PMC5121299_01
Patient 1. A and B. Microcephaly, mild hypertelorism, droopy skin on the cheeks of the face and neck, epicanthal folds, small nose with anteverted nares, long philtrum, thin upper lip and retrognathia and blue sclera. C. Loose and wrinkled skin in the abdomen, arms and legs. D. Increased gluteal folds E. Hyperextensible joints. F. and 5th finger clinodactyly G-I. Phenotype at 3 years old.
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Facial manifestations included microcephaly with a wide anterior fontanelle (> 6 cm), droopy skin on the cheeks and prominent nasolabial folds, blue sclerae, mild hypertelorism, epicanthal folds, small nose with anteverted nares, long philtrum, a thin upper lip and retrognathia (Fig. 1A-B). Also observed were markedly loose and wrinkled skin in the abdomen, gluteal zone, arms and legs (Fig. 1C-D) and hyperextensible joints with a single transverse palmar crease and 5th finger clinodactyly (Fig. 1E-F). A follow-up at 3 years revealed an improvement in the skin folds of the neck, abdomen and gluteal area (Fig. 1G-I).
IEF of serum transferrin showing an abnormal type II profile for both patients. C, control sample; P1, Patient 1; P2, Patient 2. Numbers in the edge correspond to the number of sialic acids in the transferrin isoforms.
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Serum transferrin IEF revealed an abnormal type II profile (Fig. 2).
Mass spectrometry of serum transferrin and ApoCIII. A. Transferrin profiles of Patients 1 and 2 showing an increase of trisialylated transferrin compared to a normal control. B. ApoCIII profile of Patient 1 showing a normal glycosylation profile and Patient 2 showing an abnormal profile compared to a normal control. C. Transferrin and ApoCIII glycoform ratios of profiles shown in A and B with the reference range values obtained from a series of independent controls.
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Transferrin and Apolipoprotein CIII were profiled by mass spectrometry and confirmed a combined hypoglycosylation defect (Fig. 3).
Sanger sequencing chromatograms showing mutations. A. Patient 1 showing the homozygous mutation in genomic DNA (c.187C>T) and his parents showing it in a heterozygous fashion. B. Patient 2 showing exon 18 skipping in cDNA. C. Patient 2 showing a homozygous mutation in genomic DNA (c.2293C>T) and his parents showing it in a heterozygous fashion. The control sequence is from a healthy individual.
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PCR amplification and sequencing of ATP6V0A2 using cDNA revealed the presence of two transcripts, a full length transcript with a previously reported nonsense mutation in exon 18 that causes a premature stop codon (c.2293C>T; p.Q765X) and a transcript lacking exon 18 (r.2176_2293del) (see Fig. 4B). Analysis of genomic DNA revealed no intronic mutations in the 5' or 3' boundary of exon 18 nor its deletion but did show that the patient was homozygous for the c.2293C>T mutation (see Fig. 4C).
PMC5121299_02
IEF of serum transferrin showing an abnormal type II profile for both patients. C, control sample; P1, Patient 1; P2, Patient 2. Numbers in the edge correspond to the number of sialic acids in the transferrin isoforms.
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PMC5121299_02_gr2.jpg
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Serum transferrin IEF revealed an abnormal type II profile (Fig. 2).
Mass spectrometry of serum transferrin and ApoCIII. A. Transferrin profiles of Patients 1 and 2 showing an increase of trisialylated transferrin compared to a normal control. B. ApoCIII profile of Patient 1 showing a normal glycosylation profile and Patient 2 showing an abnormal profile compared to a normal control. C. Transferrin and ApoCIII glycoform ratios of profiles shown in A and B with the reference range values obtained from a series of independent controls.
gr3.jpg
PMC5121299_02_gr3.jpg
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Transferrin and Apolipoprotein CIII were profiled by mass spectrometry and confirmed a combined hypoglycosylation defect (Fig. 3).
Sanger sequencing chromatograms showing mutations. A. Patient 1 showing the homozygous mutation in genomic DNA (c.187C>T) and his parents showing it in a heterozygous fashion. B. Patient 2 showing exon 18 skipping in cDNA. C. Patient 2 showing a homozygous mutation in genomic DNA (c.2293C>T) and his parents showing it in a heterozygous fashion. The control sequence is from a healthy individual.
gr4.jpg
PMC5121299_02_gr4.jpg
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PCR amplification and sequencing of ATP6V0A2 using cDNA revealed the presence of two transcripts, a full length transcript with a previously reported nonsense mutation in exon 18 that causes a premature stop codon (c.2293C>T; p.Q765X) and a transcript lacking exon 18 (r.2176_2293del) (see Fig. 4B). Analysis of genomic DNA revealed no intronic mutations in the 5' or 3' boundary of exon 18 nor its deletion but did show that the patient was homozygous for the c.2293C>T mutation (see Fig. 4C).
Patient 2. A. Facial features are droopy skin on the cheeks, small nose with anteverted nares, long philtrum and marked nasolabial folds. B and C. Loose and wrinkled skin in the abdomen. D. Axial brain MRI showing widened Virchow-Robin spaces in the white matter.
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Physical exploration revealed a persistently low weight, height and cephalic circumference (< 5th percentile), a wide anterior fontanelle (> 6 cm), droopy skin on the cheeks of the face, small nose with anteverted nares, long philtrum, marked nasolabial folds and large everted ears with helix hypoplasia (Fig. 5A). Also observed were markedly loose and wrinkled skin in the neck, abdomen, gluteal zone, arms and legs (Fig. 5B-C) and hyperextensible joints with a single transverse palmar crease. A brain MRI showed widened Virchow-Robin spaces in the white matter with no other apparent malformations (Fig. 5D).