Dermatoglyphics and abnormal palmar flexion creases as markers of early prenatal stress in children with idiopathic intellectual disability

Kristine Bonnevie's theories on the genetics of fingerprints, and their application in Germany

This paper offers a historical reconstruction of the efforts to geneticize fingerprints, focusing on the theories put forward by the Norwegian biologist Kristine Bonnevie. The criminological and colonial roots of the preoccupation with fingerprints led to the creation of huge catalogues of fingerprints, which later became the starting point of Bonnevie's analysis. Building on insights she gained from her studies on the inheritance of human pathologies, Bonnevie insisted that all ten fingers exhibited varying manifestations of a single, underlying genotypic design. In 1923-4, she identified several theoretical genes that presumably constituted this hypothetical genotypic finger; five years later she revised her theory in light of a series of embryological dissections she conducted. Her new theory was adopted by German jurists, doctors and racial-anthropologists who relied on it to determine legal questions of disputed paternity. The extensive application of Bonnevie's genetic theory also exposed its deficiencies, and by the late 1950s her model was abandoned. At the same time, one of the most important genetic variables that Bonnevie discovered (or, invented) entered mainline genetic theory, and is still being used to this very day. The paper examines these developments, highlighting the multiple and complex relations between scientific theory building, practical considerations related to the gathering and processing of data, and social, racial and gender biases that shaped the process of "Mendelization" of finger print patterns.

Dermatoglyphic fluctuating asymmetry and total a-b ridge count as biomarkers of Foetal Alcohol Syndrome: Analysis in children adopted from Eastern Europe

BACKGROUND

Dermatoglyphics, formed mainly during the second trimester of pregnancy have been used as markers of developmental disturbances. The aim of this study was to examine if dermatoglyphic variation in children adopted from Eastern European countries with differential prenatal alcohol exposure, could be associated with diagnosis of Foetal Alcohol Spectrum Disorder (FASD).

METHODS

Total a-b ridge count (TABRC), total ATD angle (TATD), palpebral fissure asymmetry and fluctuating asymmetry of the a-b ridge count (FA_ABRC) and ATD angle (FA_ATD) were obtained from NO FASD (n = 40) and FASD (n = 145; FAS = 54, pFAS = 64; ARND = 13; ARBD = 14) individuals. NO FASD and FASD subgroups were statistically compared for dermatoglyphic variables. Correlations between dermatoglyphics and FASD diagnosis were also performed.

RESULTS

TABRC showed significantly higher values in foetal alcohol syndrome (FAS, p = 0.006) and partial FAS (pFAS, p = 0.040) groups compared to NO FASD controls. Similar results were obtained for TATD (FAS, p = 0.015 and pFAS, p = 0.032) compared to controls. Significantly higher values in FAS, pFAS and alcohol-related neurodevelopmental disorders (ARND) groups were observed for FA_ABRC (p = 0.034, p = 0.007, p = 0.007 respectively) and for FA_ATD in FAS group (p = 0.014) compared to NO FASD. Additionally, FAS group with mean + 2SD in palpebral fissure asymmetry showed statistical significance compared to NO FASD (p = 0.018). Dermatoglyphic variables also correlated (rho, Spearman) significantly with FASD diagnosis.

CONCLUSION

Dermatoglyphic pattern and FASD are related. The validation of dermatoglyphics as an associated marker with FASD together with the currently diagnostic tools would help clinicians to an early FASD diagnosis in children.

Individuals with nonsyndromic orofacial clefts have increased asymmetry of fingerprint patterns

Dermatoglyphic patterns on the fingers often differ in syndromes and other conditions with a developmental component, compared to the general population. Previous literature on the relationship between orofacial clefts–the most common craniofacial birth defect in humans–and dermatoglyphics is inconsistent, with some studies reporting altered pattern frequencies and/or increased asymmetry and others failing to find differences. To investigate dermatoglyphics in orofacial clefting, we obtained dermatoglyphic patterns in a large multiethnic cohort of orofacial cleft cases (N = 367), their unaffected family members (N = 836), and controls (N = 299). We categorized fingerprint pattern types from males and females who participated at five sites of the Pittsburgh Orofacial Cleft study (Hungary, United States of America (Pennsylvania, Texas), Spain, and Argentina). We also calculated a pattern dissimilarity score for each individual as a measure of left-right asymmetry. We tested for group differences in the number of arches, ulnar and radial loops, and whorls on each individual’s hands, and in the pattern dissimilarity scores using ANOVA. After taking sex and site differences into account, we did not find any significant pattern count differences between cleft and non-cleft individuals. Notably, we did observe increased pattern dissimilarity in individuals with clefts, compared to both their unaffected relatives and controls. Increased dermatoglyphic pattern dissimilarity in individuals with nonsyndromic orofacial clefts may reflect a generalized developmental instability.

Functional Asymmetry and Fingerprint Features of Left-Handed and Right-Handed Young Yakuts (Mongoloid Race, North-Eastern Siberia)

An ethnically homogeneous group of Yakuts (Mongoloid race, Northeast Asia), aged 18–31, was studied to characterize the diversity of particular features between left- and right-handed individuals. A total of 52 left-handed (32 women and 20 men) and 100 right-handed (50 women and 50 men) individuals were studied. Testing included two sets of questions and tasks, dynamometry of the right and left hand, and fingerprint analysis. Left-handed and right-handed people were found to differ in functional asymmetry of psychophysiological and motor reactions. Right-handers were characterized by higher intragroup similarity, while, among left-handers, greater dispersion of these traits was observed. Asymmetry in hand grip strength was less pronounced in the left-handed people than in the right-handed; this difference was statistically significant, and the difference was greater in men than in women. This suggests that the non-dominant hand in the left-handed people was subjected to a greater load and indicates the forced adaptation of the left-handed people to “dextrastress”. No significant difference between sexes was found when analyzing fingerprint patterns. Left-handers had arches significantly more often than right-handers. Radial loops were most often found on the index finger, and, in the left-handers, their occurrence was significantly higher on three to five fingers of the left hand compared with the right-handers. The levels of fluctuating asymmetry in left-handers and right-handers were similar.

Dermatoglyphics in children prenatally exposed to alcohol: Fluctuating asymmetry (FA) as a biomarker of alcohol exposure

BACKGROUND

Dermatoglyphics alterations have been demonstrated to be an effective complement in the diagnosis of developmental disorders and a marker of prenatal stress. Several genetic and environmental factors can modify their morphology. Once defined, dermatoglyphics remain constant throughout life, being considered fossilized markers of the intrauterine development. Variations in bilateral morphological traits within an individual reflect developmental disturbances and can be measured by fluctuating asymmetry. The aim of this study was to evaluate if dermatoglyphic variations can be used as a surrogate marker prenatal alcohol exposure (PAE) during foetal development. Dermatoglyphics from 58 individuals who were either exposed or non-exposed to alcohol during pregnancy (according to the levels of Fatty Acid Ethyl Ethers (FAEE) found in meconium at birth) were analyzed.

METHODS

Total a-b ridge count (TABRC) and levels of fluctuating asymmetry from the a-b ridge count (FA_ABRC) were obtained.

RESULTS

A significant correlation between FA and FAEE levels was found in prenatally alcohol exposed individuals (r = 0.64, p = 0.0032). Remarkably, samples with highest values of FAEEs showed greater FA_ABRC (6.33 ± 4.18) levels than the values of non-exposed to alcohol (2.87 ± 1.74) as well as the exposed at low concentrations (2.6 ± 1.43) (U = 61, p = 0.05 and U = 14.5, p = 0.05, respectively).

CONCLUSION

Heavy prenatal ethanol exposure (demonstrated by high levels of FAEEs) alters the neuroectoderm developmental program during pregnancy: PAE correlates with FA_ABRC, which behaves as a dermatoglyphic variable sensitive to FASD and deserves to be studied as a surrogate marker of neurodevelopmental damage during foetal development.

Mild dermatoglyphic deviations in adolescents with autism spectrum disorders and average intellectual abilities as compared to typically developing boys

Dermatoglyphics, ridge constellations on the hands and feet, are permanently formed by the second trimester of pregnancy. Consequently, they are considered “fossilized” evidence of a specific prenatal period. A high frequency of dermatoglyphic anomalies, or a high rate of dermatoglyphic asymmetry (discordance), is an indication of developmental instability (prenatal disturbances) prior to 24-week gestation. Most dermatoglyphic studies in psychiatry focus on adult schizophrenia. Studies on dermatoglyphic deviances and autism are sparse, include severely disturbed and intellectually retarded patients with autism, and are carried out mainly in non-Western European populations. In this study, finger print patterns, atd-angles, and palmar flexion crease patterns (PFCs) are compared between Western European adolescent teenage males, of average intellect, with Autism Spectrum Disorders (ASD; n = 46) and typically developing adolescent teenage males (TD; n = 49). Boys with ASD had a higher rate of discordance in their finger print patterns than TD boys. Thus, the hypothesized prenatal disturbances that play a role in the etiology of schizophrenia and severe autism might not be specific to these severe psychiatric disorders but might also be involved in the etiology of varying degrees of ASD.

Ectodermal markers of early developmental impairment in very preterm individuals

Individuals born very preterm (before 33 weeks' gestation; VPT) are at risk of life-long, neurological impairments, behavioural and other health problems. It is not clear whether these neurodevelomental abnormalities originate prenatally, postnatally or a combination of both. Dermatoglyphics are stable ectodermal markers of neurodevelopmental disruption in the early prenatal period, as it has previously been reported in neuropsychiatric disorders such as schizophrenia or bipolar disorder. We have analyzed the dermatoglyphic variable total a-b ridge count (TABRC), which is a sensitive marker of ectodermal disruption during the first 24 weeks of foetal development, in 142 very preterm (VPT) individuals and 64 term born young adults. The VPT group showed significantly lower TABRC than the term group, especially those individuals presenting very low birth weight (VLBW), considered a proxy for more extreme prenatal stress, as shown by a two-way Anova analysis. These individuals, at risk of brain abnormalities and behavioural impairments, may have undergone disturbances before preterm birth occurs and prior to the 24th week of gestation. Our results support that dermatoglyphics represent a suitable marker to detect ectodermal alterations which have occurred very early in the course of development, and point out the vulnerability of the immature brain during the first half of gestation which may have adverse health consequences later in life.

New evidences of gene and environment interactions affecting prenatal neurodevelopment in schizophrenia-spectrum disorders: a family dermatoglyphic study

BACKGROUND

Several studies have reported an increase of dermatoglyphic anomalies in schizophrenic patients compared to controls. However, the recognition of specific dermatoglyphic variables related to this disorder and their genetic and/or environmental component are still controversial.

METHOD

We conducted a dermatoglyphic analysis in a new sample of 617 individuals: 205 patients with schizophrenia-spectrum disorders, 224 healthy first degree relatives and 188 healthy controls. The dermatoglyphic variables studied were: the total a-b ridge count (TABRC) and its fluctuating asymmetry (FAABRC), and the presence of ridge dissociations (RD) and abnormal palmar flexion creases (APFC).

RESULTS

Patients, relatives and controls did not differ in TABRC. However, within the patients group those with a low birth weight or absence of psychiatric family history showed lower TABRC than the others. The frequency of ectodermic derivates abnormalities (RD and/or APFC) appeared to be higher in patients and relatives than in controls, while first degree relatives did not differ from patients. Males showed an increased rate of ectodermic derivates abnormalities compared to females in all groups and male patients also presented higher FAABRC than female patients.

CONCLUSIONS

Our results suggest a different relative weight of genetic and environmental factors on each dermatoglyphic variable analyzed: i) TABRC may be a sensitive marker to environmental factors in schizophrenia, ii) ectodermal derivates abnormalities appear to be influenced by genetic risk factors, which could be involved both in the disrupted development of ectodermic derivates like dermatoglyphics and central nervous system and in the vulnerability for schizophrenia.

Dermatoglyphic anomalies and neurocognitive deficits in sibling pairs discordant for schizophrenia spectrum disorders

The neurodevelopmental hypothesis of schizophrenia suggests that adverse genetic loading in conjunction with environmental factors early in fetal life causes a disruption of neural development, decades before the symptomatic manifestation of the disease. Neurocognitive deficits have been observed early on the course of schizophrenia, and their association with an early developmental brain lesion has been postulated. Dermatoglyphics have been analyzed in schizophrenia as markers of prenatal brain injury because of their early fetal ontogenesis and susceptibility to the same environmental factors that can also affect cerebral development. The aim of our study was to conduct a comparative examination of neurocognitive functions and dermatoglyphic variables in 89 sibling pairs discordant for schizophrenia spectrum disorders. Therefore, we investigated the association between these two markers to explore the prenatal origin of cognitive deficits in schizophrenia. The affected siblings were significantly impaired on all the cognitive variables assessed (Wisconsin Card Sorting Test, Trail Making Test and Continuous Performance Test) and had a greater number of dermatoglyphic anomalies. These results suggest the influence of intrauterine environmental factors in the siblings affected with schizophrenia. However, we did not detect a significant association between these two vulnerability markers in the schizophrenic patients, suggesting the role of genetic or late environmental factors in the origin of the neurocognitive deficits found in these patients.

Dermatoglyphic profile in 22q deletion syndrome

A genetic subtype of schizophrenia has been described in 22q11 Deletion syndrome. Previous studies have described an excess of dermatoglyphic alterations in schizophrenia, such as low a-b ridge counts (ABRCs), a high frequency of ridge dissociations, and increased dermatoglyphic fluctuating asymmetry. Little is known however, about the dermatoglyphic profile of 22qDS subjects showing psychotic symptoms and its similarity to the previously reported anomalies in schizophrenia. We studied the palmar dermatoglyphics of 22 subjects with 22qDS of predominantly Caucasian origin, 15 of whom had psychotic illness, and in 84 healthy controls of similar ethnicity. We observed higher values for total ATD angle in cases than in controls (P = 0.04). In addition, there was an excess of radial figures in the hypothenar area in cases, especially in the left hand. Interestingly, greater fluctuating asymmetry, determined by the absolute difference between right and left ABRC, was observed in 22qDS subjects compared to controls (P = 0.05). However, no differences were found for ABRCs and frequency of dissociations. Despite the small sample size, the palmprints analyzed suggest the existence of an altered dermatoglyphic profile in 22qDS, involving: (i) ATD angle amplitude, (ii) presence of radial loops in the hypothenar area, and (iii) an increment of fluctuating asymmetry. The first two features are similar to those found in other genetic syndromes associated with low IQ, while high levels of fluctuating asymmetry have often been reported in schizophrenia.

Learning disability

Learning disability is common, affecting 1-2.5% of the general population in the Western world, and encompasses many different conditions. It usually leads to major functional impairment and lifelong need for support and interventions, not the least important of which are medical and health-care services. Rapid progress is being made in the understanding of the cause and pathogenesis of many learning disability syndromes, and these advances are likely to improve targeted interventions in the next decade. Many countries have abolished a learning disability specialty for medical professionals, but there is a great need to revive this niche of medical knowledge. We know little about quality of life and effects on families of people with learning disability, and research is needed to address these issues.