Nonprogressive cerebellar disorder with mental retardation and autosomal recessive inheritance in hutterites

We report a nonprogressive neurological disorder in at least 11 Hutterites with healthy but consanguineous parents. In several of the affected, hypotonia was noted at birth. Retarded motor and mental development became apparent during the first year of life. The age of unsupported walking varied from 5–21 years. Consistent signs were unsteady, broadly based gait and stance, exaggerated deep tendon reflexes mainly in the lower limbs, and mild to moderate mental retardation. Variable signs were extensor plantar reflexes (9/11), short stature (–2SD in 8/11), strabismus (7/11), small muscle mass (6/11), mild intention tremor (3/11), cataracts (1/11), and epilepsy (1/11). CAT scans in two affected sisters showed slight enlargement of the fourth ventricle in one and hypoplasia of the cerebellum in both. The disorder is probably the same as that described earlier under the heading, dysequilibrium syndrome.     

Late infantile autosomal recessive myotonia, mental retardation, and skeletal abnormalities: a new autosomal recessive syndrome.

Four sibs of non-consanguineous parents who had myotonia from late infancy are described. Mild to moderate mental retardation, severe bone abnormalities of the vertebral column (mainly in the thoracolumbar region), and short stature were also observed. Autosomal recessive inheritance is demonstrated. These cases are compared with reported cases of the Schwartz-Jampel syndrome.     

An autosomal recessive mental retardation syndrome with hepatic fibrosis and renal cysts

Two sisters had developmental retardation and congenital hepatic fibrosis. One, 23 years old, had facial anomalies reminiscent of Smith-Lemli-Opitz syndrome, ocular coloboma, and hypoplastic kidneys with a single cyst. The other sister died at 18 months and had an encephalocele and cystically dilated collecting ducts in the renal medulla. Although the manifestations in these two sisters are similar to the Smith-Lemli-Opitz and Meckel syndromes respectively, there are sufficient differences to suggest that they had a separate autosomal recessive MCA-MR syndrome.     

Spondyloepiphyseal dysplasia tarda: a new autosomal recessive variant with mental retardation.

A new variant of spondyloepiphyseal dysplasia tarda with mild to moderate mental retardation is described in three daughters born to healthy, consanguineous parents. The mode of inheritance is compatible with that of an autosomal recessive disorder. The identification of this variant is important, as it enables more precise counselling in families in which sporadic cases with this form of presentation are found.     

Screening for MYO15A gene mutations in autosomal recessive nonsyndromic, GJB2 negative Iranian deaf population

MYO15A is located at the DFNB3 locus on chromosome 17p11.2, and encodes myosin-XV, an unconventional myosin critical for the formation of stereocilia in hair cells of cochlea. Recessive mutations in this gene lead to profound autosomal recessive nonsyndromic hearing loss (ARNSHL) in humans and the shaker2 (sh2) phenotype in mice. Here, we performed a study on 140 Iranian families in order to determine mutations causing ARNSHL. The families, who were negative for mutations in GJB2, were subjected to linkage analysis. Eight of these families showed linkage to the DFNB3 locus, suggesting a MYO15A mutation frequency of 5.71% in our cohort of Iranian population. Subsequent sequencing of the MYO15A gene led to identification of 7 previously unreported mutations, including 4 missense mutations, 1 nonsense mutation, and 2 deletions in different regions of the myosin-XV protein.     

Late-onset localized junctional epidermolysis bullosa and mental retardation: A distinct autosomal recessive syndrome

We present 2 sibs with a local junctional type of epidermolysis bullosa associated with enamel defect of the teeth, dystrophic nails of the feet, and mental retardation. Subluxation of the lenses was evident in 1 of them. This combination found in a brother and a sister seems to represent a distinct autosomal recessive type of epidermolysis bullosa. © 1992 Wiley-Liss, Inc.     

Spastic paresis,glaucoma and mental retardation - a probable autosomal recessive syndrome?

A syndrome of spastic paresis, mental retardation and glaucoma has been described only once previously (Heijbel & Jagell 1981). We describe three brothers, products of a marriage between first cousins once-removed, who appear to have the same syndrome. The brothers are not dysmorphic but they have slowly progressive spastic paresis, moderate mental retardation and glaucoma with secondary cataracts. Documentation of a second consanguineous kindred with this triad of features supports the view that this is a distinct entity with an autosomal recessive mode of inheritance.     

A new locus for autosomal recessive non-syndromic mental retardation maps to 1p21.1-p13.3

Autosomal recessive inheritance of non-syndromic mental retardation (ARNSMR) may account for approximately 25% of all patients with non-specific mental retardation (NSMR). Although many X-linked genes have been identified as a cause of NSMR, only three autosomal genes are known to cause ARNSMR. We present here a large consanguineous Turkish family with four mentally retarded individuals from different branches of the family. Clinical tests showed cognitive impairment but no neurological, skeletal, and biochemical involvements. Genome-wide mapping using Human Mapping 10K Array showed a single positive locus with a parametric LOD score of 4.92 in a region on chromosome 1p21.1-p13.3. Further analyses using polymorphic microsatellite markers defined a 6.6-Mb critical region containing approximately 130 known genes. This locus is the fourth one linked to ARNSMR.     

Genetic heterogeneity in Noonan syndrome: evidence for an autosomal recessive form

Most Noonan syndrome (NS) families are compatible with autosomal dominant inheritance with predominance of maternal transmission. Sporadic patients can be explained by new autosomal dominant mutations. Here we report four Dutch NS patients, two male and two female, each with unaffected consanguineous parents. All four had a typical NS phenotype and presented with hypertrophic obstructive cardiomyopathy (HOCM) at birth. In two cases the HOCM improved, in one case it deteriorated, and in one case it remained constant over 12 years. These patients support the existence of an autosomal recessive form of NS in which HOCM is more frequent than in autosomal dominant NS.     

Involvement of DFNB59 mutations in autosomal recessive nonsyndromic hearing impairment

In a consanguineous Turkish family, a locus for autosomal recessive nonsyndromic hearing impairment (ARNSHI) was mapped to chromosome 2q31.1-2q33.1. Microsatellite marker analysis in the complete family determined the critical linkage interval that overlapped with DFNB27, for which the causative gene has not yet been identified, and DFNB59, a recently described auditory neuropathy caused by missense mutations in the DFNB59 gene. The 352-amino acid (aa) DFNB59 gene product pejvakin is present in hair cells, supporting cells, spiral ganglion cells, and the first three relays of the afferent auditory pathway. A novel homozygous nonsense mutation (c.499C>T; p.R167X) was detected in the DFNB59 gene, segregating with the deafness in the family. The mRNA derived from the mutant allele was found not to be degraded in lymphocytes, indicating that a truncated pejvakin protein of 166 aa may be present in the affected individuals. Screening of 67 index patients from additional consanguineous Turkish families with autosomal recessive hearing impairment revealed a homozygous missense mutation (c.547C>T; p.R183W) that segregates with the hearing impairment in one family. Furthermore, in a panel of 83 Dutch patients, two additional novel mutations (c.509_512delCACT; p.S170CfsX35 and c.731T>G; p.L244R), which were not present in ethnically matched controls, were found heterozygously. Together, our data indicate that also nonsense mutations in DFNB59 cause nonsyndromic hearing loss, but that mutations in DFNB59 are not a major cause of nonsyndromic hearing impairment in the Turkish and Dutch population.     

Late-onset localized junctional epidermolysis bullosa and mental retardation: a distinct autosomal recessive syndrome.

We present 2 sibs with a local junctional type of epidermolysis bullosa associated with enamel defect of the teeth, dystrophic nails of the feet, and mental retardation. Subluxation of the lenses was evident in 1 of them. This combination found in a brother and a sister seems to represent a distinct autosomal recessive type of epidermolysis bullosa.     

New autosomal recessive syndrome of sparse hair,osteopenia, and mental retardation in Mennonite sisters

We report on 2 Mennonite sisters with a syndrome of sparse hair, osteopenia, mental retardation, minor facial abnormalities, joint laxity, and hypotonia. Their asymptomatic consanguineous parents (inbreeding coefficient F = 1/64) have 6 other offspring, 3 of whom died in infancy of type II osteogenesis imperfecta (OI), and 3 of whom are normal. We analyzed collagens synthesized by cultured fibroblasts from these 2 sisters and their parents and detected no major abnormalities. Results of chromosomal and metabolic evaluations including amino acid analysis of plasma, urine, and hair were unremarkable. A literature search and survey of a computerized syndrome identification database did not disclose an identical phenotype. The sisters bear superficial resemblance to several known syndromes which we excluded on clinical and/or biochemical grounds. We conclude that they represent a new autosomal recessive syndrome, distinct from type II OI and perhaps unique to the Mennonite population or to this particular family. © 1992 Wiley-Liss, Inc.     

SCAPER‐associated nonsyndromic autosomal recessive retinitis pigmentosa

Mutations in the gene SCAPER (S ‐phase C yclinA A ssociated P rotein residing in the E ndoplasmic R eticulum) have recently been identified as causing syndromic autosomal recessive retinitis pigmentosa with the extraocular manifestations of intellectual disability and attention‐deficit/hyperactivity disorder. We present the case of an 11‐year‐old boy that presented to our clinic with the complaint of decreased night vision. Clinical presentation, family history, and diagnostic imaging were congruent with the diagnosis of autosomal recessive retinitis pigmentosa. Genetic testing of the patient and both parents via whole‐exome sequencing revealed the homozygous mutation c.2023‐2A>G in SCAPER. Unique to our patient's presentation is the absence of intellectual disability and attention‐deficit/hyperactivity disorder, suggesting that SCAPER‐associated retinitis pigmentosa can also present without systemic manifestations.     

New autosomal recessive syndrome of sparse hair, osteopenia, and mental retardation in Mennonite sisters.

We report on 2 Mennonite sisters with a syndrome of sparse hair, osteopenia, mental retardation, minor facial abnormalities, joint laxity, and hypotonia. Their asymptomatic consanguineous parents (inbreeding coefficient F = 1/64) have 6 other offspring, 3 of whom died in infancy of type II osteogenesis imperfecta (OI), and 3 of whom are normal. We analyzed collagens synthesized by cultured fibroblasts from these 2 sisters and their parents and detected no major abnormalities. Results of chromosomal and metabolic evaluations including amino acid analysis of plasma, urine, and hair were unremarkable. A literature search and survey of a computerized syndrome identification database did not disclose an identical phenotype. The sisters bear superficial resemblance to several known syndromes which we excluded on clinical and/or biochemical grounds. We conclude that they represent a new autosomal recessive syndrome, distinct from type II OI and perhaps unique to the Mennonite population or to this particular family.     

Fallot complex,severe mental,and growth retardation: A new autosomal recessive syndrome?

We report on the syndromic occurrence of the Fallot complex in sibs born to consanguineous Pakistani parents. Additional manifestations included minor facial anomalies, pronounced failure to thrive, and mental retardation. Expression of the syndrome varied. While one of the four patients had cardiac malformations, another sib had only non-cardiac manifestations. The clinical findings suggest a new autosomal recessive syndrome. © 1994 Wiley-Liss, Inc.     

An autosomal recessive form of spastic cerebral palsy (CP) with microcephaly and mental retardation

Cerebral palsy (CP) is defined as any nonprogressive motor deficits resulting from cerebral abnormalities that occur in the prenatal or perinatal period. Symptoms become apparent during the first year of life. Genetic forms of CP account for about 2% in European populations but are thought to cause a substantial proportion in consanguineous families. We have identified a large consanguineous family from Oman with spastic diplegia, microcephaly, and mental retardation. Additional manifestations include hyperreflexia, clumsiness, unstable gait, drooling, and dysarthria. There was phenotypic variability among different individuals, but spastic diplegia, microcephaly, and mental retardation were three constant traits present in all affected individuals.     

New autosomal recessive syndrome of mental retardation,epilepsy, short stature,and skeletal dysplasia

We describe 4 sibs, 2 males and 2 females, affected with a new autosomal recessive MCA/MR syndrome of short stature, cerebral atrophy, epilepsy, skeletal abnormalities, and moderate to severe mental retardation. © Wiley-Liss, Inc.     

A novel nonsense mutation in TUSC3 is responsible for non-syndromic autosomal recessive mental retardation in a consanguineous Iranian family

The genetic basis of autosomal recessive mental retardation (ARMR) is extremely heterogeneous, and there is reason to suspect that the number of underlying gene defects may well go beyond 1,000. To date, however, only less than 10 genes have been implicated in non‐specific/non‐syndromic ARMR (NS‐ARMR). As part of an ongoing systematic study aiming to identify further ARMR genes, we investigated a consanguineous family with three patients with NS‐ARMR. By linkage analysis and subsequent mutation screening we identified a novel nonsense mutation (c.163C > T [p.Q55X]) in the second exon of the TUSC3 gene. This is the third MR causing defect in TUSC3 to be described and the second independent mutation in this gene in a cohort of more than 200 ARMR families from the Iranian population. This argues for a more prominent role of TUSC3 in the etiology of this genetically heterogeneous disorder as compared to most of the other so far identified ARMR genes. © 2011 Wiley‐Liss, Inc.