遺傳性耳聾的產(chǎn)前診斷與遺傳咨詢

劉暢 丁紅珂 吳菁 麥明琴 張彥 曾玉坤 劉玲 劉舒 尹愛華

(廣東省婦幼保健院，廣東 廣州 511442)

遺傳性耳聾的產(chǎn)前診斷與遺傳咨詢

劉暢 丁紅珂 吳菁 麥明琴 張彥 曾玉坤 劉玲 劉舒 尹愛華*

(廣東省婦幼保健院，廣東 廣州 511442)

目的 耳聾是臨床上常見的出生缺陷之一，大多數(shù)耳聾患兒家長(zhǎng)對(duì)于耳聾的遺傳檢測(cè)及產(chǎn)前診斷持積極態(tài)度。方法 對(duì)117例非綜合征型感音神經(jīng)性耳聾患兒家庭進(jìn)行耳聾基因檢測(cè)，輔以恰當(dāng)?shù)倪z傳咨詢，并為有再生育需求的家庭提供產(chǎn)前基因診斷。結(jié)果 通過基因檢測(cè)為57例患兒找到明確致聾基因突變，并將致聾位點(diǎn)及遺傳模式在每個(gè)患兒家庭中進(jìn)行分析驗(yàn)證。接受詳細(xì)的遺傳咨詢后，53對(duì)攜帶常染色體隱性遺傳致聾突變的夫婦選擇產(chǎn)前基因診斷。出生后聽力評(píng)估結(jié)果與產(chǎn)前診斷結(jié)果相符。結(jié)論 本臨床研究中，94.6%攜帶常染色體隱性遺傳致聾基因突變的夫婦選擇接受產(chǎn)前基因診斷，提示絕大多數(shù)耳聾患兒的家長(zhǎng)對(duì)于耳聾的遺傳檢測(cè)及產(chǎn)前診斷持積極態(tài)度，認(rèn)為產(chǎn)前基因檢測(cè)有助于家長(zhǎng)從心理、經(jīng)濟(jì)、醫(yī)療等角度提前做好準(zhǔn)備。

耳聾；產(chǎn)前診斷；遺傳咨詢

耳聾是臨床上常見的出生缺陷之一，每1000名活產(chǎn)兒中便有1～3名新生聾兒[1,2]。在未全面開展早期聽力檢測(cè)計(jì)劃前，患兒聽力缺失多在1.5～3歲間被發(fā)現(xiàn)，但已錯(cuò)過了學(xué)語的重要時(shí)期[1,3]。由于幼兒期大腦可塑性的改變，在這一重要時(shí)期未獲得充分的聽覺刺激及語言接觸的孩童將面臨包括語言獲取、認(rèn)知發(fā)展、社會(huì)心理發(fā)展及社會(huì)交往能力等多方面的障礙[4-6]。據(jù)報(bào)道，絕大多數(shù)耳聾患兒的家長(zhǎng)對(duì)于耳聾的遺傳檢測(cè)及產(chǎn)前診斷持積極態(tài)度[7-9]。產(chǎn)前基因檢測(cè)有助于患兒家長(zhǎng)及早從心理、經(jīng)濟(jì)、醫(yī)療等角度為受累患兒做好醫(yī)療及特殊教育的準(zhǔn)備。在這個(gè)過程中，恰當(dāng)?shù)倪z傳咨詢十分重要[10]。遺傳咨詢的內(nèi)容需包括疾病的性質(zhì)、突變攜帶的意義、遺傳模式及再發(fā)風(fēng)險(xiǎn)等。

1 材料與方法

1.1 基本資料 本臨床研究將117個(gè)曾生育非綜合征型感音神經(jīng)性耳聾患兒的家庭納入研究范圍，入組家庭均為在廣東省婦幼保健院醫(yī)學(xué)遺傳中心門診尋求耳聾基因診斷和遺傳咨詢的耳聾患兒家庭。研究方法和研究對(duì)象入組標(biāo)準(zhǔn)經(jīng)廣東省婦幼保健院倫理委員會(huì)審核通過。在受檢者(監(jiān)護(hù)人)充分知情同意情況下，簽署知情同意書。臨床上對(duì)入組家庭進(jìn)行病史收集及體格檢查，包括詳細(xì)的過往病史、耳聾家族史、聽力學(xué)檢查情況、發(fā)病年齡及誘因、感染史、氨基糖苷類藥物接觸史等。

1.2 研究方法 采集耳聾患兒及其父母的外周血，提取基因組DNA。通過晶芯TM9項(xiàng)遺傳性耳聾基因檢測(cè)試劑盒進(jìn)行突變熱點(diǎn)的初篩，對(duì)于檢出單等位基因致聾突變的患兒，進(jìn)行相應(yīng)基因及可能相互作用復(fù)合致聾的相關(guān)基因的序列分析；對(duì)于初篩未檢出致聾突變的患兒，進(jìn)行GJB2基因、SLC26A4基因、線粒體12SrRNA等耳聾基因的編碼區(qū)序列測(cè)定及分析。對(duì)患兒父母進(jìn)行相應(yīng)致聾基因序列分析，以驗(yàn)證致聾基因突變并進(jìn)行遺傳分析。

綜合分析耳聾患兒的臨床表現(xiàn)及基因檢測(cè)結(jié)果，為每個(gè)入組家庭提供詳細(xì)的遺傳咨詢及生活指導(dǎo)[10,12-14]，包括聾病性質(zhì)、致聾因素、遺傳模式、干預(yù)方式等。對(duì)于有再生育需求的家庭，提供再發(fā)風(fēng)險(xiǎn)分析及生育指導(dǎo)，包括胚胎植入前診斷、接受捐贈(zèng)配子、產(chǎn)前基因診斷等。對(duì)于準(zhǔn)備接受耳聾產(chǎn)前診斷的家庭，在遺傳咨詢中需包含胎兒取材術(shù)的手術(shù)流程、技術(shù)風(fēng)險(xiǎn)、檢測(cè)局限性等內(nèi)容[15]。

對(duì)于選擇接受耳聾基因產(chǎn)前診斷的家庭，在夫妻雙方充分知情同意情況下，經(jīng)超聲介導(dǎo)行絨毛穿刺術(shù)或羊膜腔穿刺術(shù)取得胎兒樣本，進(jìn)行產(chǎn)前基因檢測(cè)[16]。胎兒樣本采集過程經(jīng)廣東省婦幼保健院倫理委員會(huì)審核通過。為避免手術(shù)過程中母體細(xì)胞對(duì)羊水、絨毛等胎兒樣本造成污染[17,18]，影響產(chǎn)前基因檢測(cè)結(jié)果，我們通過熒光定量PCR檢測(cè)13、18、21號(hào)染色體上的13個(gè)微衛(wèi)星多態(tài)標(biāo)記以鑒別污染。

2 結(jié) 果

經(jīng)基因檢測(cè)，發(fā)現(xiàn)本臨床研究所收集的117例非綜合征型感音神經(jīng)性耳聾患兒中，62例攜帶常染色體隱性遺傳致聾突變位點(diǎn)，其中56例攜帶雙等位基因致聾突變或復(fù)合雜合突變，6例僅檢出單等位基因致聾位點(diǎn)，致聾位點(diǎn)及遺傳模式在每個(gè)患兒家庭中經(jīng)分析、驗(yàn)證。接受詳細(xì)的遺傳咨詢后，53對(duì)攜帶致聾突變的夫婦選擇接受產(chǎn)前基因診斷。如表1所示，10例胎兒未攜帶致聾突變、32例攜帶單等位基因致聾突變位點(diǎn)、11例攜帶雙等位基因致聾突變或復(fù)合雜合突變。根據(jù)耳聾基因產(chǎn)前診斷的結(jié)果，為各家庭提供相應(yīng)的遺傳咨詢及生活指導(dǎo)。出生后聽力評(píng)估結(jié)果與產(chǎn)前診斷結(jié)果相符。此外，3對(duì)攜帶常染色體隱性遺傳致聾突變的夫婦經(jīng)充分知情同意后選擇不進(jìn)行耳聾基因產(chǎn)前診斷，其中一對(duì)夫婦生育聽力缺失患兒，我們?yōu)槠涮峁┰缙谠\斷、干預(yù)及援助信息。

表1 曾生育耳聾患兒且已明確夫婦均攜帶常染色體隱性遺傳致聾基因突變的家庭行產(chǎn)前診斷的結(jié)果

續(xù)表1

續(xù)表1

此外，一位耳聾患兒經(jīng)檢測(cè)發(fā)現(xiàn)攜帶線粒體DNA 12S rRNA 1555A>G同質(zhì)性突變。該患兒自一歲半因肺炎接受常規(guī)劑量慶大霉素治療后出現(xiàn)重度感音神經(jīng)性耳聾。鑒于線粒體DNA 12S rRNA 1555A>G突變是氨基糖苷類藥物遺傳易感性的重要機(jī)制[19]且遵循母系遺傳模式，我們?yōu)樵摶純旱哪赶涤H屬提供了詳細(xì)的用藥指導(dǎo)。

3 討 論

在遺傳檢測(cè)過程中，客觀、恰當(dāng)?shù)倪z傳咨詢十分重要。一般來說，遺傳咨詢需包括檢測(cè)前咨詢與檢測(cè)后咨詢部分[10]。耳聾基因檢測(cè)前的遺傳咨詢需涉及聾病性質(zhì)、致聾因素、遺傳方式、檢測(cè)手段及各種檢測(cè)方法的優(yōu)勢(shì)、劣勢(shì)、風(fēng)險(xiǎn)等。檢測(cè)后咨詢需在檢測(cè)前咨詢的基礎(chǔ)上對(duì)檢測(cè)結(jié)果進(jìn)行分析與解釋，并對(duì)檢測(cè)結(jié)果所產(chǎn)生的心理影響做出評(píng)估，必要時(shí)為病患家庭提供心理疏導(dǎo)機(jī)構(gòu)信息。

本臨床研究中，94.6%攜帶常染色體隱性遺傳致聾基因突變的夫婦選擇接受產(chǎn)前基因診斷，提示大多數(shù)耳聾患兒的家長(zhǎng)對(duì)于耳聾的遺傳檢測(cè)及產(chǎn)前診斷持積極態(tài)度，認(rèn)為產(chǎn)前基因檢測(cè)有助于家長(zhǎng)從心理、經(jīng)濟(jì)、醫(yī)療等角度提前做好準(zhǔn)備。對(duì)于產(chǎn)前診斷結(jié)果及患病胎兒去留的態(tài)度則受多方面因素影響，包括倫理道德標(biāo)準(zhǔn)、宗教信仰、文化程度、經(jīng)濟(jì)條件以及管理相關(guān)領(lǐng)域的法律法規(guī)。

此外，本臨床研究中的117例耳聾患兒均出生于聽力正常的家庭，其中103例無耳聾家族史。鑒于耳聾是臨床上最常見的出生缺陷，每1000名活產(chǎn)兒中便有1～3名新生聾兒，而90%～95%的耳聾患兒出生于聽力正常的家庭[20]，明確正常聽力人群耳聾基因的攜帶率與突變譜對(duì)于耳聾防控具有重要意義。

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編輯：宋文穎

Objective Genetic counseling and prenatal diagnosis are very necessary to detect hereditary hearing loss, especially in high-risk families. Prenatal diagnosis gives parents the chance to prepare psychologically, financially and medically for the probable health and educational needs of the affected neonates. Method 117 unrelated families with children affected with non-syndromic sensorineural hearing loss were enrolled in the study and received genetic analysis with microarray and DNA sequencing technologies. Genetic counseling was provided to each participating families, and prenatal diagnosis was given to those at risk and would like to know their fetuses' genotypes and probable hearing statuses. Results 57 cases in the present study were diagnosed with confirmed pathogenic mutations and clear inheritance patterns. After receiving genetic counseling, 53 carrier couples with pathogenic mutations chose to proceed prenatal diagnosis, the results of which were in accordance with the pregnancy outcomes. Infants prenatally detected to be monoallelic mutation carriers and those harbored neither deafness-causing mutations form their parents passed newborn hearing screening and six month follow-ups, while neonates prenatally detected to be carriers of diallelic or compound heterozygous mutations developed hearing loss after birth. Conclusions With appropriate genetic counseling and support services provided, the genetic testing and the prenatal diagnosis of hearing loss were valued by carrier couples for the information provided for future family planning and probably the preparation for the health and educational needs of the affected neonates.

hearing loss; genetic counseling; prenatal diagnosis

10.13470/j.cnki.cjpd.2015.04.009

*通訊作者：尹愛華，E-mail：yinaiwa@vip.126.com

R714.55

A

2015-09-07)