A new study to be published in Schizophrenia Research[1] has found that markings on the hand may be a sensitive marker for genetic and environmental factors in schizophrenia.

Anthropologists in Barcelona, Spain studied the hand patterns of patients with schizophrenia, their relatives and healthy 'control' subjects. They looked at A-B ridge count, which is the number of ridges between two points on the palm called A and B (defined by specific areas where patterns converge under the second and third digits). There was no overall difference in A-B ridge count, but A-B ridge count was lower (fewer ridges) in schizophrenic patients with a low birth weight, and also in patients who did not have a family history of schizophrenia.

According to the study, the frequency of ectodermic derivates abnormalities (that is, Ridge Dissociation [RD] and/or Abnormal Palmar Flexion Creases [APFC] - abnormalities originating from the embryonic ectodermal layer of tissue, including the epidermis) appeared to be higher in patients and relatives than in controls. Ridge dissociation refers to short broken segments of lines that cover the patterns of dermatoglyphic areas in a disorganized way. Examples of abnormal palmar flexion creases are the Simian line, the Sydney line, clear broken proximal and distal palmar creases, and very rudimentary creases. Associations of this kind studying RD and APFC have been found in previous studies, one of them[2] concluding that factors affecting early foetal development may increase the risk for psychotic disorder. In this new study males had more of these abnormalities than females, which also shows the potential influence of male hormones in response to stress. Males also had more fluctuating asymmetry of their A-B ridge count (difference between left and right hands).

Overall these studies show the importance of maintaining a peaceful and stress-free environment for the unborn child, as well as highlighting a potentially observable risk factor for schizophrenia.

References:
1: Fatjó-Vilas M, Gourion D, Campanera S, et. al.
"New evidences of gene and environment interactions affecting prenatal neurodevelopment in schizophrenia-spectrum disorders: A family dermatoglyphic study."
Schizophr Res. 2008 Jun 24.
PMID: 18583099

2: Rosa A, Fañanas L, Bracha HS, Torrey EF, van Os J.
Am J Psychiatry. 2000 Sep;157(9):1511-3.
Congenital dermatoglyphic malformations and psychosis: a twin study.
PMID: 10964873

Follow up:

Full abstract follows:
1: Fatjó-Vilas M, Gourion D, Campanera S, et. al.
"New evidences of gene and environment interactions affecting prenatal neurodevelopment in schizophrenia-spectrum disorders: A family dermatoglyphic study."
Schizophr Res. 2008 Jun 24.
Abstract
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 (FA(ABRC)), 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 FA(ABRC) 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.
PMID: 18583099