Hypoplasia of the nasal bone in trisomy 21

[bulletproof]

Hi all,
I am posting here for a friend who received some disturbing news today regarding her pregnancy. She is at eighteen weeks gestation, and her ultrasound showed a present but hypoplastic nasal bone. She is 35, and this is her fourth pregnancy. Her ob/gyn discussed with her the possibility of trisomy 21, and offered her abortion, amniocentesis etc. She declined all , and is now frantic about the possibility of having a Downs child. Could the residents or attendings in the know on this board please comment with respect to the PPV of this specific and isolated finding. There were no other abnormalities on ultrasound. Incidentally, her other children were all born with short stubby little noses. The Ob/gyn said this marker was only 1-2 yrs old and thus he could not comment on similarities between this and her prior pregnancies. I thank you all for your input in advance. Please respond, as one way or the other I would like to be able to give my friend some information. Thank you.

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[Skeptic]

Hi all,
I am posting here for a friend who received some disturbing news today regarding her pregnancy. She is at eighteen weeks gestation, and her ultrasound showed a present but hypoplastic nasal bone. She is 35, and this is her fourth pregnancy. Her ob/gyn discussed with her the possibility of trisomy 21, and offered her abortion, amniocentesis etc. She declined all , and is now frantic about the possibility of having a Downs child. Could the residents or attendings in the know on this board please comment with respect to the PPV of this specific and isolated finding. There were no other abnormalities on ultrasound. Incidentally, her other children were all born with short stubby little noses. The Ob/gyn said this marker was only 1-2 yrs old and thus he could not comment on similarities between this and her prior pregnancies. I thank you all for your input in advance. Please respond, as one way or the other I would like to be able to give my friend some information. Thank you.

Hi, no professional, just a MS3. I don't know of any gold-standard studies out there that have looked at the PPV of hypoplastic nasal bones and trisomy 21, but I think that is a moot point. I think your friend needs to seriously consider prenatal genetic testing to verify whether or not a chromosomal abnormality exists. There is no hiding the fact that she is of advanced maternal age, and thereby has an increased risk for a child with Trisomy 21. The debate over abortion is not warranted here, and I don't think should be an issue. The decision should be left up to your friend and her husband. I think they would be able to make the most comprehensive decision only when they have stronger evidence suggestive of a real abnormality, rather than a hypoplastic nose (which I believe is also known as saddle nose defect which is associated with a variety of condition). You must also consider the validity of the statement made by the OB/GYN and ensure that there is a real correlation with hypoplastic nose and Trisomy 21. In a nutshell, get the amnio or chorionic villus sampling and then they should decided whether to abort, put up for adoption, or keep the child, and if they decide to keep, to be prepared and educated in the parenting of a child with disability. Hope this helps. Best of luck to your friend.

 

[tiredmom]

In a nutshell, get the amnio or chorionic villus sampling and then they should decided whether to abort, put up for adoption, or keep the child, and if they decide to keep, to be prepared and educated in the parenting of a child with disability. Hope this helps. Best of luck to your friend.

Well said! I would also suggest your friend talk to parents of children with Down's syndrome - and not just one set. Of the parents I know of kids with special needs (and I've met several, my son's been in special ed for the last 7 years) - we are always ready and willing to talk to someone who may be in the same boat. Life is not over if the child does have down's, or something else. There's a poem that's always been helpful to me when I start to feel down, I can't recall the name... something about Welcome to Holland.
Good luck to them.

 

[DrBuzzLightYear]

here's an idea! how about we answer her question!

Obstet Gynecol. 2004 Dec;104(6):1229-33.
The association between fetal nasal bone hypoplasia and aneuploidy.

Odibo AO, Sehdev HM, Dunn L, McDonald R, Macones GA.

University of Pennsylvania Medical Center, Pennsylvania Hospital, and Chestnut Hill Hospital, Philadelphia, Pennsylvania, USA. [email protected]

OBJECTIVE: To determine the association between fetal nasal bone hypoplasia and aneuploidy in women undergoing prenatal diagnosis. METHODS: A prospective cohort study involving women undergoing chorionic villus sampling and amniocentesis for an increased risk of aneuploidy. Fetal biometric and nasal bone measurements were obtained at the time of prenatal diagnosis and compared with karyotypes. Nasal bone hypoplasia was defined as nasal bone less than 2.5th percentile for the gestational age. RESULTS: A total of 632 fetuses were evaluated. Twenty-nine (4.6%) had an aneuploidy (18 trisomy 21, 5 trisomy 18, 1 Turner's syndrome, one Marker chromosome 1, 2 sex chromosome anomalies, and 2 triploidy). Nasal bone measurements were documented in 29 aneuploid fetuses. The nasal bone was either absent or hypoplastic in 12 of 29 (41%) fetuses with aneuploidy and in 8 of 18 (44%) with trisomy 21. By using receiver operating characteristics curves, the optimal threshold of nasal bone hypoplasia associated with fetal aneuploidy was a biparietal diameter/nasal bone ratio of 11 or greater. The sensitivity, specificity, and positive and negative predictive values for the detection of fetal aneuploidy were 50%, 93%, 24%, and 98%, respectively. CONCLUSION: Absent or hypoplastic nasal bone is a marker for fetal aneuploidy in a high-risk population. However, this marker needs to be evaluated by larger prospective studies in low-risk populations before adoption for clinical use.

 

[tiredmom]

here's an idea! how about we answer her question!

Not to be a grouch, but everything contributed would be helpful. I'm glad you had time to look up a study. It sounds like the person is not considering termination, so best to prepare for what may come. With the sensitivity and PPV listed, it really won't tell her that it will or won't have downs - so she still needs to prepare mentally.