ABSTRACT
Kinesin proteins are critical for various cellular functions such as intracellular transport and cell division, and many members of the family have been linked to monogenic disorders and cancer. We report eight individuals with intellectual disability and microcephaly from four unrelated families with parental consanguinity. In the affected individuals of each family, homozygosity for likely pathogenic variants in KIF14 were detected; two loss-of-function (p.Asn83Ilefs*3 and p.Ser1478fs), and two missense substitutions (p.Ser841Phe and p.Gly459Arg). KIF14 is a mitotic motor protein that is required for spindle localization of the mitotic citron rho-interacting kinase, CIT, also mutated in microcephaly. Our results demonstrate the involvement of KIF14 in development and reveal a wide phenotypic variability ranging from fetal lethality to moderate developmental delay and microcephaly.
Subject(s)
Intellectual Disability/genetics , Kinesins/genetics , Microcephaly/genetics , Oncogene Proteins/genetics , Child , Child, Preschool , Female , Humans , Intellectual Disability/pathology , Kinesins/chemistry , Kinesins/metabolism , Loss of Function Mutation , Microcephaly/pathology , Mutation, Missense , Oncogene Proteins/chemistry , Oncogene Proteins/metabolism , Pedigree , Phenotype , Protein Domains , SyndromeABSTRACT
INTRODUCTION: The Mucopolysaccharidoses (MPS) are rare inherited metabolic disorders. They are characterized by the progressive systemic deposition of Glycosaminoglycans (GAGs). GAGs accumulate in the myocardium and the cardiac valves. Enzyme Replacement Therapy (ERT) is available for MPS I, II, and VI. However, ERT does not appear to improve cardiac valve disease in patients with valve disease present at the start of ERT. AIM: To evaluate the cardiac involvement in Egyptian children with MPS. MATERIALS AND METHODS: Echocardiograms (ECG) were done for 34 patients. Both quantitative and qualitative Glycosaminoglycans (GAGs) in urine and enzyme assay confirmed the diagnosis. Mitral, tricuspid and aortic valves were evaluated for increased thickness, regurgitation and/or stenosis, left ventricular chamber dimensions, septal and posterior wall thicknesses. RESULTS: The patients' age ranged from 0.9-16 years (median age 4 years). They included 19 cases of MPS I (55.9%), 3 cases of MPS II (8.8%), 2 cases of MPS III (5.9%), 6 cases of MPS IV (17.6%) and 4 cases of MPS VI (11.8%). Heart murmur was heard in 9 of the participants (9/34) (26%). However, 15 patients (15/34) (44%) revealed cardiac lesions on ECG examinations. Mitral regurge (47%), followed by pulmonary hypertension (40%), were the most frequent findings. CONCLUSION: The absence of Cardiac murmurs does not exclude the heart involvement. Cardiac valve dysfunction may not be reversible. Regular ECG should be routinely warranted in children with MPS and early ERT are recommended.