LOW BIRTH WEIGHT AND JOINT LAXITY /
HYPOTONIA IN DOWNS. IS THERE SOME RELATIONSHIP? AN OTHER EPIDEMIOLOGICAL
DEVELOPMENT OF TWO PRECEDING DIFFERENT INVESTIGATIONS ON A SERIES OF 510
SUBJECTS.
Renato COCCHI, neurologist and medical
psychologist
Summary.
From the same consecutive series of 510 Down
subjects, two subsamples were already extracted, the first of 142 subjects with
laxity / hypotonia, and the second of 56 Ss (17 F and 39 M; Distribution of the
chromosomal diagnoses a little altered as an artifact due to the reduced extent
of this sample) with low birth weight ( < 2500 grams ).
The whole data were crossed to appraise
the role of the low birth weight on the onset of laxity / hypotonia. No gender
prevalence was found between low birth weight and presence or absence of laxity
/ hypotonia. No relationship between low birth weight and laxity / hypotonia
was discovered.
Key words: Down syndrome; low birth weight;
joint laxity; hypotonia; stress; gender.
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Following my two preceding investigations on
the laxity / hypotonia (Cocchi, 2003 ) and on the prematurity and low birth
weight (Cocchi, 2004) in Downs, I have decided to cross the data, to look for a
possible linkage between low birth weight, as the cause of an internal
metabolic stress, and laxity / hypotonia in this population.
The starting point of this new research, is
always in the same consecutive series of 510 Down, selected with the exclusion
of autistic subjects or with other Pervasive Developmental Disorders.
Materials and methods.
This investigation used my clinical cards
referring to a consecutive series of home reared and home living Italian Downs
as seen in outpatients' clinic by myself since 1979 to 1993. Psychotic subjects'
cards were excluded.
During their 1st consultation I recorded the
birth weight as I checked on discharge cards of the obstetrics department or as
the parents told me. During the first consultation I noted the presence of the
absence of joint laxity / hypotonia.
From all cards I collected:
- the gender;
- the chromosomal diagnosis;
- the age at 1st consultation;
- the birth weight;
- joint laxity and/or muscle hypotonia
(termed also, laxity / hypotonia).
I statistically processed data by gender, chromosomal
diagnoses, birth weight, laxity / hypotonia. I applied Chi Square Test, when
suitable.
Results.
I summarized the results in the charts 1-6.
Tab 1: Epidemiological data
of the whole series.
|
|
No. of Ss |
% |
|
|
510 |
100.00 |
|
Males |
292 |
57.25 |
|
Females |
218 |
42.57 |
|
M/F ratio |
133.94 |
|
|
|
|
|
|
Chromosomal diagnoses |
|
|
|
Standard trisomy 21 |
461 |
90.39 |
|
Mosaicisms |
16 |
3.14 |
|
Translocations |
16 |
3.14 |
|
Unknown, only clinical diagnosis |
17 |
3.33 |
|
|
|
|
|
Age at 1st consultation (months) |
|
|
|
Range |
6-510 |
|
|
Average +/- SD |
71.37 +/- 69.71 |
|
As we may see in the table 1, the M/F ratio
appears poorly different (133 vs 135) from what we know for Italian newborn and
alive Down children (Camera and Mastroiacovo,1984). Even the distribution of
the chromosomal diagnosis, meets the ranges of variability for Italian and
international samples (Camera e Mastroiacovo,1984; Hook, 1983; Hook, Cross and
Schreinemachers, 1983).
For these reasons, we may think the sample
here investigated as representative of at least the Italian population of
Downs.
Tab. 2: Distribution of the prevalence of
the symptom "laxity /hypotonia" as for genede, chromosomal diagnoses,
and age at first consultation.
|
|
Ss no. |
% |
|
The whole sample |
510 |
100.00 |
|
Not investigated |
9 |
1.76 |
|
Symptom presence |
142 |
27.84 |
|
|
||
|
Symptom presence |
142 |
100.00 |
|
Males |
79 |
55.63 |
|
Females |
63 |
44.37 |
|
M/F ratio |
125.40 |
|
|
|
||
|
Chromosomal diagnosis |
|
|
|
Standard trisomy 21 |
130 |
91.55 |
|
Translocations |
6 |
4.22 |
|
Mosaicisms |
4 |
2.82 |
|
Only clinical diagnosis |
2 |
1.41 |
|
|
||
|
Age at first consultation |
|
|
|
Average +/- SD (months) |
35.98 +/- 35.33 |
|
|
Range (months) |
6-164 |
|
Tab. 3: Epidemiological data of the
subsample (56 Ss) with low birth weight.
|
Birth weight (grams) |
No. of Ss |
% |
|
<1500 |
1 |
0.20 |
|
>1499 e <2000 |
9 |
1.76 |
|
>1999 e <2500 |
46 |
9.02 |
|
Total of Ss with low birth weight |
56 |
10.98 |
|
|
|
|
|
Normal birth weight |
361 |
78.78 |
|
Not recorded |
93 |
18.24 |
|
Total |
510 |
100.00 |
How we may see in the table 3, the low birth
weight counts for 10.09% of the whole series. How it happened for the
gestational age at birth, even here, in the first three years when I faced Down
syndrome Ss, I did not record this parameter, and I could not integrate it
later.
Tab 4: Distribution of the low birth weight
with regard to the presence or to the absence of laxity / hypotonia (56 Ss).
|
|
Females |
Males |
|||
|
|
With laxity / hipotonia |
With laxity / hipotonia |
|||
|
|
No. of Ss |
% |
No. of Ss |
% |
|
|
Low birth weight |
8 |
14.29 |
15 |
26.79 |
|
|
M/F ratio |
187.5 |
||||
|
|
|
|
|
|
|
|
|
Without laxity / hipotonia |
Without laxity / hipotonia |
|||
|
Low birth weight |
9 |
16.07 |
24 |
42.86 |
|
|
M/F ratio |
266.67 |
||||
|
|
|
||||
|
Totals |
17 |
30.36 |
39 |
69.64 |
|
Chi Square = 0.094 with 1
df and p = 0.760 NS
I did not find any statistically meaningful
prevalence as for the gender.
Tab. 5: Distribution of the chromosomal
diagnoses in low birth weight Ss, with or without laxity / hypotonia.
|
|
With laxity / hipotonia |
Without laxity / hipotonia |
Totals |
|||||
|
Chromosomal diagnosis |
No. of Ss |
% |
No. of Ss |
% |
No. of Ss |
% |
||
|
|
|
|||||||
|
Standard trisomy 21 |
21 |
91.30 |
28 |
84.85 |
49 |
87.5 |
||
|
Mosaicisms |
0 |
|
1 |
3.03 |
1 |
1.79 |
||
|
Translocaztons |
2 |
8.70 |
2 |
6.96 |
4 |
7.14 |
||
|
Only clinical diagnosi |
0 |
|
2 |
6.06 |
2 |
3.57 |
||
Chi Square (with 0 = 0.01
for computation) = 2.234 with 3 df and p = 0.718 NS.
The distribution of the chromosomal diagnosis
doesn't differ in a statistically meaningful way between the two subsamples of
Ss with low birth weight.
Tab. 6: Presence or absence of laxity /
hypotonia as for the birth weight (417 Ss with both data recorded out of 510
Ss).
|
|
With laxity / hipotonia |
Without laxity / hipotonia |
||
|
|
No. of Ss |
% |
No. of Ss |
% |
|
With low birth weight |
23 |
5.52 |
33 |
7.91 |
|
With normal birth weight |
98 |
23.50 |
263 |
63.07 |
If we needed a further confirmation of the lack
of linkage between low birth weight and laxity / hypotonia, this comes out from
the presence of 23.50% of it with normal birth weight, against 5.52% of laxity
/ hypotonia in low birth weigh Ss.
Discussion.
Even on this new research I can write only
fewer words. This is the first one on this topic, at least for what I found on
Google, and on Medline since 1960. This appears much curious because the Down
syndrome has very much literature. Evidently even this, as that of the
relationship between prematurity and laxity / hypotonia (Cocchi, 2004 ) was a
matter of poor interest. The results here obtained, point that low birth weight
and the laxity / hypotonia, about surely are two independent events in the Down
syndrome.
References.
Camera G., Mastroiacovo P.: Epidemiologia della sindrome di Down. In. Ce.Pi.M.
(ed): Aspetti epidemiologici, genetici, clinici, riabilitativi e sociali della
sindrome di Down.
Ce.Pi.M., Genova 1984: 225-230
Cocchi R. Ligamentous laxity and hypotonicity in Downs. An epidemiological
investigation on 510 subjects. 2003
<www.stress-cocchi.net/Downs34.htm>
Cocchi R. Which relationship between tongue protrusion and
joint laxity / hypotonia in Downs? An epidemiological investigation on 452
subjects.
2004 <www.stress-cocchi.net/Downs43.htm>
Cocchi R. Prematurity and low birth weight in Downs. an
epidemiological investigation on 510 subjects. July 2004,
<www.stress-cocchi.net/Downs44.htm>
Cocchi R. Gestational age at delivery and laxity /
hypotonia in Downs: Is there a link? An epidemiological extension of two separate
investigations on a series of 510 subjects. <www.stress-cocchi.net/Downs45.htm>
Hook, E. G. Epidemiology of Down syndrome.
In, Pueschel, S. M. and Rynders, J. E. (eds.): Down
Syndrome. Advances in Biomedicine and the Behavioral Sciences.
Cambridge: Ware Press,1983.
Hook, E. B.; Cross, P. K. and Schreinemachers, D. M. Chromosomal
abnormality rates at amniocentesis and in live-born infants.
J.A.M.A. 1983, 249: 2034-2038,
Posted
on Internet on 26 July 2004. Copyright by R. Cocchi, 2004.
Author's address: Dr Renato COCCHI, via
Rabbeno, 3
42100 Reggio Emilia (Italy)
renatococchi@libero.it
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