c Indian Academy of Sciences
RESEARCH NOTE
Alpha-1 antitrypsin phenotypes in patients with Klinefelter’s syndrome
RUTH MIKELSAAR1∗ , JELENA LISSITSINA1 , KRISTO AUSMEES2 , MARGUS PUNAB2 ,
PAUL KORROVITS2 and EVE VAIDLA1
1
Department of Human Biology and Genetics, Institute of General and Molecular Pathology,
University of Tartu, Ravila Street 19, Tartu 50411, Estonia
2
Centre of Andrology, Tartu University Hospital, Puusepa Street 1a, Tartu 50406, Estonia
Introduction
Klinefelter’s syndrome (KS) is the most common human sex
chromosome disorder, with a prevalence of 1 in 660 men.
The phenotype is variable, but the most constant findings are
small and firm testes, decreased testosterone level, infertility,
eunuchoid body proportion, increased height, and learning
disabilities, due to the presence of extra X chromosome(s)
(Smyth and Bremner 1998). KS patients have frequently
other diseases of lung, skin, liver and kidney (Morales et al.
1992; Swerdlow et al. 2005). Restrictive lung defects have
been attributed to chest wall abnormalities, decreased respiratory muscle strength and increased chest wall compliance
(Huseby and Petersen 1981). The likely cause is, decrease
of lung compliance due to diminished elasticity of the lung
matrix, but its biochemical cause is unknown (Morales et al.
1992).
One of the causes could be the mutations in the alpha-1
antitrypsin (AAT) gene (SERPINE1), which is highly polymorphic, with more than 100 alleles identified so far. The alleles are categorized into normal, deficient and null variants
on the basis of the plasma level and function of AAT. The
protein phenotype is classified according to the ‘Pi’ (protease
inhibitor) system, as defined by plasma isoelectric focusing.
Normal Pi M types account for 95% of alleles in Caucasian
individuals and are characterized by normal plasma levels.
Pi X is a rare normal allele variant. Pi Z, S and null types
are the most frequent AAT deficiency variants described in
lung pathology, but Pi ZZ is associated with both pulmonary
and liver diseases (Kaczor et al. 2007; Greene et al. 2008).
AAT gene is located on chromosome 14q32.1 (Schroeder et
al. 1985).
*For correspondence. E-mail: [email protected].
[Mikelsaar R., Lissitsina J., Ausmees K., Punab M., Korrovits P. and Vaidla
E. 2010 Alpha-1 antitrypsin phenotypes in patients with Klinefelter’s syndrome. J. Genet. 89, 485–488]
AAT gene codes alpha-1 antitrypsin, a 52-kDa plasma
protein, which is a type of serine protease inhibitor (serpin)
produced mainly by the liver. Its main physiological roles
are to inhibit neutrophil elastase and contribute to the innate immune system as an anti-inflammatory protein. Reduced or abnormal production in the body of the AAT protein
causes alpha-1 antitrypsin deficiency. It is a genetic disorder
characterized by low serum level of AAT, and affects about
1 in 3000 of the population in northern Europeans (WHO
1997). AAT deficiency predisposes individuals to develop severe diseases of lung, liver and other organs. There is only
one study about the AAT deficiency in KS in the literature
(Varkey and Funahashi 1982).
In the present study, we attempt to evaluate whether alterations of AAT contribute to risk of lung defects and other
diseases observed in KS patients. We, therefore, studied AAT
phenotypes and serum level in 13 KS patients. This is the
second study and an attempt to shine light on the association
between AAT deficiency and other diseases in KS patients.
Materials and methods
Thirteen KS patients were selected from infertile males referred to cytogenetic analyses by andrologists (Lissitsina et
al. 2006). Their mean age was 35.5 years (range 21–67
years). All participants gave their signed informed consent
prior to their inclusion in the study.
The patients filled in a questionnaire and medical histories were recorded. In specification of diagnoses, diseases
were coded using the International Classification of Diseases
(ICD-10), which showed codes for pneumonia J18, bronchitis J20, allergy J30.1, blood pressure I10, skin diseases
(atopic dermatitis L20.9 and leg ulcer L97) and kidney problem N10. History of smoking was classified into: nonsmoker
(individual who never smoked before or had quit for more
than a year); smoker (anyone who was currently smoking at
least 10 cigarettes a day).
Keywords. alpha-1 antitrypsin; alpha-1 antitrypsin deficiency; Klinefelter’s syndrome; leg ulcer; lung disease.
Journal of Genetics, Vol. 89, No. 4, December 2010
485
Ruth Mikelsaar et al.
Semen analyses were assessed in two samples according to the criteria of World Health Organization but slightly
modified (Andersen et al. 2000). Cytogenetic analyses were
carried out on metaphase spreads from peripheral blood lymphocyte culture using GTG band method (Seabright 1971).
The AAT level in serum was determined by latex-enhanced
immunoturbidimetric assay (reference value was 0.9–2.0
g/L). The AAT phenotype was defined by isoelectric focusing on ultra thin (0.25 mm) agarose gel layer (pH range 4.2–
4.9) (Qureshi and Punnett 1982). The AAT phenotype data of
a random population sample of similar genetic background
(n = 1422) were used as controls (Uibo et al. 1991).
Results
All 13 patients were azoospermics with karyotype 47,XXY
and had one or more specific diseases. Of the 13 patients nine
individuals (69%) suffered from some kind of respiratory disease (table 1), of whom four had a history of both recurrent
pneumonia and bronchitis (pt no. 1, 5, 9, 10), three had pneumonia (pt no. 2, 3, 8) and two had recurrent bronchitis (pt no.
7, 12) in their medical history. Three individuals had allergic
rhinitis and another two suffered from skin diseases such as
atopic dermatitis or infected leg ulcers. Ten men were daily
smokers.
The AAT level of our patients was 0.74–1.48 g/L (controls range 0.9–2.0 g/L) with the mean value of 1.25 g/L
(controls mean value 1.45 g/L). Four individuals (no. 3, 5,
7, 10) had AAT levels lower than the mean value of the patients group (1.25 g/L). From them, one (no 7) had a borderline AAT serum level (1.09 g/L) and suffered from recurrent
bronchitis. Another patient (no. 10) with the AAT level (0.74
g/L) lower than the reference value had both several episodes
of bronchitis/pneumonia and kidney disease.
AAT phenotypes, revealed by isoelectric focusing, were
Pi M types in 11 subjects. Two of them had phenotype with
AAT deficiency. One patient (no. 10) had Pi XZ phenotype.
His mother had the Pi MX phenotype, but his father had died
of liver failure and cirrhosis, and was not available for phenotyping. The second (no. 13) had Pi M1 0 phenotype and AAT
level of 1.44 g/L.
Discussion
Pulmonary disease has been discribed with increased frequency in patients with klinefelter’s syndrome (Huseby and
Petersen 1981). In the present study, although in the small
group of patients (table 1), 69% (9/13) of them had diseases
of the respiratory system, frequency of which is similar to
previously reported in other studies (61%) (Huseby and Petersen 1981; Morales et al. 1992).
The cause of the lung diseases in KS has not yet been
established. Deformities of chest wall, such as kyphoscoliosis and pectus excavatum can cause lung diseases, but none
of our patients with lung problems had the chest wall deformities, as also shown by Morales et al. (1992). Testosterone
deficiency in KS may lead to delayed bony maturation making the thoracic bony structure more compliant, but no direct
proof has been presented to sustain this opinion. The likely
cause of the lung disorders is a diminished elasticity of the
lung matrix, the biochemical events of which are not known.
One of the risk factors of lung diseases and other disorders may be due decreased AAT serum level. The major
function of AAT is to protect the target tissue from destruction neutrophil elastase released from triggered neutrophils.
The lung disease is associated with decreased anti-protease
protection of the airways, and patients may have bronchitis,
pneumonia or nonspecific symptoms such as cough, wheezing and chest infections (Greene et al. 2008).
Table 1. Patients with Klinefelter’s syndrome, serum AAT levels, AAT phenotypes and specific diseases (ICD-10).
Patient
AAT
g/L
AAT
Pi
Smoking
Pneumonia
(J18)
Bronchitis
(J20)
Allergy
(J30.1)
↑ Blood pressure
(I10)
Skin disease
(L20.9; L97)
Kidney disease
(N10)
1
2
3
4
5
6
7
8
9
10
11
12
13
1.39
1.34
1.17
1.29
1.18
1.48
1.09
1.32
1.32
0.74
1.23
1.34
1.44
M1 M3
M1 M 1
M1 M1
M1 M2
M1 M1
M1 M1
M1 M1
M1 M 1
M1 M1
XZ
M1 M 1
M1 M 1
M1 0
+
–
+
–
–
+
+
+
+
+
+
+
+
+
+
+
–
+
–
–
+
+
+
–
–
–
+
–
–
–
+
–
+
–
+
+
–
+
–
+
–
–
–
+
–
–
–
–
–
+
–
–
–
–
–
+
–
+
–
+
–
–
–
–
–
+
–
–
–
–
–
–
–
–
–
–
–
+
–
–
–
–
–
–
–
–
–
+
–
–
–
486
Journal of Genetics, Vol. 89, No. 4, December 2010
Alpha-1 antitrypsin in Klinefelter’s syndrome
There are few data on the circulating AAT level in both
general population and KS patients. In our 13 KS individuals, it was lower (1.25 g/L) than the mean reference AAT
value (1.45 g/L) in the laboratory. Four patients had AAT
level even lower than the mean value of the group. One (no.
10) showed AAT level (0.74 g/L) below the reference value
of 0.9 g/L, that is higher than 3.4% shown by Senn et al.
(2008) in the general population of European–Caucasian ethnicity and Swiss nationality (Senn et al. 2008). These findings support the opinion that the lowered AAT level could
be associated with the higher frequency of different health
problems, including lung diseases in KS patients.
Although there are many reports about the phenotyping
of AAT in general population as well as in individuals with
lung diseases, the same data in the KS patients have been reported previously in only one study (Varkey and Funahashi
1982). In the present study, the most prevalent Pi phenotype
was M1 M1 , but two phenotypes with AAT deficiency alleles
were revealed. Varkey and Funahashi (1982). have described
one patient from nine KS patients with Pi MS phenotype and
a serum AAT level of 100 mg%. Combining data from latter
study with our data, it is noted that three of 22 KS individuals had AAT deficiency, with a frequency of 1:3000 in the
general population.
We have found two KS patients with AAT deficiency.
Case 1 (no. 10) had phenotype XZ and the AAT level of 0.74
g/L and also had repeated bronchitis/pneumonia and kidney problems from childhood. Varkey and Funahashi (1982).
found lung defect in five patients (5/9) of them one had AAT
deficiency (Pi MS phenotype). Combining data of both studies, it is noted that 2/14 KS patients had both lung disease and
AAT deficiency. The Pi X allele is a rare normal AAT variant
(OMIM +107400). Its frequency is approximately 0.0002 in
Europe (WHO 1997). The Pi Z allele is a more common deficiency variant in Europe (frequency of 0.5%–4%) (Luisetti
and Seersholm 2004). Most pathology related to AAT deficiency is linked to the Z allele (Fregonese and Stolk 2008).
Case 2 (no. 13) with infected leg ulcer had the AAT phenotype M1 0. Pi 0 mutations are rare and associated with no
detectable circulating AAT in plasma (Greene et al. 2008).
Our patient’s serum AAT level was not lowered (1.44 g/L)
that could be explained by the leg ulcer and the chronic inflammation.
In Estonia, the most common Pi allele is M1 (0.691) that
was also the most prevalent allele in our group of patients.
The frequencies of Z and S alleles are 0.025 and 0.013, respectively (Uibo et al. 1991). The frequency of other alleles
in Estonia is 0.0073, but the exact frequencies of X and 0
alleles have not been found.
Cigarette smoking can lower AAT serum concentration
and predisposes to lung disease. Although, 10 patients were
smoking at least 10 cigarettes a day, no correlation between
smoking and AAT serum concentrations was found. Most of
the individuals had lung problems from childhood, before
they started smoking.
All KS patients were azoospermics and infertile with
AAT levels in the lower half of the reference value. Our finding coincided with the data, which have shown that azoospermic ejaculates had lower mean AAT concentration compared to oligo-zoospermic and normo-zoospermic ejaculates
(Schill 1976). Handelsman et al. (1986) found reduced semen volume in infertile men with homozygous ZZ AAT deficiency. Investigations of a large family have shown that three
brothers with Pi FZ phenotype had an unusually small number of offsprings when compared to their eight siblings (1
versus 39) (Cockcroft et al. 1981). However, there are also
contradicting data, which showed that AAT level was significantly higher in 14% of infertile men (Uleova-Gallova et al.
1999).
In conclusion, 3 of 24 KS patients (from combined study)
had lowered AAT level and AAT deficiency, especially individuals with lung diseases (2/14). Although, the number of
patients was small and does not allow to draw concrete conclusions, our finding show a possibility that these biochemical events may contribute to risk of additional diseases in KS
patients and need further studies.
Acknowledgements
This study was supported by target financing SF 0188096s08 of Estonian Ministry of Science and Education.
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Received 12 January 2010, in final revised form 6 May 2010; accepted 14 June 2010
Published on the Web: 10 November 2010
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