Re: TTS - Vascular connections
From: James Smeltzer (James.Smeltzer@wellstar.org)
Fri Mar 25 05:23:57 2005
I believed Benirschke found this as a fact. A review I have not read yet will shed light - I've ordered it:
The biology of the twinning process: how placentation influences outcome.
Benirschke K.
Semin Perinatol. 1995 Oct;19(5):342-50.
Department of Pathology, University of California, San Diego 92103-8321, USA.
Placentation of twins has important bearing on the fetal development and neonatal outcome. Because of limitation in space of the endometrial cavity, twin placentas frequently collide during their expansion. This may restrict their growth and also lead to a somewhat increased rate of placenta previa. Moreover, abnormal cord insertions such as marginal and velamentous cords are much more frequent in multiple gestation. Absence of one umbilical artery is also much more frequent in twins. The best prognosis is had when two independent placentas develop, the dichorionic separate organs. Fusion of two separate placentas does not lead to vascular anastomoses in human twins, whereas it often does in other species (marmoset, cattle). Blood vessel fusion occurs only in monochorionic twins, all of which are "identical" (monozygotic). Large anastomoses (usually artery-to-artery) allow blood to shift rapidly from one to the other. Thus, when one twins dies, the survivor may quickly exsanguinate into the dead twin, leading to hypotension and occasionally to cerebral palsy. Arteriovenous anastomoses are the basis for the twin transfusion syndrome. This results in severe prematurity and gross discordance of all sorts of physical parameters. Knowing this type of vascular shunts helped develop the prenatal laser obliteration with salvage of the twins. The worst prognosis occurs with the rarest type of placentation in twin, in which both reside in the same cavity. This is the monoamnionic-monochorionic twin placentation. By moving about, the twins often entangle their umbilical cords and some 40% to 50% may die in utero.
BTW this is a reference to the case I remembered:
Monozygotic twins with 45,X/46,XY mosaicism discordant for phenotypic sex.
Costa T, Lambert M, Teshima I, Ray PN, Richer CL, Dallaire L.
Am J Med Genet. 1998 Jan 6;75(1):40-4.
Department of Pediatrics, The Hospital for Sick Children, Toronto, Canada.
But it turns out there are many others. This emphasizes that the observation of monochorionicity does NOT imply identical karyotype for each twin. Jim
Monozygotic twins discordant for sex.
Schmidt R, Sobel EH, Nitowsky HM, Dar H, Allen FH Jr.
J Med Genet. 1976 Feb;13(1):64-8.
Molecular and cytogenetic study on a case of monozygotic twins of discordant sex both with 47,X,idic(Yp)x2/45,X/46,X,idic(Yp) mosaicism.
Hoshi N, Minobe S, Okuyama K, Fujimoto S
Department of Obstetrics and Gynecology, Hokkaido University School of Medicine, Sapporo, Japan.
Teratology 1998 Mar;57(3):23A
Some causes of genotypic and phenotypic discordance in monozygotic twin pairs.
Machin GA.
Am J Med Genet. 1996 Jan 22;61(3):216-28.
Comment in:
Am J Med Genet. 2001 Aug 15;102(3):306-7 PMID: 11484214.
Department of Laboratory Medicine and Pathology, University of Alberta Hospitals, Edmonton, Canada.
Monozygotic twins with discordant sex.
Kurosawa K, Kuromaru R, Imaizumi K, Nakamura Y, Ishikawa F, Ueda K, Kuroki Y.
Acta Genet Med Gemellol (Roma). 1992;41(4):301-10.
Division of Medical Genetics, Kanagawa Children's Medical Center, Japan.
Sexual discordance in monozygotic twins.
Perlman EJ, Stetten G, Tuck-Müller CM, Farber RA, Neuman WL, Blakemore KJ, Hutchins GM.
Am J Med Genet. 1990 Dec;37(4):551-7.
Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, MD 21205.
Monozygotic twins with dissimilar phenotypes and chromosome complements.
Pedersen IK, Philip J, Sele V, Starup J.
Acta Obstet Gynecol Scand. 1980;59(5):459-62.
Monozygotic twins of discordant sex both with 45,X/46,X,idic(Y) mosaicism.
Fujimoto A, Boelter WD, Sparkes RS, Lin MS, Battersby K.
Am J Med Genet. 1991 Nov 1;41(2):239-45.
Genetics Division, Los Angeles County/University of Southern California Medical Center 90033.
Prenatal diagnosis of heterokaryotypic mosaic twins discordant for fetal sex.
Schmid O, Trautmann U, Ashour H, Ulmer R, Pfeiffer RA, Beinder E.
Prenat Diagn. 2000 Dec;20(12):999-1003.
Department of Obstetrics and Gynaecology, Friedrich-Alexander-University Erlangen-Nuremberg, Germany.
The presence of a monozygotic twin gestation with discordant sex of the twins is a very rare constellation, which is referred to as heterokaryotypic monozygotic pregnancy.
Monozygotic twins of opposite sex.
Wachtel SS, Somkuti SG, Schinfeld JS.
Cytogenet Cell Genet. 2000;91(1-4):293-5.
Division of Reproductive Genetics, Department of Obstetrics and Gynecology, University of Tennessee, Memphis TN 38103, USA. swatchtel@utmem.edu
Monozygotic twins with discordant sexual phenotypes due to different ratios of mosaicism of 47,X,idic(Y),idic(Y)/46,X, idic(Y)/45,X.
Nonomura K, Kakizaki H, Fukuzawa N, Fujieda K, Harada N, Niikawa N, Koyanagi T.
Endocr J. 2002 Aug;49(4):497-501.
--
James S. Smeltzer, MD, FACOG, SMFM
Consultant, Maternal Fetal Medicine
Wellstar Physicians' Group
Northwest Women's Care
787 Campbell Hill St
Marietta GA 30060
James.Smeltzer@wellstar.org
VM 678-290-3035
Off 770-528-0260
Page 404-318-3451
>>> "DuBose, Terry" <DuboseTerryJ@uams.edu> 3/24/2005 1:28:16 PM >>>
Thanks... I am not sure I understand this: "TTTS is more frequent the
fewer vascular connections (or AV vascular connections) between twins."
That seems counterintuitive to me. Would not the effects of TTTS be
worse if there were more or larger vascular connections between the
twins?
Terry J. DuBose, M.S., RDMS, FSDMS, FAIUM
Associate Professor & Director
Diagnostic Medical Sonography Program
University of Arkansas for Medical Sciences, CHRP
4301 West Markham St. Mail Slot #563
Little Rock, Arkansas, 72205 USA
501-686-6510
DuBoseTerryJ@UAMS.edu
http://www.io.com/~dubose/
http://www.uams.edu/chrp/dms/default.asp
http://www.obgyn.net/us/panel/panel.htm
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-----Original Message-----
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From: James Smeltzer [mailto:James.Smeltzer@wellstar.org]
Sent: Thursday, March 24, 2005 11:36 AM
To: DuBose, Terry
Subject: Re: TTS
Nice case. I'll keep you in mind. TTTS is more frequent the fewer
vascular connections (or AV vascular connections) between twins.
Jim
--
James S. Smeltzer, MD, FACOG, SMFM
Consultant, Maternal Fetal Medicine
Wellstar Physicians' Group
Northwest Women's Care
787 Campbell Hill St
Marietta GA 30060
James.Smeltzer@wellstar.org
VM 678-290-3035
Off 770-528-0260
Page 404-318-3451
>>> DuboseTerryJ@uams.edu 3/21/2005 11:08:45 AM >>>
Dr. Fougner,
We once had a case of discordant twins at 6 weeks. I discussed this
case as it related to the embryonic heart rates because at 6 LMP weeks
they were almost one week different in CRL ages, but the EHR ages were
appropriate to each CRL age.
See the bottom of: http://www.obgyn.net/us/cotm/0001/ehr2000.htm
We followed them throughout gestation and they were delivered
spontaneously shortly after the 34th week exam. The twins remained
about one week discordant through out gestation, but normal. The
path
report on the placenta read in part:
"... roughly discoid twin placenta which is approximately 25 x 20 x 4
cm
and which has attached glistening gray-pink fetal membranes which are
fused in the center of the fetal surface to from a thin, translucent
partition." There were, "Vascular channels from side 'A' cross the
membranous partition onto the fetal surface of side 'B'." It is also
noteworthy that the umbilical cords were quite different. Umbilical
cord "A" was inserted 5.5 cm from the nearest placental margin and was
twice the diameter of cord "B". Cord "B" had a velamentous insertion
at
the other side of the placenta. The pathology report concluded,
"Third
trimester diamniotic, monochorionic twin placenta with attached
trivascular umbilical cords (two)."
"The mother informed us that the smaller twin had some respiratory
illness during the first six months, but the larger, twin A, had no
problems. Both were doing well at their first birthday."
From, and for more complete discussion of this case: DuBose; FETAL
SONOGRAPHY; W. B. Saunders 1996, p. 151-154. Note, the mother signed
a
release of all records pertaining to this pregnancy, including a
release
for publication.
I am not sure this set of twins qualifies as true TTS, though it may
be
a very mild form.
The initial 6 week study came as we were deep in our investigation of
the EHR and age. It was particularly interesting that the CRLs and
EHRs
remained in good predicted relationship as they went over the peak of
the EHR curve at 9 weeks. Before 9 weeks the larger twin had the
faster
heart rate, but after 9 weeks the larger twin had the slower heart
rate
until the 16th week.
Their mother brought the twins by our office every year on their
birthday until they were three years old. They twins remained
discordant in size until that time, but I have lost contact with the
family since I left Texas in 1996.
Do you have CRLs and EHRs for your case? I find those very
interesting
in these very early cases.
Let us have followup on what you find.
Terry J. DuBose, M.S., RDMS, FSDMS, FAIUM
Associate Professor & Director
Diagnostic Medical Sonography Program
University of Arkansas for Medical Sciences, CHRP
4301 West Markham St. Mail Slot #563
Little Rock, Arkansas, 72205 USA
501-686-6510
DuBoseTerryJ@UAMS.edu
http://www.io.com/~dubose/
http://www.uams.edu/chrp/dms/default.asp
http://www.obgyn.net/us/panel/panel.htm
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-----Original Message-----
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From: ultrasound@obgyn.net [mailto:ultrasound@obgyn.net] On Behalf Of
evsono@pipeline.com
Sent: Friday, March 18, 2005 7:49 AM
To: Multiple recipients of list ULTRASOUND
Subject: TTS
What is the earliest gestational age anyone has suspected a case of
TTS?
art
--
art fougner, md
"If you don't know where you are going, you will wind up somewhere
else."
Lawrence Peter Berra
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