The prevalence of attention-deficit/hyperactivity disorder among persons with albinism

Oculocutaneous albinism: the neurological, behavioral, and neuro-ophthalmological perspective

Oculocutaneous albinism (OCA) is a group of rare, genetic disorders caused by absent/reduced melanin biosynthesis. The aim of this study was to explore the neurovisual, cognitive, adaptive, and behavioral profile of children affected by OCA, also evaluating any possible effect of the visual acuity deficit on the clinical profile and genotype-phenotype correlations. Eighteen children (9 males, mean age 84 months ± 41; range 18-181 months) with a molecular confirmed diagnosis of OCA were enrolled in the study. We collected data on clinical history, neurodevelopmental profile, neurological and neurovisual examination, and cognitive, adaptive, and emotional/behavioral functioning. A global neurodevelopmental impairment was detected in 56% of the children, without evolving into an intellectual disability. All the patients showed signs and symptoms of visual impairment. Low adaptive functioning was observed in 3 cases (17%). A risk for internalizing behavioral problems was documented in 6 cases (33%), for externalizing problems in 2 (11%), and for both in 5 (28%). Twelve children (67%) showed one or more autistic-like features. Correlation analyses revealed significant associations between the visual acuity level and performance intelligence quotient (p = 0.001), processing speed index (p = 0.021), Vineland total score (p = 0.020), Vineland communication (p = 0.020), and socialization (p = 0.037) domains. No significant correlations were found between genotype and phenotype.

CONCLUSION

Children with OCA may present a global neurodevelopmental delay that seems to improve with age and emotional/behavioral difficulties, along with the well-known visual impairment. An early neuropsychiatric evaluation and habilitative training are recommended to improve vision-related performance, neurodevelopment, and any psychological difficulties.

WHAT IS KNOWN

• Children with oculocutaneous albinism show dermatological and ophthalmological problems. • An early visual impairment may have negative implications on motor, emotional, and cognitive processes that would allow the child to organize his or her experiences.

WHAT IS NEW

• In addition to a variable combination of ocular signs and symptoms, children with oculocutaneous albinism may present an early neurodevelopmental delay and emotional/behavioral difficulties. • An early visual treatment is recommended to improve vision-related performance, neurodevelopment, and any psychological difficulties.

Neurodevelopmental Profile in Children Affected by Ocular Albinism

AIM

The aim of this study was to detail the neurodevelopmental profile of subjects affected by ocular albinism (OA) and to collect data on GPR143 gene analysis.

DESIGN

The design of the study involves a retrospective longitudinal observational case series.

METHODS

We collected data on the neurodevelopmental profile of 13 children affected by OA from clinical annual assessments conducted for a period of 6 years after the first evaluation. We described visual profile, neuromotor development and neurological examination, cognitive profile, communication and language skills and behavioral characteristics. The GPR143 gene analysis was performed as well.

RESULTS

Children presented a variable combination of ocular and oculomotor disorders unchanged during the follow-up, a deficit in visual acuity and in contrast sensitivity that progressively improved. Abnormalities in pattern visual evoked potential were found. No deficits were detected at neurological examination and neuromotor development except for a mild impairment in hand-eye coordination observed in five cases. A language delay was observed in five cases, two of whom had also a developmental quotient delay at 2 years evolving to a borderline/deficit cognitive level at preschool age, difficulties in adaptive behavior and autistic-like features were found. Mutations in the GPR143 gene were identified in the two patients who presented the most severe clinical phenotype.

CONCLUSION

Children with OA may share, in addition to a variable combination of ocular signs and symptoms, a neurodevelopment impairment regarding mostly the cognitive, communicative, and social area, especially those with GPR143 mutation.

ADHD symptoms in neurometabolic diseases: Underlying mechanisms and clinical implications

Neurometabolic diseases (NMDs) are typically caused by genetic abnormalities affecting enzyme functions, which in turn interfere with normal development and activity of the nervous system. Although the individual disorders are rare, NMDs are collectively relatively common and often lead to lifelong difficulties and high societal costs. Neuropsychiatric manifestations, including ADHD symptoms, are prominent in many NMDs, also when the primary biochemical defect originates in cells and tissues outside the nervous system. ADHD symptoms have been described in phenylketonuria, tyrosinemias, alkaptonuria, succinic semialdehyde dehydrogenase deficiency, X-linked ichthyosis, maple syrup urine disease, and several mitochondrial disorders, but are probably present in many other NMDs and may pose diagnostic and therapeutic challenges. Here we review current literature linking NMDs with ADHD symptoms. We cite emerging evidence that many NMDs converge on common neurochemical mechanisms that interfere with monoamine neurotransmitter synthesis, transport, metabolism, or receptor functions, mechanisms that are also considered central in ADHD pathophysiology and treatment. Finally, we discuss the therapeutic implications of these findings and propose a path forward to increase our understanding of these relationships.

Case report: diagnosis and treatment of attention deficit hyperactivity disorder and autism spectrum disorder in patients diagnosed with oculocutaneous albinism

Oculocutaneous albinism (OCA) is a group of autosomal recessive disorders characterized by impairment in the melanin synthesis. We report two siblings with OCA who presented with symptoms of autism spectrum disorder and attention deficit hyperactivity disorder (ADHD). Ocular side effects occured after methylphenidate (MPH) treatment in the patient with ADHD and OCA. The diagnosis of OCA has been associated with difficulties in academic and social fields due to decreased visual activity and differentiation of phenotypic characteristics. Delayed diagnosis of comorbid neuropsychiatric disorders and MPH therapy may increase these difficulties. Patients with OCA require careful evaluation and treatment for neuropsychiatric disorders.

Retinal biomarkers and pharmacological targets for Hermansky-Pudlak syndrome 7

Deletion of dystrobrevin binding protein 1 has been linked to Hermansky-Pudlak syndrome type 7 (HPS-7), a rare disease characterized by oculocutaneous albinism and retinal dysfunction. We studied dysbindin-1 null mutant mice (Dys^−/−) to shed light on retinal neurodevelopment defects in HPS-7. We analyzed the expression of a focused set of miRNAs in retina of wild type (WT), Dys^+/− and Dys^−/− mice. We also investigated the retinal function of these mice through electroretinography (ERG). We found that miR-101-3p, miR-137, miR-186-5p, miR-326, miR-382-5p and miR-876-5p were up-regulated in Dys^−/−mice retina. Dys^−/− mice showed significant increased b-wave in ERG, compared to WT mice. Bioinformatic analysis highlighted that dysregulated miRNAs target synaptic plasticity and dopaminergic signaling pathways, affecting retinal functions of Dys^−/− mice. Overall, the data indicate potential mechanisms in retinal neurodevelopment of Dys^−/− mice, which may have translational significance in HSP-7 patients, both in terms of diagnostic/prognostic biomarkers and novel pharmacological targets.

Increased prevalence of parent ratings of ADHD symptoms among children with bilateral congenital cataracts

AIM

To investigate the behavioral and psychological disorders and the prevalence of parent ratings of attention deficit hyperactivity disorder (ADHD) symptoms among children with bilateral congenital cataracts (CCs).

METHODS

This cross-sectional study investigated children with bilateral CC aged 3-8y (CC group) using Conners' Parent Rating Scale-48 (CPRS-48) from July to December 2016. The abnormal rates of psychological symptoms in CC children and normal vision (NV) children were compared using the Chi-square test. The scores of CC children were compared with those of NV children and the Chinese urban norm using the independent samples t-test and one-sample t-test, respectively.

RESULTS

A total of 262 valid questionnaires were collected. The ratio of CC children to NV children was 119:143. The overall rate of psychological symptoms in CC children was 2.28 times higher than that in NV children (46.22% vs 20.28%, Pearson's χ ²=20.062; P<0.001). CC children showed higher scores for conduct problems, learning problems, impulsiveness/hyperactivity, anxiety, and hyperactivity index than NV children and the Chinese urban norm, particularly between the ages of 3 and 5y. Furthermore, male children aged between 6 and 8y showed a higher impulsive/hyperactive score than females of the same age (t=6.083, P<0.001).

CONCLUSION

Children with bilateral CCs have a higher rate of ADHD symptoms than children with NV. This study provides clinical evidence that screening for psychological symptoms and particularly for ADHD symptoms in children with bilateral CC are recommended for an early diagnosis and timely treatment.

Severe Visual Impairments in Infants and Toddlers in the United States

Introduction

This article describes the most prevalent visual conditions and other demographic characteristics of 5,931 young children with severe visual impairments in 28 states in the United States, the largest sample reported to date. The information presented in this article can assist in planning and implementing programs.

Method

The data were collected at the time of entry into specialized early intervention programs for young children with visual impairments through reviews of records, interviews, and direct observations. They were sent to Babies Count: The National Registry for Children with Visual Impairments, Birth to 3 Years at the American Printing House for the Blind. The data were collected and entered between January 2005 and April 2011.

Results

Cortical visual impairment, retinopathy of prematurity (ROP), and optic nerve hypoplasia were the three most prevalent diagnoses. Approximately 60% were identified as being legally blind, and 65% had disabilities in addition to visual impairments. The mean age of the children at the time of diagnosis was 4.9 (SD = 5.7) months, referral to specialized programs was at 10.5 (SD = 7.8) months, and entry into specialized programs was at 11.6 (SD = 8.0) months. There was an average lag of 5.6 months between the diagnosis and referral.

Discussion

Cortical visual impairment, ROP, and optic nerve hypoplasia continue to be the leading causes of severe, uncorrectable visual impairments in children in the United States. ROP appears to be decreasing in prevalence; however, more children with ROP appear to have additional disabilities. The lag of 5.6 months between diagnosis and referral, a longer lag than was previously reported, is of concern.

Implications for practitioners

Information about the characteristics of children with severe uncorrectable visual conditions is valuable for communicating with families, planning and implementing early intervention and educational programs, and collaborating with medical professionals.

Adult ADHD and Comorbid Somatic Disease: A Systematic Literature Review

OBJECTIVE

To systematically review, synthesize, and appraise available evidence, connecting adult ADHD with somatic disease.

METHOD

Embase, Psychinfo, and Medline databases were searched for studies published from 1994 to 2015 addressing adult ADHD and somatic comorbidity. Somatic conditions were classified according to International Classification of Diseases (ICD-10) codes. Levels of evidence were graded as inconclusive, tentative, or well documented.

RESULTS

Most of the 126 studies included in the qualitative synthesis were small and of modest quality. Obesity, sleep disorders, and asthma were well-documented comorbidities in adult ADHD. Tentative evidence was found for an association between adult ADHD and migraine and celiac disease. In a large health registry study, cardiovascular disease was not associated with adult ADHD.

CONCLUSION

There are few large systematic studies using standardized diagnostic criteria evaluating adult ADHD and somatic comorbidities. Significant associations are found between adult ADHD and several somatic diseases, and these are important to consider when assessing and treating either adult ADHD or the somatic diseases.

ADHD and Vision Problems in the National Survey of Children's Health

PURPOSE

To compare the prevalence of attention deficit/hyperactivity disorder (ADHD) in children with normal vision and with vision problems not correctable with glasses or contact lenses (vision problems) as determined by parent report in a nationwide telephone survey.

METHODS

This cross-sectional study included 75,171 children without intellectual impairment aged 4 to 17 years participating in the 2011 to 2012 National Survey of Children's Health, conducted by the U.S. Centers for Disease Control and Prevention. Demographic information and information regarding vision and ADHD status were obtained by parent interview. Questions asked whether they had ever been told by a doctor or health care provider that the child had a vision problem not correctable with glasses or contact lenses, ADHD, intellectual impairment, or one of 13 other common chronic conditions of childhood. A follow-up question asked about condition severity. The main outcome measure was current ADHD.

RESULTS

The prevalence of current ADHD was greater (p < 0.0001) among children with vision problems (15.6%) compared with those with normal vision (8.3%). The odds of ADHD compared with those of children with normal vision were greatest for those with moderate vision problems (odds ratio [OR], 2.6; 95% confidence interval [95% CI], 1.7 to 4.4) and mild vision problems (OR, 1.8; 95% CI, 1.1 to 2.9). Children with severe vision problems had similar odds of ADHD to those of children with normal vision perhaps because of the small numbers in this group (OR, 1.6; 95% CI, 0.8 to 3.1). In multivariable analysis adjusting for confounding variables, vision problems remained independently associated with current ADHD (OR, 1.8; 95% CI, 1.2 to 2.7).

CONCLUSIONS

In this large nationally representative sample, the prevalence of ADHD was greater among children with vision problems not correctable with glasses or contacts. The association between vision problems and ADHD remains even after adjusting for other factors known to be associated with ADHD.

Prevalence of attention-deficit/hyperactivity disorder among children with vision impairment

PURPOSE

To evaluate the prevalence of parent-reported attention-deficit/hyperactivity disorder (ADHD) in two clinics in Alabama serving children with vision impairment.

METHODS

The medical records of children 4-17 years of age attending the Alabama School for the Blind (ASB) during the 2010-2011 school year or seen at the University of Alabama at Birmingham (UAB) Center for Low Vision Rehabilitation between 2006 and 2010 were retrospectively reviewed. Sociodemographics, ocular characteristics, and parental report of ADHD diagnosis were obtained. The prevalence of ADHD was compared to national and state figures for age-similar children regardless of comorbidities. The prevalence of ADHD, sociodemographic, and ocular characteristics was also compared between clinical sites.

RESULTS

A total of 264 children participated in the study (95 from ASB and 169 from UAB). The prevalence of ADHD among children with visual acuity better than hand motion (n = 245) was 22.9%, which is higher than reported state (14.3%) and national prevalence (9.5%) for children in this age range. The prevalence was similar at ASB (22.4%) and UAB (23.1%). Those with ADHD were similar to those without ADHD with respect to age, sex, and race. Children with ADHD were significantly less likely to have nystagmus and more likely to have better visual acuity (P < 0.05). The prevalence of ADHD among the 19 participants with total or near total vision loss (all from ASB) was 10.5%.

CONCLUSIONS

Our analyses suggest that children with vision impairment may be more likely to be diagnosed with ADHD than children in the general population.

Reading skills in children and adults with albinism: the role of visual impairment

PURPOSE

To evaluate whether visual impairment in albinism contributes significantly to the acquisition of normal reading skills.

METHODS

The authors administered standardized reading tests to 41 children and 18 adults with albinism. The Young Children's Achievement Test was used for children between 4 and 6 years old and the Woodcock-Johnson III was used for children 7 years and older and adults. Parents of children and adult subjects also completed a questionnaire to document developmental, academic, and/or work experiences. The Spearman test was used to evaluate the relationship between binocular best-corrected visual acuity (BCVA) and reading test results.

RESULTS

Standardized reading tests in both children and adults with albinism showed a normal distribution of scores. BCVA did not appear to play a significant role in the development of normal reading ability in these individuals who were visually impaired except for a mild correlation of decreased reading fluency on the Woodcock-Johnson III with decreased BCVA (r = 0.287, P = .046). Many young children with albinism had superior reading skills despite having a BCVA of 20/200 or worse (legal blindness).

CONCLUSION

This study of cognitively normal children and adults with albinism demonstrates that impaired vision during childhood does not by itself significantly impede a child's ability to acquire normal reading skills. However, the lower reading fluency that occurs in the more visually impaired individuals suggests they would benefit, both in the school system and workplace, with an accommodation involving more time to complete reading tasks.

Reading acuity in albinism: evaluation with MNREAD charts

INTRODUCTION

The MNREAD reading acuity (RA) charts use continuous-text reading to measure (1) RA, ie, the smallest size of print that the patient can resolve; (2) maximum reading speed (MRS); and (3) critical print size (CPS), ie, the smallest print that the patient can read with maximum speed. This project used the MNREAD charts to evaluate reading performance in children and adults with albinism to determine the smallest print size recommended to facilitate effortless reading.

METHODS

A total of 63 subjects with albinism were administered the MNREAD test to determine the critical print size for effortless reading. The subjects read continuous, high-contrast text print until they could no longer discern the words. The MRS and CPS were determined with the MNREAD protocol. Presence or absence of nystagmus and strabismus was recorded. Distance visual acuity was measured with ETDRS charts.

RESULTS

The sample included 25 male and 38 female subjects with a median age of 16 years. Median MRS was 150 words per minute. The mean CPS was 0.84 logMAR, notably larger than the mean RA of 0.53 logMAR.

CONCLUSIONS

The MNREAD acuity charts can be used to determine functional reading ability and critical print size for effortless reading in individuals with albinism. The amount of enlargement in print size can be used in educational and vocational recommendations to facilitate reading.