Deficits in Long-Term Recognition Memory Reveal Dissociated Subtypes in Congenital Prosopagnosia

The study investigates long-term recognition memory in congenital prosopagnosia (CP), a lifelong impairment in face identification that is present from birth. Previous investigations of processing deficits in CP have mostly relied on short-term recognition tests to estimate the scope and severity of individual deficits. We firstly report on a controlled test of long-term (one year) recognition memory for faces and objects conducted with a large group of participants with CP. Long-term recognition memory is significantly impaired in eight CP participants (CPs). In all but one case, this deficit was selective to faces and didn't extend to intra-class recognition of object stimuli. In a test of famous face recognition, long-term recognition deficits were less pronounced, even after accounting for differences in media consumption between controls and CPs. Secondly, we combined test results on long-term and short-term recognition of faces and objects, and found a large heterogeneity in severity and scope of individual deficits. Analysis of the observed heterogeneity revealed a dissociation of CP into subtypes with a homogeneous phenotypical profile. Thirdly, we found that among CPs self-assessment of real-life difficulties, based on a standardized questionnaire, and experimentally assessed face recognition deficits are strongly correlated. Our results demonstrate that controlled tests of long-term recognition memory are needed to fully assess face recognition deficits in CP. Based on controlled and comprehensive experimental testing, CP can be dissociated into subtypes with a homogeneous phenotypical profile. The CP subtypes identified align with those found in prosopagnosia caused by cortical lesions; they can be interpreted with respect to a hierarchical neural system for face perception

Prosopagnosie (syn. Gesichtsblindheit) – Berichte von Betroffenen

Menschen mit Prosopagnosie, syn. Gesichtsblindheit, können Andere am Gesicht allein nicht wiedererkennen. In spontan zugesandten Berichten von Betroffenen wird aus sehr unterschiedlichen Perspektiven die Problematik im Alltag geschildert. Sie dokumentieren die Vielfalt aber vor allem auch die große Übereinstimmungen der Symptomatik. Das Entwickeln von zahlreichen kompensatorischen Strategien, die vielen typischen Anekdoten, sowie das häufige Fehlen von inneren Bildern beschreiben übereinstimmend das subjektive Empfinden einer Prosopagnosie

Acquired and hereditary prosopagnosia in history, fiction literature, biographies, and live celebrities of the present

Prosopagnosia (syn. face blindness) describes an inborn or acquired deficiency of face perception. In probands with this anomaly the ability to recognize even familiar faces is impaired, whereas faces expressing emotions, attractiveness and gender are clearly seen. In contrast to the acquired form, which is easily diagnosed by the sudden loss of a skill, the congenital form is mostly overlooked. Nevertheless, prosopagnosia is very common and almost always hereditary. Once alerted to this phenomenon it is found by chance – sometimes hidden - in a variety of sources as in autobiographies, poems, celebrities in live radio/TV programmes, and even one’s own close friends. Almost all of the subjects think their problem is unique, and in cases with the very frequent hereditary form, nearly all of the affected individuals were not aware of other impaired first-degree relatives

Hereditary prosopagnosia in self reports

People who suffer from prosopagnosia, syn. face blindness are unable to recognize others solely by their face. Reports by those affected picture the problematic nature from very different perspectives in every day life. Not only the variety, but most notably the wide resemblance of the symptoms is documented. The generation of numerous compensatory strategies, the many typical anecdotes, and the frequent deficiency of inner images concordantly describe the subjective sensibility of prosopagnosia

An intronic COL1A1 Sp1-Polymorphism but not Vitamin D Receptor Gene Polymorphisms Relates to the Phenotypic Expression of Osteogenesis imperfecta

This is the first observation of a polymorphism associated with the severity of clinical manifestation in Osteogenesis imperfecta (OI). The results are consistent with a polygenic quantitative trait model in which OI albeit a monogenic autosomal dominant disease can be modified by additional risk factors. In our collection the severe cases of OI are significantly associated with a COL1A1 Sp1 polymorphism, an association initially observed in postmenopausal women with osteoporosis. In both studies a G → T polymorphism in the same Sp1 motif is found rather in the clinically severe cases. As diverse vitamin D receptor (VDR)-polymorphisms are one of the strongest risk factors of osteoporosis this prompted us to examine a putative association in our OI collection. However, we could not find a correlation of the severity of OI with any of the four polymorphisms (BsmI, ApaI, and TaqI RFLPs). We conclude that the COL1A1 Sp1 polymorphism is of high prognostic value in OI individuals homozygous for the T allele

Extreme founder effect associated with oculocutaneous albinism type 1 (OCA1) on the island of Nias/Indonesia:How clinical genetics may help population genetics

The island of Nias/Indonesia shows an extremely reduced genetic diversity indicating a strong founder effect. One such disorder that can easily be ascertained during field research is albinism. All over the island, probands with albino phenotype were screened for OCA mutations. A novel homozygous tyrosinase mutation c.701C>T was identified in all four probands studied from very distinct parts of the island. The observed prevalence was 1 in 3,260. We argue that clinical genetics and mutation mapping can add to the combined power of population genetics, linguistics, and archeology for subsequent studies on the origin and migration of a given population. In our example mutation testing for tyrosinase exchange c.701C>T in probands outside Nias might be helpful in tracing the potential homelands of the Niassians. So far, candidate regions highly suggestive by population genetic and by comparative linguistic studies are Sangir Islands, Philippines and Taiwan

Klinik des 5p-minus Syndroms (syn. Cri-du-Chat Syndrom):Daten einer Fragebogenerhebung (2010 – 2019)

Eine Fragebogenaktion zur Klinik des 5p-minus Syndroms zeigt, dass die mittlere Schwangerschaftsdauer, das Geburtsgewicht und die Geburtslänge meist im Normbereich liegen. Zum Zeitpunkt der Geburt ist nur der Kopfumfang im unteren Normbereich und weist auf eine spätere Mikrozephalie hin. Die kritische Phase einer erhöhten Sterblichkeit ist nach 3 Monaten (max. 1 Jahr) überwunden. Die Entwicklung im Säuglingsalter ist zwei bis dreifach verzögert mit sehr großen zeitlichen Spannen. Am stärksten betroffen sind die Sprachentwicklung, sowie die Grob- und entsprechend die Fein-Motorik. Im 1. Lebensjahr bestehen ausgeprägte Fütterungsprobleme, Gedeihprobleme und Infektionen (u.a. Mittelohrentzündungen). Im weiteren Verlauf stehen weiterhin massives Erbrechen, Darmverstopfung und Schlafstörungen im Vordergrund; hinzukommen orthopädische Probleme wie Fußfehlstellungen und Skoliose. Ein großes Problem für die Sozialisierung sind die ausgeprägten Schwierigkeiten bei der (Laut-)Sprachentwicklung

Prevalence of hereditary prosopagnosia – a worldwide survey

Prosopagnosia, or face blindness, is a term designating the inability to recognize people by their face only. Until 2001, the few cases reported in the literature were almost all of the acquired form and the inborn form, with less than 20 case reports, was thought to be even rarer. In 2006, we showed that hereditary (syn. congenital) prosopagnosia belongs to one of the most common cognitive dysfunctions with a prevalence rate of 2.49 % in the German Caucasian population. Following previous work, we extended the study to 17 populations from 13 countries on four continents. The observed overall prevalence rate of 0.93% (range 0.26% - 2.47%) of the populations studied worldwide is in the same order of magnitude. This is a minimal estimate, as only 41% of the subjects who were highly suspected of prosopagnosia allowed for a follow-up examination. Extrapolating this frequency to a complete coverage, the expected prevalence rate is 2.29%. Whenever we had access to family history, we found at least one first degree relative with prosopagnosia showing that this cognitive dysfunction is highly hereditary