Published online September 1, 2004
PEDIATRICS
Vol. 114
No. 3
September 2004, pp.
e333-e336
(doi:10.1542/peds.2004-0045)
Computer-Aided Anthropometry in the Evaluation of Dysmorphic Children
Andreas Zankl, MD
From the Institute of Medical Genetics, University of Zurich, Zurich, Switzerland
 |
ABSTRACT
|
|---|
Objective. Although anthropometry is widely regarded as the
technique of choice for the evaluation of dysmorphic features
among children, it is only rarely used in clinical practice.
Possible reasons for this are the limited access of pediatricians
to appropriate reference values and the time-consuming way measurements
must be plotted onto growth charts. This article describes a
computer program that overcomes these problems and greatly facilitates
the use of anthropometric measurements in pediatric medicine.
Design. A computer program for PalmOS-based, handheld computers that compares entered anthropometric measurements with age- and gender-matched reference values was developed. The software is distributed free of charge and can be downloaded (www.medgen.unizh.ch/abase/).
Results. The ABase software contains age- and gender-matched reference values for 18 anthropometric measures frequently used for the evaluation of dysmorphic children. The proband's age is automatically calculated from the entered birth date and can be corrected for prematurity. Entered measurements are compared with the internal reference values; the results are displayed as percentile ranks or z scores and are plotted on digital growth charts.
Conclusions. The presented software makes anthropometric reference values easily accessible on the ward or in the clinic and greatly reduces the time needed to plot the measurements onto growth charts. This should promote more widespread use of anthropometry in pediatric medicine.
Key Words: anthropometry • dysmorphology • handheld computers • PDA
The diagnosis of genetic syndromes is based on the recognition of subtle morphologic anomalies, which in their entirety produce a syndrome's characteristic appearance. Dysmorphic features are usually evaluated by clinical inspection and reported with descriptive terms such as "low-set ears" or "wide-set eyes." However, this practice is highly subjective. The wide range of morphologic variations in the normal population often makes it difficult to draw clear distinctions between normal and abnormal findings. Furthermore, clinical impressions can be misleading. For example, the depressed nasal bridge of children with Down syndrome gives the impression of widely spaced eyes, whereas actually their eyes are set closer than in the normal population. Not surprisingly, many physicians are uneasy with the interpretation of minor morphologic anomalies and rightly so, because even specialists often disagree regarding the presence or absence of minor anomalies among dysmorphic children.1
Anthropometry is a simple, noninvasive, inexpensive technique that circumvents these problems. Measurements recorded for a patient can be compared with reference values obtained for the normal population, and any deviations from the normative values can be objectively expressed as percentile ranks or z scores. Measurements can be declared abnormal if they fall outside a predefined range, such as >2 SD above or below the mean or outside the 5th to 95th percentile range. There is widespread agreement that this is the technique of choice for the evaluation of dysmorphic features.2–4
Despite all of these benefits, anthropometry is rarely used in clinical practice. This is probably attributable to practical reasons; appropriate growth charts for the various body dimensions are not readily available on the ward or in the clinic, and taking the measurements and plotting them on the charts is time-consuming. To overcome both problems, I have developed ABase, a computer program for handheld computers that compares entered anthropometric measurements with a database of age- and gender-matched reference values, calculates the percentile rank, and displays the result either as text or as a digitized growth chart.5 Although the program was originally developed as a tool for clinical geneticists, I became aware that most dysmorphic children are initially evaluated by pediatricians. The aim of this article is thus to illustrate the use of ABase in the evaluation of a dysmorphic child.
|
METHODS
|
|---|
ABase (for anthropometric database) can be downloaded free of
charge at
www.medgen.unizh.ch/abase. The software runs on handheld
computers based on the PalmOS operating system (PalmOne Inc,
Milpitas, CA) (Fig
1) PalmOS (version 3.5 or higher), the MathLib
shared library, and 88 kB of free RAM are required. Installation
instructions are given on the website. Table
1 provides an overview
of the available growth charts. The references chosen are all
in common use in pediatrics and clinical genetics.
2–4 For more details on how the charts were calculated, see ref
5.
View larger version (141K):
[in this window]
[in a new window]
|
Fig 1. Example of a contemporary, PalmOS-based, handheld computer with the ABase software installed. The device is approximately the size of a pocket calculator.
|
|
|
RESULTS
|
|---|
Figures 2 through 5
illustrate how to use the software. After
launching the program, the user is asked to enter the proband's
gender and birth date (Fig
2) ABase calculates and displays
the proband's age in years and months (or weeks, for infants
up to 12 weeks of age). If the individual is <2 years of
age, then correction for gestational age is offered. After choosing
a chart (Table
1), the user is taken to a second screen, where
the measurements can be entered (Fig
3) Tapping the "i" symbol
in the upper right corner of the screen reveals additional information
on each measurement (eg, explanation of abbreviations, measuring
technique, landmarks, data sources, and covered age range).
When the user taps the "Calculate" button (or simply selects
another field), the program compares the entered measurements
with the age- and gender-matched reference values in its database
and calculates the corresponding percentile rank. If a measurement
falls beyond the 1st or 99th percentile, then the
z score is
displayed instead (
z scores represent multiples of the SD; for
example, a measurement that is 3 SD above the mean has a
z score
of 3). Tapping the small pen symbol that appears behind the
percentile rank brings up a graphical representation of the
result (Fig
4). The 5th, 25th, 50th, 75th, and 95th percentiles
of the reference population are displayed on the chart by default,
but other percentiles can be chosen from the preferences menu.
The scale of the chart is auto-matically adapted to avoid crowding.
The proband's measurement is indicated by a blinking dot. Tapping
anywhere on the screen takes the user back to the previous screen.
Other measurements for the same individual can be assessed by
choosing a different chart from the main menu (Fig
5). The individual's
age and gender are preserved. Measurements for a different individual
can be entered after choosing "New Individual" from the main
menu. The basic charts, which contain the measurements for height,
weight, and head circumference, offer 2 additional features.
First, because several good references exist, the user can choose
between reference values for the United States/Canada, Great
Britain, or Switzerland (Table
1). The choice is saved in the
program's preferences and remembered the next time the program
is run. Second, when the "Predict" button is tapped, the program
calculates the proband's target height on the basis of the parents'
height (midparental height + 6.5 cm for boys; midparental height
– 6.5 cm for girls).
View larger version (223K):
[in this window]
[in a new window]
|
Fig 2. Start screen. The user can choose the individual's birth date and gender and the chart to be used. For children up to 2 years of age, correction for gestational age is offered.
|
|
View larger version (223K):
[in this window]
[in a new window]
|
Fig 3. Chart screen. The user enters the measurements, and the program displays the percentile rank for each measurement. Tapping the pen symbol brings up a graphical representation of the result.
|
|
View larger version (239K):
[in this window]
[in a new window]
|
Fig 4. Growth chart screen. The percentile limits shown can be chosen in the preferences menu. The individual is represented by a blinking dot. Tapping anywhere on the screen returns the user to the previous screen.
|
|
View larger version (229K):
[in this window]
[in a new window]
|
Fig 5. Charts menu. To assess additional measurements for the same individual, the user can choose a different chart from the charts menu. Choosing "New Individual" lets the user examine a different individual.
|
|
|
DISCUSSION
|
|---|
ABase greatly facilitates the use of anthropometric measurements
for the evaluation of dysmorphic children. Handheld computers
are small enough to be carried in a shirt pocket on the ward
or in the clinic and thus make the growth charts available wherever
they are needed. Having the computer perform the percentile
rank calculations is not only faster but also more accurate
than manually plotting the measurements on paper-based growth
charts.
Percentile ranks or z scores obtained this way can be analyzed more extensively by using more advanced techniques such as pattern profiling and discriminant analysis, which can effectively lead to the diagnosis of dysmorphic syndromes on the basis of anthropometric measurements alone. As an example, Moore et al6 identified 6 craniofacial measurements that could differentiate individuals with and without prenatal alcohol exposure with 98% sensitivity and 90% specificity. Such examples demonstrate that anthropometry is a powerful tool for the evaluation of dysmorphic children. I hope that ABase will make this tool more widely available.
|
FOOTNOTES
|
|---|
Accepted Mar 22, 2004.
Address correspondence to Andreas Zankl, MD, Division of Molecular Pediatrics, Centre Hospitalier Universitaire Vaudois, Rue du Bugnon, 1011 Lausanne, Switzerland. E-mail: andreas.zankl{at}hospvd.ch
|
REFERENCES
|
|---|
- Holmes LB, Kleiner BC, Leppig KA, Cann CI, Munoz A, Polk BF. Predictive value of minor anomalies: part II: use in cohort studies to identify teratogens.
Teratology. 1987;36
:291
–297[CrossRef][Web of Science][Medline]
- Goodman RM, Gorlin RJ.
Atlas of the Face in Genetic Disorders. 2nd ed. St Louis, MO: Mosby; 1977
- Hall JG, Froster-Iskenius UG, Allanson JE.
Handbook of Normal Physical Measurements. Oxford, United Kingdom: Oxford University Press; 1989
- Jones KL, Smith DW.
Smith's Recognizable Patterns of Human Malformation. 5th ed. Philadelphia, PA: Saunders; 1997
- Zankl A, Molinari L. ABase: a tool for the rapid assessment of anthropometric measurements on handheld computers.
Am J Med Genet. 2003;121A
:146
–150
- Moore ES, Ward RE, Jamison PL, Morris CA, Bader PI, Hall BD. The subtle facial signs of prenatal exposure to alcohol: an anthropometric approach.
J Pediatr. 2001;139
:215
–219[CrossRef][Web of Science][Medline]
- Ogden CL, Kuczmarski RJ, Flegal KM, et al. Centers for Disease Control and Prevention 2000 growth charts for the United States: improvements to the 1977 National Center for Health Statistics version.
Pediatrics. 2002;109
:45
–60[Abstract/Free Full Text]
- Farkas LG.
Anthropometry of the Head and Face. New York, NY: Raven Press; 1994
- Freeman JV, Cole TJ, Chinn S, Jones PR, White EM, Preece MA. Cross sectional stature and weight reference curves for the UK, 1990.
Arch Dis Child. 1995;73
:17
–24[Abstract/Free Full Text]
- Prader A, Largo RH, Molinari L, Issler C. Physical growth of Swiss children from birth to 20 years of age: first Zurich longitudinal study of growth and development.
Helv Paediatr Acta Suppl. 1989;52
:1
–125[Medline]
- Zankl A, Eberle L, Molinari L, Schinzel A. Growth charts for nose length, nasal protrusion, and philtrum length from birth to 97 years.
Am J Med Genet. 2002;111
:388
–391[CrossRef][Web of Science][Medline]
- Feingold M, Bossert WH. Normal values for selected physical parameters: an aid to syndrome delineation.
Birth Defects Orig Artic Ser. 1974;10
:1
–16
- Sivan Y, Merlob P, Reisner SH. Upper limb standards in newborns.
Am J Dis Child. 1983;137
:829
–832[Abstract/Free Full Text]
- Merlob P, Sivan Y, Reisner SH. Anthropometric measurements of the newborn infant (27 to 41 gestational weeks).
Birth Defects Orig Artic Ser. 1984;20
:1
–52
- Blais MM, Green WT, Anderson M. Length of the growing foot.
J Bone Joint Surg. 1956;39A
:998
–1001
- Cole TJ. The LMS method for constructing normalized growth standards.
Eur J Clin Nutr. 1990;44
:45
–60[Web of Science][Medline]
PEDIATRICS (ISSN 1098-4275). ©2004 by the American Academy of Pediatrics
CiteULike 
Connotea 
Del.icio.us 
Digg 
Facebook 
Reddit 
Technorati 
Twitter What's this?
TOP
ABSTRACT
METHODS
