Intellectual functioning in alpha-mannosidosis

Abstract

Alpha-mannosidosis is a rare inherited metabolic disorder (OMIM #248500) caused by mutations in the enzyme α-mannosidase encoded by the gene MAN2B1. Patients have distinct physical and developmental features, but only limited information regarding standardized cognitive functioning of patients has been published. Here we contribute intellectual ability scores (IQ) on 12 patients with alpha-mannosidosis (ages 8-59 years, 10 males, 2 females). In addition, a pooled analysis was performed with data collected from this investigation and 31 cases obtained from the literature, allowing a comprehensive analysis of intellectual functioning in this rare disease. The initial and pooled analyses show that patients with alpha-mannosidosis have variable degrees of intellectual disability but show decline in IQ with age, particularly during the first decade of life. Patients treated with hematopoietic stem cell transplantation tend to show stabilized cognitive abilities.

Keywords: IQ; alpha‐mannosidosis; glycoproteinoses; intellectual disability.

Figure 1

IQ by age for patients with alpha‐mannosidosis. Data points for individuals with multiple evaluations (n = 15) are connected by a line. Patients from the literature (n = 27) are represented with circles and new patients (n = 11) are represented with triangles. See Section 2 for literature citations

Figure 2

IQ by age for pooled patients pre‐ and post‐HCT. Data obtained from the literature (n = 10) and the present study (n = 1). Data points for individuals with multiple evaluations are connected by a line. Six patients had pre‐transplant IQ measures, which are also included in Figure 1