually described in the literature (< 1 year). Further reports will be critical for delineating the clinical features and determining the evolution of patients with mosaic trisomy 9.

CONTEXTO: A trissomia do cromossomo 9 em mosaico é considerada uma anormalidade cromossômica rara e com limitada sobrevida. Nosso objetivo foi realizar o relato de dois pacientes com trissomia do 9 em mosaico, apresentando achados não usuais e sobrevida prolongada. RELATO DE CASOS: O primeiro paciente era um menino de seis anos e cinco meses apresentando peso de 14,5 kg (< P3), altura de 112 cm (P10), perímetro cefálico de 49 cm (P2), proeminência frontal, face triangular e assimétrica, lábios finos, microtia à direita com hélix sobredobrado, mãos pequenas, micropênis (< P10), testículos pequenos e hálux valgo. Seu cariótipo em linfócitos foi mos 47,XY,+9 [4 ]/46,XY [50 ]. O estudo citogenético complementar da pele foi normal. A segunda paciente era uma menina de dois anos, avaliada inicialmente aos cinco meses, quando apresentava peso de 5,3 kg (< P3), estatura de 61,5 cm (P2-P10), perímetro cefálico de 40,5 cm (P25), cabelos esparsos, micrognatia, orelha direita com sobredobramento do hélix e fosseta pré-auricular, polegares trifalangeanos e fosseta sacral. Ela possuía também história de cardiopatia congênita, perda auditiva, hipotonia, atraso do desenvolvimento neuropsicomotor e distúrbio da deglutição. Seu cariótipo de linfócitos foi mos 47,XX,+9 [3 ]/46,XX [69 ]. Os dois pacientes apresentam achados clínicos não usuais (o primeiro, hipoplasia hemifacial associada à microtia lembrando um fenótipo de espectro óculo-aurículo-vertebral, e o segundo, polegares trifalangeanos e perda auditiva) e uma sobrevida maior àquela usualmente descrita na literatura (< 1 ano). Mais relatos serão fundamentais para delinear o quadro clínico e determinar a evolução de pacientes com trissomia do 9 em mosaico.